home Auditorium 7 Intraatrial block. Heart block: complete and partial, various localizations - causes, signs, treatment Causal factors of pathology

Intraatrial block. Heart block: complete and partial, various localizations - causes, signs, treatment Causal factors of pathology

Heart block is a disturbance in the conduction of electrical impulses in one of its parts. The disease can be either independent or act as a complication in other pathologies of the cardiovascular system. For heart block disease, the symptoms, as well as treatment and diagnostic methods for each individual type or stage will be individual. To understand in detail the principle of the existence of pathology, you need to have an idea of how electrical impulses move through the parts of the heart.

How electrical impulses are conducted

Electrical impulses appear in the upper part of the right atrium - the place of their origin is called the sinus node. Through it, each newly appeared electrical impulse is transmitted to the remaining parts of the atrium. Then, through the atrioventricular node connecting the atria and ventricles (in the medical literature it can be referred to as AV), the impulse spreads to the ventricular section, once there it branches into all its sections. Heart block is a disruption of the described process at one of its stages.

Classification of the disease

Depending on the area in which the conduction of the electrical impulse was disrupted, heart block can be divided into the following types:

atrial;
intraatrial;
atrioventricular;
ventricular

For these pathologies, experts consider 3 degrees of their manifestation.

I degree of the disease is characterized by slow conduction of electrical impulses. It is easily diagnosed using an ECG and does not always require special treatment, but is dangerous due to the risk of the disease progressing to a deeper stage.
At the next stage, some impulses fall out in some area of conduction. Patients suffering from second degree heart block periodically feel dizziness, pain in the chest, and fatigue, but sometimes this may not manifest itself symptomatically. The nature of treatment for stage II heart disease varies depending on the location of its occurrence. Usually an electrocardiogram is not enough to detect and confirm it; if this diagnosis is suspected, the cardiologist may refer the patient for laboratory tests.
If the electrical impulse in one or another part does not pass at all, doctors diagnose a third degree heart block. To detect it, in addition to ECG and laboratory tests, instrumental tests will also be required. Patients diagnosed with it usually become completely incapacitated, constantly feel weak and drowsy, often experience chest pain, and have a noticeable decrease in pulse rate. In some cases, the disease in this form is fraught with sudden death.

Treatment for heart block will vary depending on its severity and type.

Atrial block

Atrial block is caused by a disturbance in the conduction of electrical impulses in the atrium. The permanent form of the disease is often confused with bradycardia - a decrease in heart rate, since the clinical picture of both pathologies is similar.

The cause of atrial block may be the incorrect use of certain antiarrhythmic drugs, as well as drugs used to lower blood pressure and treat heart failure (in this case, a mandatory consultation with a cardiologist is required to discontinue/replace drugs or adequately select their dosage).

In addition, it is often observed in patients with diabetes mellitus with hyperglycemia - increased levels of glucose in the blood. In some cases, this disease is caused by a brain tumor or inflammatory processes occurring in it. Even less commonly, atrial block occurs due to congenital cardiomegaly - an enlargement of the heart to a size significantly larger than normal, defects of the mitral and aortic valves, and thyroid disease. It itself can also be congenital or genetic.

The initial stage of atrial block is not considered a serious pathology - people who develop it are usually recommended to limit themselves to general methods of maintaining health. For grades II and III of the disease, the cardiologist may prescribe the drugs bellataminal, belloid, ephedrine or atropine. When the heart rate decreases to 40 beats/min and frequent loss of consciousness occurs, the patient is “implanted” with an implant responsible for generating impulses that determine the heart rate.

Intraatrial block

Intraatrial block consists of a slow or complete absence of electrical impulse transmission from the right atrium to the left. Caused by coronary heart disease and other pathologies of the cardiovascular system. It is rare, and it mainly affects patients over 80 years of age, but there are cases of intra-atrial blockade in middle-aged patients.

It cannot be treated, but with proper treatment of the diseases that caused it, it can be completely eradicated from the body or the most favorable course of the disease can be achieved. The exception is complete intraatrial block - it usually occurs several hours before death in patients with serious cardiac disorders, but in medical practice one can also find cases of complete cure of the pathology in the patient.

Atrioventricular block

Atrioventricular (AV) or atrioventricular block is a slow or complete cessation of the conduction of an electrical impulse in the same section of its passage. Patients who have suffered a myocardial infarction often have this disease on their medical records. The causes of atrioventricular block can also be weakening of the cardiac muscle, heart, coronary artery disease and rheumatoid heart disease, previous diphtheria or other infections. Atrioventricular block sometimes occurs in newborns and in some cases is inherited.

First degree atrioventricular block can occur as a normal physiological phenomenon in people who are actively involved in sports (especially athletes), as well as in young people and teenagers. Potassium salts, cardiac glycosides, cordarone and other drugs may have side effects associated with this disorder.

Patients with I degree AV block due to myocardial infarction, and at the same time needing to take drugs that impair cardiac conduction, require the introduction of an endocardial electrode into the ventricle. To prevent the disease from progressing to a deeper stage, persons with a history of myocarditis may be prescribed prednisolone or another glucocorticoid drug. All other carriers of this pathology do not require special treatment.

With II degree atrioventricular block, patients may feel a slow contraction of the pulse. A short-term cardiac arrest is possible, during which the patient will complain of dizziness and darkening of the eyes. The doctor may recommend installing a pacemaker (or an endocardial electrode in the ventricle) to prevent the disease from progressing to stage III, but this is not always necessary.

Symptoms of third degree atrioventricular heart block: weakness and fatigue, dizziness, short loss of consciousness, in which the patient sometimes experiences involuntary urination or defecation. Blood pressure in this condition exceeds normal levels.

If the full form of the disease appears as a result of atrial fibrillation, the patient will experience only rare heart failure and elevated blood pressure without other symptoms. III degree of atrioventricular block is the basis for installing a pacemaker, with the exception of the congenital nature of the disease and during pregnancy. In some situations, a pacemaker can also be installed in pregnant women (for example, in case of hemodynamic impairment).

Ventricular block

A disturbance in the conduction of electrical impulses in the ventricular region indicates that the patient has a corresponding type of heart block. The reason for its occurrence may be:

congenital;
high blood pressure;
pathological lesions of the heart muscle;
cardiac ischemia;
overdose of cardiac glycosides.

Ventricular blockade, regardless of its stage, does not require special therapy. To prevent the development of ventricular block and its elimination, maximum efforts must be made to treat the disease that caused its occurrence.

This form of pathology, depending on the exact location, can be supplemented by atrioventricular, including its full stage. This process usually takes about 10 years.

Under no circumstances should you self-medicate for cardiovascular diseases.
When playing sports, it is absolutely not advisable to immediately take on an increased amount of load. The opposite rule is also true - for athletes who have already accustomed the heart muscle to heavy loads, it is very dangerous to abruptly stop training.
Regardless of your health status, you should adhere to the principles of proper nutrition; it is advisable to reduce the consumption of excessively salty, spicy and fatty foods to a minimum, especially for people over 40 years of age.
Patients who already have heart block should promptly report to their cardiologist any changes in their health and adverse events when taking prescribed medications.
Blood pressure should be checked regularly, and if its values deviate from normal values for a long time, you should consult a doctor to prescribe therapy that can maintain it. The concept of “working pressure” is a myth. The absence of poor health with high blood pressure does not mean that this or that number on the tonometer is in fact the “individual norm” for this or that person.
Complete cessation of alcohol and smoking is an excellent preventive measure. If you can’t quit bad habits on your own, don’t be afraid to seek help from a doctor.

Strict prevention can be a full-fledged treatment of the first stages of the disease - it is better to limit yourself to dubious pleasures than to observe unnecessary complications.

It occurs against the background of already existing destructive processes in the organ. Often this pathology begins its development in the uterine period, and then the heart block will be congenital. But it can also be acquired and transient. The danger of this disease is that symptoms may not show themselves for a long time, and a person will think that he is healthy, but in fact pathological processes will occur in his organ.

Heart block can be:

complete when the impulses stop coming;
incomplete when the rhythms begin to slow down.

In the first case, there is a lack of asystole, which causes the heart rate to slow down, which in some situations can cause heart failure.

Causes of the disease

The main element that is involved in the transmission of all impulses is the sinus node, located in the right atrium above. P-cells and T-cells are responsible for the impulse. The former are intended to create an impulse, and the latter - to carry it out. If the heart is healthy, then its indicator will be equal to beats per minute.

The cardiac muscle has a rather complex structure with many pathways: Bachmann's tract, Wenckebach's tract, Thorel's tract. Normally, the impulse always passes along the first two paths, since they are the shortest. There is such an important element in the organ as the bundle of His. It has two main parts: the initial section, which is separated from the contractile myocardium, and the branching section, which is directly involved in the process of conducting impulses to the ventricles of the heart.

The purpose of the right and left bundle branches is that they provide direction to other parts of the organ. There are two branches on the left process. This area has nerve fibers that provide contractions at a frequency of beats per minute.

Heart block occurs due to obstruction of impulses along at least one of these paths or sections. Depending on which pathway is affected, this disease can take the following forms:

Heart blocks occur due to functional or organic damage to the organ. As for the latter, the following points may be the cause of this problem:

myocardial infarction, when focal or diffuse cardiosclerosis develops;
cardiomyopathy;
myocarditis;
with systemic lesions, when the process involves the conduction system of the organ;
amyloidosis;
sarcoidosis;
various benign and malignant neoplasms;
diseases of the neuromuscular system;
thyrotoxicosis;
diabetes;
some infections also cause heart block;
in case of intoxication of the body;
taking medications containing glycosides, novocainamide and quinidine can provoke such an illness.

As mentioned above, such a pathology can be congenital, but it is quite rare in this form.

Blockades of the right and left leg of His

Depending on which part of the His bundle is affected, certain prognosis and consequences may occur.

If the problem lies in the right leg, then inhibition or absence of conductive impulses will be noted throughout the entire area. People who have a history of some kind of defect, myocardial infarction, cardiosclerosis, or hypertension are more prone to this pathology. This form may result in paroxysmal supraventricular tachycardia. To determine the blockade of the right leg, electrocardiography is used. If there are no total processes, then pronounced symptoms will not be observed in this case.
As for the left leg, the blockade can be either partial or complete. There are often cases when the blockade process affects both legs, that is, both the right and the left at the same time.

If there is a lesion on the left side, then in parallel with this the patient may have a myocardial infarction, and this, in turn, complicates the whole picture. Symptoms will be observed depending on what the underlying disease is. A person may feel a constant pressing pain in the heart area, and even after taking medications, the discomfort does not go away. Such sensations cause fear of imminent death, decreased body tone, and increased sweating.

In such a situation, the main thing is to hospitalize the patient on time.

Treatment of blockade: nuances

Like any other heart disease, blockade has varying degrees of severity. Therefore, it is very important to undergo an examination in time so that it is possible to determine what exactly the problem is.

The cardiologist, based on the results obtained, can calculate the course of treatment.

Heart block is treated mainly with antiarrhythmic drugs. But they also have their own classification:

Class I - drugs that are aimed at blocking sodium channels. There is also a division here:
- IA - “Quinidine”, “Novocainamide”, “Rytmilen”;
- IV - “Lidocaine”, “Difenin”, which have a lidocaine-like effect;
- ІС - “Enkainid”, “Gilurythmal”, “Ritmonorm”, intended for sharp blockade of sodium channels.
Class II - drugs with beta blockers. These include drugs such as Atenol, Propranolol, Esmolol, Nadolol and Bisoprolol.
Class III is intended for blocking potassium channels. This group of medications: Sotalol, Amiodarone and Nibentan.
Class IV includes drugs that have a blocking effect on the conduction system. This category includes Diltiazem and Verapamil.

But if the drugs are taken independently, without the supervision of a cardiologist, then instead of helping, they can only provoke an attack.

Category 1-2 blockade has symptoms in the form of interruptions in the functioning of the heart muscle, tinnitus and headaches. Category 3 entails a violation of the blood supply, and this already requires emergency care. For a “mild” form of the disease, Atropine (0.1%) is prescribed, which is administered intravenously into the body. To treat “severe” forms, aggressive therapy using Dopamine is prescribed. But here it is immediately worth noting that this drug is administered only under ECG control. The fact is that such a medication tends to cause tachycardia, which, if uncontrolled, will lead to ventricular fibrillation. As an alternative, adrenaline can be used.

If such treatment does not produce the desired effect, the patient is sent for cardiac pacing. But in the future, an operation is performed so that it is possible to install an artificial pacemaker.

If the blockade is a consequence of a heart attack, then this can lead to an increase in adenosine in the tissues. In such cases, monitoring the patient is simply necessary in order to detect complications in time and initiate treatment.

Some features

If the patient is diagnosed with complete blockade, he may be prescribed cardiac pacing. But it is carried out only in the following cases:

if the patient has an acute form of heart failure, which causes pulmonary edema, arterial hypotension and arrhythmogenic collapse;
when a person developed and developed cardiac ischemia;
in cases where the patient began to complain of constant fainting, and they occur even without active activity on the part of the patient;
during the period of resuscitation, a block of the heart muscle developed;
if such a process occurred as a result of another acute disease.

All these points necessitate the use of cardiac stimulation. All other options allow the use of pharmaceutical drugs, some of which will be aimed at inhibiting the blockade, while others will increase cardiac output. In any case, the doctor, when prescribing this or that medicine, focuses on the existing problem in order to help the patient maintain the heart in stable hemodynamics.

In conclusion, I would like to note that if there is a heart block or other heart disease, in no case should you joke about it. Self-medication can also cause irreparable harm to health. Therefore, consultation and a full examination by a cardiologist are simply necessary.

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I take Cardioactive to maintain my heart muscle. Doctor reko.

Thanks for the interesting article. My mom also started testing.

My child has congenital portal hypertension (at one year old).

Thank you for the detailed information.

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Heart block and its consequences

The heart will work like a MOTOR!

You will forget about tachycardia if you do it before bed.

In order for the human heart to supply blood to all tissues and organs, it must beat continuously and at a certain frequency - beats per minute. In addition, the health of the entire body largely depends on the correctness of the heart rhythm, that is, on whether the intervals between contractions of the organ are equal. Even the slightest delay in the operation of the “main pump” entails tissue hypoxia, which will ultimately result in a number of very serious problems. Oxygen starvation of the brain and other organs most often develops due to a disease such as heart block. There are different types of blockades - less dangerous and severe, which can only be corrected surgically.

What is heart block

The electrical impulse originates in the sinus node - the pacemaker. Next, the excitation wave travels through the atria, which, after contraction, transmit the impulse through the Torel, Bachmann and Wenkenbach bundles to the AV node and further to the His bundle. Then, along the branches of the His bundle, the impulse is distributed into the smallest branches of the conduction system - Purkinje fibers. With a decrease in automaticity, it is possible to lengthen the time of passage of the excitation wave in any area, which in cardiology is considered as a number of separate diseases.

Heart blocks are a group of pathologies related to heart rhythm disturbances, that is, arrhythmias in which there is a slowdown in cardiac conduction with the development of bradycardia. During blockade, the conduction system of the heart does not work correctly, causing heart contractions with a frequency of less than 50 beats per minute, which is caused by congenital dysfunction or acquired replacement of myocardial muscle tissue with connective (scar) tissue. Heart block can be an isolated conduction disorder in the heart, or it can be combined with atrial fibrillation, other types of arrhythmias, or combined with other types of blockades. In young people, the disease is observed, on average, in 1% of cases; in older people, this figure rises to 2.5%. Some types of blockades are considered normal and develop in 5% of the population.

The main danger from heart blocks for humans is that a pathological change in the excitation of the ventricles causes a delay in contractions lasting from a fraction of a second to a minute or more, which can lead to oxygen starvation of the brain and fainting, as well as clinical death. The consequences of the pathology will largely depend on its cause and location, that is, on the location of the lesion in the conduction system of the heart. Where altered muscle cells appear, along which an excitation wave should normally pass, a block appears in the path of the electrical impulse. This can occur in both the atria and ventricles.

Classification of blockades

According to the location of the pathological process, heart block can be as follows:

Sinotrial, or sinoauricular, blockade with damage to the sinus node in the area of the right atrium.
Atrial (intraatrial) block - the impulse disrupts its path along the anterior wall of the atrium.
Interatrial, or Bachmann's block - the impulse slows down in the area from the sinoatrial node to the left atrium.
Atrioventricular (transverse) block - the transition of excitation from the atria to the ventricles is disrupted.
Intraventricular block (bundle branch block) - blocking of the impulse occurs at the level of the lower element of the conduction system in the part of the left or right bundle branch.

Intraventricular block can exist in the following forms:

interventricular block (damage to the conduction pathways of the interventricular septum);
block of the right ventricle of the heart (blocking the impulse in the anterior or posterior part of the left bundle branch);
blockade of the left ventricle of the heart (blocking the excitation wave in any part of the left bundle branch).

Classification of the disease according to the time of its onset includes the following types:

Transient blockade.
Persistent (permanent blockade).
Progressive blockade.
Intermittent blockade.

A very important sign of pathology is the severity of impulse conduction disorders in the heart. According to this criterion, the disease is classified as follows:

Complete heart block - impulses in the heart are not carried out to the lower portion of the myocardium at all.
Incomplete (partial) blockade - there is a slowdown in the conduction of impulses or their partial conduction to the myocardial zone located below the pathological area.

Atrioventricular block is divided into three degrees of severity:

First degree AV block - the impulse is delayed in the area of the AV node from normal 0.18 seconds to 0.3 seconds or more. The disease is detected only by the results of a cardiogram.
Second degree AV block - there is a more serious slowing of conduction through the atrioventricular node.
Third degree AV block is a complete block in which no impulses enter the ventricles at all. This pathology is very dangerous and can lead to death.

Causes of the disease

An incomplete type of blockade often occurs in healthy people, does not harm them and does not require treatment. For example, with minor anomalies in the structure of the heart (false chord, mitral valve prolapse and others), partial blockade of the right leg of His may appear, which does not progress in the future and does not change hemodynamics. Vegetative-vascular dystonia can have the same consequences. At a young age, partial forms of pathology can occur due to overexcitation of the vagus nerve due to intense sports or heavy physical work.

Sometimes cases of congenital heart block are recorded, which appears against the background of intrauterine development disorders. This disease most often accompanies heart valve disease and other congenital heart defects, which are noted in a newborn immediately after birth. Acquired causes of the development of pathology are:

autoimmune diseases, especially systemic lupus erythematosus;
thyrotoxicosis;
diphtheria;
myocarditis;
connective tissue damage (vasculitis);
acquired heart defects;
tumors and metastases of the heart;
myxedema;
sarcoidosis;
amyloidosis;
rheumatism;
syphilis of the heart muscle;
myocardial infarction;
cardiosclerosis;
fibrosis, myocardial hemochromatosis;
cardiomyopathy;
Severe ischemic heart disease;
advanced arterial hypertension;
diabetes mellitus and other metabolic disorders;
electrolyte imbalance;
atherosclerosis of the coronary arteries.

Blockade is also possible after an overdose of cardiac glycosides, antiarrhythmic drugs, beta blockers. Preparations based on the foxglove plant are dangerous in relation to the development of pathology. Also, heart blocks can become a complication of a number of surgical operations, for example, for the treatment of heart defects, valve replacement and treatment of arrhythmias. Conduction disturbances in the heart are possible due to an overdose of alcohol and drugs.

Symptoms of manifestation

As a rule, with mild degrees of the disease, the patient does not experience any unpleasant symptoms at all. Partial blockades can only be detected by a cardiac cardiogram during routine diagnostics or medical examination. With sinoauricular block, when the impulse slows down or does not arrive at all from the sinus node to the atria, the patient often experiences unpleasant sensations in the retrosternal area, shortness of breath, weakness, impaired performance, and sometimes dizziness. If the loss of impulses occurs frequently, and also with a complete blockade, a person regularly has a feeling of a sinking heart, there is dizziness, which is accompanied by tinnitus and often turns into fainting.

Particularly striking symptoms are caused by complete AV blockades. They always manifest themselves as arrhythmias of the bradycardia type, and are also combined with signs of underlying cardiac pathology. So, against the background of normal health, the patient may suddenly develop an attack of arrhythmia, but there is another variant of the clinical course of the disease, when deterioration lasts for a long time, so the body adapts to it, the patient feels satisfactory.

Symptoms of serious conduction disorders in the heart are:

increased fatigue;
decreased tolerance to physical activity;
discomfort in the chest;
chest pain when playing sports;
later - pain at rest;
short-term cardiac arrest;
“flies” before the eyes;
dizziness, sudden general weakness;
nausea, lightheadedness;
noise, hum, ringing in both ears;
headaches, mainly of the occipital localization;
vomit;
low-grade fever.

The most unpleasant are Morgagni-Adams-Stokes attacks, which are accompanied by rare pallor and blue lips, the appearance of cold sticky sweat, convulsions, decreased pulse, fainting for a few seconds or even prolonged loss of consciousness (up to 3 minutes). With a complete block of the bundle branch, which is combined with organic damage to the heart, the first symptom may be acute heart failure with shortness of breath and severe cough, foamy sputum, cyanosis of the lips, skin, and the development of a state of shock.

In newborn children, the pulse is much higher than in adults, therefore, if a child’s pulse is detected to be less than 80 beats per minute, he is always given a cardiogram to confirm or refute the diagnosis of “complete atrioventricular block”. This disease can be congenital and is sometimes diagnosed even in utero. Symptoms of congenital AV block are pallor of children, retardation in growth and development in comparison with peers, breast refusal, slow heartbeat, lethargy, cyanosis of the lips and fingers. Due to weakness and circulatory failure, such babies are prone to fainting, they often experience convulsions and Morgagni-Adams-Stokes attacks. If the attack is prolonged, then respiratory arrest and asystole may occur - cessation of heartbeat. Congenital blockages can cause the death of a child in the first year of life.

Complications and their prevention

The prognosis is favorable only for partial (incomplete) heart blocks, when this condition can be treated with medications, or therapy is not required at all. Complete blockades have an unfavorable prognosis; they quickly lead to disability with complete incapacity for work. Complications of such conditions often include myocardial infarction, acute heart failure, ventricular fibrillation, cardiogenic shock, and with such consequences the mortality rate is very high.

Complete blockades require early diagnosis and treatment for a number of other reasons. They tend to progress, and therefore provoke a number of chronic diseases, which sooner or later end in death. Thus, chronic heart failure in combination with complete AV block can lead to fainting and collapse, and also inevitably causes the development of cardiac ischemia and kidney disease. Various ectopic arrhythmias, for example, ventricular tachycardia, bradycardia, are also often combined with conduction disorders and can lead to ischemic stroke, dementia, and a number of other consequences. The only way to improve the prognosis is surgical treatment, during which a pacemaker is implanted to ensure a normal heart rhythm.

Diagnostic methods

If the symptoms described above develop, the doctor may assume the presence of conduction disturbances already during the collection of anamnesis and examination of the patient. Listening to heart sounds gives an idea of a slower rhythm (bradycardia) and cardiac arrest characteristic of a particular blockade. However, there is a basic and more informative diagnostic method - an ECG, which allows you to clarify the type of disease according to its main characteristics:

Sinoatrial block is a periodic loss of ventricular P-QRS complexes due to the fact that not all impulses reach the atria and ventricles. Also, the RR interval can be increased by 2 times or more.
Intraatrial block - splitting of the P wave or the presence of a widened P wave. Complete Bachmann block on the ECG is expressed by the presence of a negative additional P wave.
1st degree AV block - an increase in the PQ interval, 2nd degree - a gradual increase in the duration of the PQ interval, loss of the QRST complex with preservation of the P wave. With complete 3rd degree AV block, the RR and PP intervals are constant, while the PP interval is greater than the RR interval. The QRS complex is widened and deformed.
Bundle branch block - with a complete block of the right bundle branch, there is a widening of the QRS complex above 0.12 seconds in all leads, the formation of notches in the complex, an increase in the time of internal deviation in the right chest lead. Complete blockade of the left leg according to the ECG is manifested by the widening of deformed R-waves, which have a wide or split apex; in leads V1, V2, III, aVF there are widened deformed S waves, as well as a QS complex with a wide or split apex.

It is not always possible to detect heart block using a single ECG, so Holter monitoring is often recommended to clarify the diagnosis. The procedure is performed during the day and is very informative for transient blockades, as it can reflect heart rhythm problems that occur at night, during exercise, stress, etc. The patient may also be prescribed a stress ECG, which will reveal the degree of tolerance to physical activity and establish the class of coronary artery disease and heart failure. To find the cause of heart block, which lies in its organic lesions, an ECG, MRI of the heart, chest X-ray, coronary angiography, EPI, a number of laboratory tests and other necessary studies are done.

First aid for heart block

Since with complete heart blocks the development of Morgagni-Adams-Stokes attacks is possible, the patient’s relatives should know how to provide first aid and what to do in the future. The person should be laid on a flat surface, with a small pillow placed under the head. As first aid, you need to give an Izadrina tablet under the tongue, and in case of loss of consciousness, take measures to bring the person to his senses. If there is no cardiac activity and breathing, indirect cardiac massage and artificial respiration are performed until the ambulance arrives.

Emergency doctors use the following actions for emergency treatment of complete blockade:

intravenous administration of Adrenaline, Norepinephrine;
subcutaneous administration of Atropine;
novocaine blockade of the cardio-aortic plexus;
cardioversion using a defibrillator;
urgent hospitalization in intensive care.

Treatment methods

Drug therapy

In general, treatment involves taking measures to restore rhythm and influence the underlying disease. Usually, with partial blockades, only monitoring the patient and his healthy lifestyle is required. When the disease is caused by an overdose or long-term use of medications, they are immediately discontinued. To eliminate the etiological factor for the development of conduction disorders, antibiotics (for autoimmune myocarditis), NSAIDs and glucocorticosteroids (for autoimmune pathologies), statins (to normalize cholesterol levels), etc. may be required.

The disease can be treated with medication by taking the following medications:

Beta blockers (Betaloc).
Beta-adrenergic stimulants (Isoprenaline, Orciprenaline).
Diuretics (Furosemide).
Vasodilators (Amlodipine).
Antiarrhythmic drugs (Quinidine).
Calcium channel blockers (Corinfar, Nifedipine).
Antihypertensive drugs (Perindopril, Enalapril).

Surgical methods

Unfortunately, complete blockades rarely respond to medication therapy, and the only method of treating them with a positive effect is surgery. If a patient experiences Morgagni-Adams-Stokes attacks, then in the vast majority of cases a pacemaker must be implanted. Indications for permanent pacemaker are:

severe drop in heart rate;
complete AV block in combination with ectopic arrhythmias, heart failure, coronary artery disease and other heart diseases;
hemodynamic disturbances due to conduction disturbances;
asystole according to the results of Holter monitoring lasting up to 2-3 seconds or more.

If complete blockades occur during myocardial infarction or other acute heart pathologies, surgery to temporarily install a pacemaker may be required.

Folk remedies

Usually, traditional medicine advises taking herbs and other products during blockades that improve the conductivity and functioning of the heart as a whole, and eliminate the symptoms of ischemia and heart failure. The recipes are as follows:

Pour 400 ml of boiling water over a tablespoon of valerian root and leave in a thermos for 10 hours. Strain, drink 3 times a day in an amount of 30 ml.
Pour 2 teaspoons of cornflower flowers with a glass of boiling water, leave for an hour, strain. Drink half a glass three times a day half an hour before meals.
Take calendula tincture twice a day, 20 drops, diluted with a small volume of water.
Pour a tablespoon of horsetail herb into 350 ml of boiling water and let it brew for 2 hours. Drink a tablespoon 6 times a day.

Dietary nutrition is of great importance for all types of pathologies affecting the conductivity of the heart. The foods that the patient eats must include a lot of potassium, as well as other minerals that nourish the heart muscle. Baked potatoes, seeds, honey and bananas, dried apricots, dried fruits, and black currants are especially useful. Calcium and magnesium are also needed by a patient with heart blockade, and therefore bran, spinach, legumes, cucumbers, avocados, as well as dairy foods, seafood, and pumpkin seeds should be consumed.

The patient needs to include more plant foods in their diet, which contain a lot of vitamins and fiber. It is better to give up large amounts of salt, fats, and sweets. If you have high cholesterol and obesity, you should take all measures to lose weight, because the load on the heart is much lower with normal weight. A person under any kind of blockade is prohibited from smoking or abusing alcohol. A healthy lifestyle should be supplemented with properly selected physical activity, which helps develop and strengthen the myocardium.

A child with congenital or acquired complete blockade cannot lead the lifestyle that his peers have. He is not fit for military service; heavy physical activity, regular school physical education, and attending sports clubs and clubs are contraindicated for him. Whether pregnancy is possible during the blockade is decided by a council of doctors in each individual case individually.

Preventive measures

Since heart blocks in most cases complicate the course of the underlying cardiac or non-cardiac pathology (usually ischemic heart disease), prevention comes down to timely and adequate treatment of these diseases. You should also carefully monitor the doses of medications taken to avoid overdose, give up bad habits, and lead a healthy lifestyle.

Are you one of the millions who have heart disease?

Have all your attempts to cure hypertension been unsuccessful?

Have you already thought about radical measures? This is understandable, because a strong heart is an indicator of health and a reason for pride. In addition, this is at least human longevity. And the fact that a person protected from cardiovascular diseases looks younger is an axiom that does not require proof.

The materials presented are general information and cannot replace medical advice.

Heart block: complete and partial, various localizations - causes, signs, treatment

Disturbances in the passage of the impulse between the sinoatrial node and the beginning of the branching of the His bundle, which is called heart block, cause disruption of the heart rhythm and decreased blood supply to the brain.

Heart block, in which the passage of the excitation impulse slows down, is considered partial. If the impulse ceases to be transmitted completely, then complete heart block is formed.

When a partial blockade occurs, most patients feel quite healthy, attributing a slight malaise to fatigue after a hard day at work, stress, etc., since they do not feel significant disturbances in cardiac activity. In many cases, it is detected on an ECG during the next preventive examination or when seeking medical help. At the same time, the word “blockade” causes panic among many. So what kind of disease is this, and what danger does it pose to humans? Let's try to explain.

What is heart block?

work of the conduction system of the heart

Let's start with the fact that the normal functioning of the heart is facilitated by electrical impulses generated in the sinoatrial node. From it they are distributed throughout the atria, the contractions of which contribute to the transmission of the impulse further, through the atrioventricular node to the atrioventricular His bundle. From there it is distributed into areas through smaller branches. With a decrease in the automaticity of the sinus node, the passage of the impulse slows down, and the interval between atrioventricular contractions increases (lengthens).

Sometimes the impulse does not travel through the conduction system at all. In this case, there is no contraction of the atria or ventricles. A long pause occurs (atrial asystole), which is called the Wenckebach period. When it occurs, conductivity is restored again, thanks to the ectopic rhythm, which is called the “rescuing” rhythm. And the next atrioventricular interval is already of normal length. Symptoms with incomplete (partial) heart block are almost completely absent, since it does not disrupt the blood supply to the brain. Most often, partial heart block is accompanied by slight dizziness and slight malaise.

Complete heart block is characterized by the occurrence of bradysystole - a sharp decrease in the number of ventricular contractions (up to 30-40), when the number of atrial contractions remains normal. This almost always causes significant circulatory problems. Patients complain of shortness of breath, dizziness, and their vision suddenly becomes dark.

Sometimes a drop in cardiac activity (a sharp decrease in ventricular contractions to 15 per minute) causes cerebral ischemia. In this case, a Morgagni-Adams-Stokes (MAS) attack occurs: epileptiform convulsions develop, and the person loses consciousness for several minutes. Before it occurs, he begins to feel weak, a feeling of intense heat arises in his head, then he suddenly turns pale and loses consciousness. This condition is called instantaneous blockade. It develops when a violation of sinus rhythm turns into ventricular automaticity. Repeated attacks of MAS often cause death.

Video: heart block on ECG

The video shows an intermittent (alternating) blockade of either the right or left bundle branch

Heart blockades - briefly about the types

The following types of blockade are distinguished depending on where the obstacles that arise that cause disruption of the impulse patency are localized.

Sinoatrial blockade

Sinoatrial (SA) block is usually caused by excessive stimulation of the vagus nerve or organic damage to the sinus node. It is characterized by conduction disturbances in the area between the atria and the sinoatrial node, accompanied by loss of complete cardiac contraction, which is detected by auscultation (listening). The nature of the loss is irregular.

Sinoatrial blockades also develop under the influence of glycosides prescribed for the treatment of heart disease, potassium supplements and quinidine. It also occurs in people in excellent health who engage in various sports when their physical activity increases.

Partial (incomplete) blockade, associated with a decrease in the activity of the sinoatrial node, is asymptomatic. No treatment is required for this type of blockage. If there is a significant decrease in the activity of the sinus node caused by increased excitability of the vagus nerve, a course of therapy with atropine administered subcutaneously is carried out, and sympathomimetics can be used.

Intraatrial block

When it occurs, the patency of the excitation is disrupted inside the atria.

Atrioventricular block

The cause of atrioventicular (AV) blockade is the pathology of the passage of the impulse that excites the ventricles simultaneously through all three branches of the His bundle. They are divided according to degrees, which determine the severity of the disease.

1st degree

First degree heart block occurs when there is a delay in the passage of the electrical impulse through the atrioventricular region. It is detected only through an ECG. If cardiac activity is normal, the duration of the interval of impulse passage from the atria to the ventricles (P - Q) is 0.18 s. When a 1st degree blockade develops, the impulse conduction interval (P – Q) increases to 0.3 s and higher.

2nd degree

A 2nd degree block is characterized by a further increase in conduction disturbances in the atrioventricular node. This disorder has three types (Mobitz).

An ECG with Mobitz I (type 1) shows a gradual increase in the P – Q interval, with the occurrence of Wenckebach periods (ventricular complexes periodically fall out).
For Mobitz II (second type), the P–Q interval remains unchanged, but a loss of ventricular contractions is noted.
Type three (Mobitz III) 2nd degree AV heart block is accompanied by an increase in the pathology of electrical impulse patency with loss of contractions. The electrocardiogram shows that the ventricular QRS complex contracts more often.

3rd degree

With the 3rd degree of blockade, the transmission of impulses in the atrioventricular node stops completely. And they begin to contract spontaneously, regardless of each other. Myocardial pathologies, drug intoxication and other factors lead to the development of complete blockade.

Intraventricular block

Intraventricular blockades (ventricular) are associated with the formation of pathology of the pathways located below the atrioventricular node: in the His bundle or one or more of its legs. With this type of blockade, the exciting impulse directed to the ventricles is delayed or not transmitted at all.

types of intraventricular blocks

Video: Lesson on Heart Blocks

Etiology

Basically, the causes of heart block lie in the progression of diseases, such as:
1. myocarditis of thyrotoxic, diphtheria or autoimmune type;
2. diffuse connective tissue diseases;
3. heart defects and tumors;
4. sarcodia and amyloidosis;
5. myxedema;
6. syphilis affecting the heart and myocardial defects caused by rheumatism;
7. myocardial infarction or cardiosclerosis.
No less common causes are drug poisoning caused by exceeding the dosage of certain drugs: quinidine (against arrhythmia), Corinfar, verapamil, digitalis and a number of others. Digitalis preparations are especially dangerous for heart blockades of any kind.
Incomplete blockade often occurs in completely healthy people. Most often it is caused by overexcitation of the vagus nerve, which is caused by increased stress during training or physical work.
There have been cases of congenital blockade that occurs as a result of pathology of intrauterine development. In this case, newborns are diagnosed with heart defects, etc.
Blockade can also be caused by certain types of surgical interventions used to eliminate various heart defects and other anomalies.

Blockades of intraventricular localization

The most common is intraventricular heart block. It has several varieties, which are classified based on which branch of the His bundle the pathology arose. The mechanism by which the excitatory impulse is transmitted to the ventricles from the atria includes three branching segments. They are called the legs of His. First there is a branch to the RV (right ventricle). It is called the bundle branch (right). Next comes the left segment (leg), which is directed downward. Being a continuation of the main trunk, it is thicker than the others. Just below the segment branching to the pancreas, the left segment divides into posterior and anterior branches. Along the posterior branch, excitation is transmitted to the septum, and along the anterior branch - directly to the ventricle, located on the left side.

Damage to any branch of the His bundle contributes to the formation of a single-bundle block. If conduction is impaired in two branches, then we are talking about a two-bundle blockade. If the pathology develops in all three legs (complete bundle lesion), this means the occurrence of a complete three-bundle transverse block of the atrioventricular (distal) type.

Based on the location of the conduction pathology, there is a division into right ventricular and left ventricular blockades. If conduction pathology occurs along the anterior or posterior part of the left segment of the His bundle, a blockade of the left ventricle of the heart is formed.

Pathology of the conduction of the anterosuperior left leg mainly progresses with the development of diseases leading to thickening of the wall of the left ventricle (its hypertrophy). This may be myocarditis, anomalies of the interventricular septum, aortic heart disease, heart attack, etc. There is a violation of the patency of the excitation along the anterior section of its side wall. It is distributed abnormally, starting from the lower areas and gradually rising upward. That is, the septum between the ventricles is first excited, then the impulse is transmitted to the lower portion of the posterior wall. At the end of the period, along the anastomoses, the excitation reaches the anterior section of the lateral wall. The cardiogram shows that the QRS interval is wider than during the normal passage of the impulse by 0.02 s. The R wave is of greater height, and the S wave is of greater depth. At the same time, abnormal Q waves are formed.
When excitation completely ceases to be transmitted through the His bundle (along its left leg), a complete left ventricular block occurs. But along the segment on the right side the impulse passes in a normal rhythm. And only after excitation occurs in the right part of the septum and RV, the impulse is sent to the left ventricle. Conduction disorders of this type are caused by severe heart diseases, which give complications in the form of various defects of the myocardium and impulse-conducting system.
When the left ventricular block is incomplete, the passage of the electrical impulse to the branching slows down. It is brought to the LV transseptally, in a retrograde direction (from left to right) along the right branch of the His bundle, starting from the RV.

The development of blockade of the right ventricle in most cases is caused by diseases leading to its overstrain and the formation of wall thickening. Anomalies of this type are often caused by intoxication of the body with medications prescribed to eliminate disturbances in the functioning of the heart (beta blockers, quinidine, etc.). RV block very often develops in people whose hearts are completely healthy. The anomaly in the patency of the impulse in this case lies in the fact that the septum and LV are first excited, and only then the impulse is transmitted to the RV.

From the above, the conclusion follows: the pathology of the passage of the excitation impulse in any of the branches of the His bundle is a partial blockade of one of the ventricles, on the side of which a pathological interruption of the branch occurred. Excitation to the blocked ventricle is transmitted in an abnormal “bypass” way: through the septum and the ventricle corresponding to the normally functioning branch.

Intraventricular blockades can be identified mainly by electrocardiographic examination. The cardiogram shows a deviation of the electrical axis to the left by an angle of up to 90° with a negative value in case of left ventricular block caused by conduction disturbances in the anterior segment. Deviation of the electrical axis to the right by an angle of up to 90° with a positive value indicates a blockade of the left posterior area. The QRS complex remains unchanged. To clarify the diagnosis, Holter monitoring is performed (taking readings for 24 hours or more).

Video: lesson on bundle branch blocks

Why is heart block dangerous?

Complete atrioventricular block is considered the most dangerous, as it has serious consequences, manifested in the following:

The occurrence of chronic heart failure, accompanied by fainting and collapse. Over time, it will progress, causing exacerbations of cardiovascular diseases (in particular coronary artery disease), chronic kidney diseases, etc.
Against the background of a slow rhythm, ectopic arrhythmias develop, including ventricular tachycardia.
A common complication is bradycardia, leading to hypoxia (oxygen starvation) of the brain and attacks of MAS, the frequent occurrence of which in older people is the cause of dementia.
Sometimes an attack of MAS causes ventricular fibrillation, leading to sudden death. Therefore, it is important to provide emergency assistance in a timely manner: if necessary, perform a cardiac massage (indirect) or perform forced ventilation.
During heart attacks or post-infarction conditions, complete heart block can cause cardiogenic shock.

Diagnosis

When some of the ventricular contractions are lost, their number decreases. This happens both with complete and partial blockade, including functional blockade. To identify the nature of its occurrence, a so-called atropine test is used. The patient is given atropine. An incomplete blockade, the occurrence of which is not associated with pathological changes, then disappears literally after half an hour.

On the electrocardiogram, only the waves are modified, showing that the impulse exciting the contraction passes from the atrium to the ventricle very slowly. With partial second-degree heart block, the cardiogram shows that the impulse passes with a slowdown. The wave of atrial contraction is recorded, but there is no wave indicating ventricular contraction. Partial blockade of the right leg is recorded on the cardiogram by slight changes in the thoracic leads on the right side and the appearance of small notches on the S wave.

Pathology treatment method

Treatment for heart block (antrioventricular) is prescribed depending on the type and cause of its occurrence. For first-degree atrioventricular block, constant clinical monitoring of the patient is sufficient. Drug therapy is carried out if his condition worsens. If the blockade develops against the background of a heart disease (myocarditis or acute myocardial infarction), then the underlying disease is first eliminated. The treatment method for 2nd and 3rd degree blockade is selected taking into account the location of the conduction disorder.

If the blockade is of the paroxysmal type, then treatment is carried out with sympathomimetic agents (isadrin) or subcutaneous administration of atropine.
With a distal blockade, drug therapy does not give the desired effect. The only treatment is electrical stimulation of the heart. If the blockade is acute and occurs as a result of myocardial infarction, then temporary electrical stimulation is performed. In case of persistent blockade, electrical stimulation should be carried out continuously.
In case of sudden complete blockade, if it is not possible to perform electrical stimulation, an Isuprel or Euspiran tablet (or half a tablet) is placed under the patient’s tongue. For intravenous administration, these drugs are diluted in glucose solution (5%).
Complete heart block that develops against the background of digitalis intoxication is eliminated by withdrawing glycosides. If the blockade, the rhythm of which does not exceed 40 beats per minute, persists even after discontinuation of glycosides, Atropine is administered intravenously. In addition, Unitol injections are given intramuscularly (up to four times a day). If necessary (for medical reasons), temporary electrical stimulation is performed.

Under the influence of drugs on the vagus nerve, there are often cases when complete heart block turns into partial.

help yourself

In case of incomplete blockade, specific drug treatment is not required. But care must be taken to reduce the likelihood of its transition to more severe forms. And the symptoms that arise, such as dizziness and heaviness in the chest, also cannot be ignored. Therefore, it is recommended to reconsider your lifestyle and diet, and give up bad habits. If you experience discomfort caused by the blockade, do the following:

If you feel dizzy and weak, you need to lie down (or sit down). Stop while walking.
Do a simple breathing exercise:
- take a deep breath;
- While inhaling, hold your breath for a few seconds (the longer the better);
- Exhale all the air completely.
- Repeat the exercise until the condition improves.

Complete heart blocks

Let's look at what a complete intraventricular block caused by pathological changes looks like on an ECG. The amount of damage to each branch of the left leg of His is indicated by the deviation of the isoline towards negative or positive values. It is located neutrally (zero position), when excitation is transmitted to the ventricles in a normal rhythm. If the passage of the impulse is disrupted, a widening of the QRS complex is recorded, which in some cases reaches more than 0.18 s.

With a significant increase in depolarization caused by conduction disturbances in the His bundle, early repolarization occurs. On the electrocardiogram this process is recorded as follows:

The ST segment in the left chest is shifted below the isoline; the T wave takes the shape of a negative equilateral triangle.
The ST segment in the right parts of the chest is above the isoline, the T wave has a positive value.

When the right ventricular block occurs, the following occurs:

A low S wave of greater width is formed;
The R wave, on the contrary, is narrow but high;
The QRS complex is shaped like the letter M.
Secondary repolarization (early) is reflected in the chest leads on the right by an upwardly convex ST segment, which has a slight downward shift. In this case, the T wave is inverted (upside down).

Complete atrioventricular block, which occurs as a result of pathological changes in the myocardium or against the background of an overdose of certain types of drugs, can develop in a distal or proximal type.

The proximal type of block occurs when the ventricular pacemaker is located in the atrioventricular node. On the ECG, this type of blockade is indicated by a normal (not widened) QRS complex, the frequency of ventricular contractions is quite high (up to 50 per minute).
In the distal type, the ventricular pacemaker has a lower idioventricular location. It is the bundle of His with all its branches. It is called a third-order automatic center. The electrocardiogram shows that the number of ventricular contractions is reduced, it does not exceed 30 per minute. This is indicated by a widening of the QRS complex of more than 0.12 s and the layering of the P wave on the ventricular QRS complex. It may have a changed shape (if the automatic impulse occurs below the point at which the His bundle begins to branch). The ventricular complex retains an unchanged shape if the initial point of localization of the automatic impulse is located in the bundle itself.

With atrioventricular block, simultaneous contraction of the ventricles and atria occurs. This gives an increased sound of the first tone, which is called “cannon”. It is clearly audible when listening. The symptoms of this type of blockade depend on the degree of circulatory disturbance and the causes that cause it. If the frequency of ventricular contractions is high enough (at least 36 per minute), and there are no concomitant diseases, then patients do not experience discomfort or unpleasant sensations. In some cases, when cerebral blood flow decreases, dizziness occurs, and consciousness begins to periodically become confused.

With an increase in the duration of the interval between ventricular contractions, partial AV block can become complete, causing acute circulatory disorders in the brain. It is often accompanied by a slight eclipse of consciousness and heart pain. In more severe cases, MAS attacks occur, accompanied by convulsions, and the person loses consciousness for a short time. Prolonged ventricular arrest can cause instant death due to ventricular fibrillation.

Drug therapy for complete blockade

Therapy for complete blockade of any type is carried out based on etiology and pathogenesis.

If the reason lies in the excessive use of medications, their dosage is adjusted, up to complete withdrawal.
To eliminate the blockade caused by cardiac genesis, it is necessary to use beta-agonists (orciprenaline, isoprenaline).
Relief of MAS attacks is carried out with an isadrin tablet under the tongue, as well as the administration of atropine subcutaneously or intravenously. If stable heart failure occurs, vasodilators and diuretics are prescribed. The use of cardiac glycosides is possible in small dosages with constant monitoring of the patient's condition.
The resulting arrhythmia is eliminated by quinidine.
To treat blockade that occurs in a chronic form, symptomatic drugs are used: Corinfar, Belloid, Teopec.

Radical methods include implantation of a pacemaker. Indications for its use are:

low ventricular rate;
increased period of asystole (more than 3 s);
occurrence of MAS attacks;
complete blockade, complicated by persistent heart failure, angina pectoris and other diseases of the cardiovascular system.

Forecast

A favorable prognosis is given only with partial blockades. The development of a complete third-degree block leads to complete disability, especially if it is complicated by heart failure or occurs against the background of myocardial infarction. The implantation of a pacemaker will make it possible to make more favorable prognoses. When used, some patients may experience partial restoration of their ability to work.

Features of heart block localizations

His bundle and its blockade

His bundle block has distinctive features. It may be constant or appear periodically. Sometimes its occurrence is associated with a certain heart rate. But the most important thing is that this type of heart block is not aggravated by severe disease. And although this blockade in itself does not pose a threat to human health, it can serve as a harbinger of more serious heart disease (in particular myocardial infarction). Therefore, it is necessary to periodically undergo a heart examination using an ECG.

A pathological conduction disorder, the location of which becomes the bundle branch, can pose a threat to life. This is explained by the fact that she is a fourth-order pacemaker. It regenerates low-frequency pulses (no more than 30 per minute). It should be noted that the highest frequency impulse (up to 80 per minute) is formed in the sinoatrial node. The second-order atrioventricular node that follows it produces impulses with a decrease in frequency to 50 per minute. The His bundle (third-order pacemaker) generates impulses at a frequency of 40 per minute. Therefore, in the event of obstruction of the excitatory impulse along the pacemakers of all levels, they are automatically formed in the Purkinje fibers. But their frequency decreases to 20 per minute. And this leads to a significant decrease in the blood supply to the brain, causes its hypoxia and leads to pathological irreversible disorders in its work.

Sinoatrial heart block

violation of the generation or conduction of impulses at the level of the sinus node

A distinctive feature of sinoatrial block (SB) is that it can occur simultaneously with other types of heart rhythm disturbances and conduction pathologies. Sinoatrial block is sometimes caused by a weak sinus node. It can be permanent, transient or have a latent form.

In this case, three stages of its manifestation are distinguished.

At the first stage, the passage of the impulse through the sinoatrial region is delayed. It can only be detected by electrophysiological studies.
At the second stage, two types of SB should be considered. With the development of the first type, a periodic blocking of one impulse occurs at the exit from the atria. Sometimes several impulses in a row are blocked at once, with Weckenbach periodicity. The R-R interval corresponding to the pause is extended. But its value is less than twice the R-R interval that precedes the pause. Gradually, the intervals that follow a long pause become shorter. It is detected during a standard ECG, on which the pulse frequency is displayed without change.
The second type is characterized by a sudden disruption of impulse conduction, in which there are no Weckenbach periods. On the cardiogram, the pause is recorded as doubling, tripling, etc. pauses R-R.
The third stage is a complete disruption of impulse conduction in the atria.

Interatrial block

One of the small rare heart rhythm disorders is interatrial block. Like all other types, it has three stages.

The impulse of excitation is delayed.
Periodic blocking of the excitatory impulse entering the left atrium.
Dissociation of atrial activity or complete conduction disturbance.

The third stage is characterized by the automaticity of the formation of impulses from two sources at once: the sinoatrial and gastroatrial node. This is due to the fact that due to the emerging pathology of the sinus node, the number of impulses formed in it sharply decreases. At the same time, an accelerated formation of the number of impulses in the AV node occurs. This leads to simultaneous contraction of the ventricles and atria, regardless of each other. This type of blockade has another name - “Pre-ventricular dissociation” or dissociation with interference. On the electrocardiogram it is recorded together with normal contractions. When listening, a more sonorous “gun” tone is heard from time to time.

Heart block in childhood

In childhood and adolescence, the same types of blockade are formed as in adults, differing only in the cause of occurrence: acquired (due to a disease) or congenital etiology. Acquired forms in children and adolescents are secondary, and develop as a complication after surgery to eliminate various cardiac pathologies, or against the background of diseases with an inflammatory or infectious etiology.

Congenital blockade can be caused by the following reasons:

Diffuse damage to the mother's connective tissue.
The presence of type II diabetes mellitus (insulin-dependent) in the mother. This syndrome is called Legerne disease.
Not fully formed right leg of the His bundle.
Anomaly in the development of the interatrial and interventricular septa.
M.Lev disease

The most dangerous is the third degree of atrioventricular or complete transverse block caused by damage to all three legs of the His bundle. When they occur, the conduction of impulses to the ventricles from the atria is completely absent. It does not always have pronounced symptoms. Its only manifestation is bradycardia.

But as it progresses, there is a gradual stretching of the heart chambers, hemodynamic disturbances with a slowdown in overall blood flow. This leads to a deterioration in the supply of oxygen to the brain and myocardium. As a result of hypoxia, children experience neuropsychic disorders. They remember and assimilate educational material poorly, and lag behind their peers in physical development. The child often experiences dizziness, weakness, and slight fainting. Any stressful situation and increased physical activity can lead to fainting.

In the treatment of complete blockade in children, anti-inflammatory and hormonal drugs, antioxidants, nootropics and vitamin complexes are used. Severe forms, in which drug therapy is ineffective, are recommended to be eliminated by cardiac pacing. Pacemakers are also used in the treatment of congenital forms of heart block accompanied by bradycardia. Emergency assistance for loss of consciousness (attack of MAS) consists of closed (indirect) cardiac massage, administration of atropine or adrenaline. Continuous monitoring of conductivity through an ECG is recommended.

Congenital heart blocks often cause the death of a child in the first year of life. In a newborn they are manifested by the following symptoms:

Blueness or cyanosis of the skin, lips;
Increased anxiety or, conversely, excessive lethargy;
The baby refuses to take the breast;
He experiences increased sweating and increased heart rate.

For mild forms, drug treatment is not required. But the child needs constant monitoring by a cardiologist. In some cases, surgical intervention is recommended, which can save the baby’s life.

Hello! I had surgery for tetralogy of Fallot in childhood, and now they have diagnosed 2nd degree AV block, Mobitz 1. Can I play sports? What to do with stabbing pain in the heart area?

Hello! You did not specify what exactly you have now besides the blockade, what sports you want to do, what worries you besides the pain in your heart, but in any case, you need to contact a cardiologist for pain; you cannot self-medicate. You need to be very careful with sports, especially if you have a serious arrhythmia. Contact a cardiologist who will explain what you can do and what you should avoid.

Yes, this is possible, but the anesthesiologist must know about all your problems.

Are operations during anesthesia contraindicated if there is a partial block of the His bundle? Will they lead to deterioration?

Hello! If there is incomplete blockade of the bundle branches, then anesthesia is possible, but the anesthesiologist should be aware of all these changes.

Disturbances in the passage of the impulse between the sinoatrial node and the beginning of the branching of the His bundle, which is called heart block, cause disruption of the heart rhythm and decreased blood supply to the brain.

Heart block, in which the passage of the excitation impulse slows down, is considered partial. If the impulse ceases to be transmitted completely, then complete heart block is formed.

When a partial blockade occurs, most patients feel quite healthy, attributing a slight malaise to fatigue after a hard day at work, stress, etc., since they do not feel significant disturbances in cardiac activity. In many cases, it is not detected during the next preventive examination or when seeking medical help. At the same time, the word “blockade” causes panic among many. So what kind of disease is this, and what danger does it pose to humans? Let's try to explain.

What is heart block?

Let's start with the fact that the normal functioning of the heart is facilitated by electrical impulses generated in the sinoatrial node. From it they are distributed throughout the atria, the contractions of which contribute to the transmission of the impulse further, through the atrioventricular node to the atrioventricular His bundle. From there it is distributed into areas through smaller branches. With a decrease in the automaticity of the sinus node the passage of the impulse slows down, the interval increases (lengthens) between atrioventricular contractions.

Sometimes the impulse does not travel through the conduction system at all. In this case, there is no contraction of the atria or ventricles. A long pause occurs (atrial), which is called the Wenckebach period. When it occurs, conductivity is restored again, thanks to the ectopic rhythm, which is called the “rescuing” rhythm. And the next atrioventricular interval is already of normal length. Symptoms with incomplete (partial) heart block are almost completely absent, since it does not disrupt the blood supply to the brain. More often partial heart block is accompanied by slight dizziness and slight malaise.

Sometimes a drop in cardiac activity (a sharp decrease in ventricular contractions to 15 per minute) causes. In this case, epileptiform convulsions develop, and the person loses consciousness for several minutes. Before it occurs, he begins to feel weak, a feeling of intense heat arises in his head, then he suddenly turns pale and loses consciousness. This condition is called instantaneous blockade. It develops when a violation of sinus rhythm turns into ventricular automaticity. Repeated attacks of MAS often cause death.

Video: heart block on ECG

The video shows an intermittent (alternating) blockade of either the right or left bundle branch

Heart blockades - briefly about the types

The following types of blockade are distinguished depending on where the obstacles that arise that cause disruption of the impulse patency are localized.

Sinoatrial blockade

Usually calls excessive stimulation of the vagus nerve, or organic damage to the sinus node. It is characteristic of the area between the atria and the sinoatrial node, accompanied by loss of complete heartbeat, which is detected by auscultation (listening). The nature of the loss is irregular.

Sinoatrial blockades also develop under the influence of potassium and quinidine drugs prescribed for the treatment of heart disease. It also occurs in people in excellent health who engage in various sports when their physical activity increases.
Partial (incomplete) blockade, associated with a decrease in the activity of the sinoatrial node, is asymptomatic. No treatment is required for this type of blockage. In cases of significant pain caused by increased excitability of the vagus nerve, a course of therapy with atropine administered subcutaneously is carried out; sympathomimetics can be used.

Intraatrial block

When it occurs the patency of excitation is disrupted inside the atria.

Atrioventricular block

The cause is pathology of the passage of the impulse that excites the ventricles simultaneously through all three branches of the His bundle. They are divided according to degrees, which determine the severity of the disease.

1st degree

2nd degree

A 2nd degree block is characterized by a further increase in conduction disturbances in the atrioventricular node. This disorder has three types (Mobitz).

3rd degree

Intraventricular block

Associated with the formation of pathology of the pathways located below the atrioventricular node: in one or more of its legs. With this type of blockade, the exciting impulse directed to the ventricles is delayed or not transmitted at all.

types of intraventricular blocks

Video: Lesson on Heart Blocks

Etiology

Basically, the causes of heart block lie in the progression of diseases, such as:
1. myocarditis of thyrotoxic, diphtheria or autoimmune type;
2. diffuse connective tissue diseases;
3. and heart tumors;
4. sarcodia and amyloidosis;
5. myxedema;
6. syphilis affecting the heart and myocardial defects caused by;
7. myocardial infarction or.
No less common causes are drug poisoning caused by exceeding the dosage of certain drugs: quinidine (against arrhythmia), Corinfar, verapamil, digitalis and a number of others. Digitalis preparations are especially dangerous for heart blockades of any kind.
Incomplete blockade often occurs in completely healthy people. Most often it is caused by overexcitation of the vagus nerve, which is caused by increased stress during training or physical work.
There have been cases of congenital blockade that occurs as a result of pathology of intrauterine development. In this case, newborns are diagnosed with heart defects, etc.
Blockade can also be caused by certain types of surgical interventions used to eliminate various heart defects and other anomalies.

Blockades of intraventricular localization

Pathology of the conduction of the anterosuperior left leg mainly progresses with the development of diseases leading to. This may be myocarditis, anomalies of the interventricular septum, aortic heart disease, heart attack, etc. There is a violation of the patency of the excitation along the anterior section of its side wall. It is distributed abnormally, starting from the lower areas and gradually rising upward. That is, the septum between the ventricles is first excited, then the impulse is transmitted to the lower portion of the posterior wall. At the end of the period, along the anastomoses, the excitation reaches the anterior section of the lateral wall. The cardiogram shows that the QRS interval is wider than during the normal passage of the impulse by 0.02 s. The R wave is of greater height, and the S wave is of greater depth. At the same time, abnormal Q waves are formed.
When excitation completely ceases to be transmitted through the His bundle (along its left leg), a complete left ventricular block occurs. But along the segment on the right side the impulse passes in a normal rhythm. And only after excitation occurs in the right part of the septum and RV, the impulse is sent to the left ventricle. Conduction disorders of this type are caused by severe heart diseases, which give complications in the form of various defects of the myocardium and impulse-conducting system.
When the left ventricular block is incomplete, the passage of the electrical impulse to the branching slows down. It is brought to the LV transseptally, in a retrograde direction (from left to right) along the right branch of the His bundle, starting from the RV.

From the above the following conclusion follows: The pathology of the passage of the excitation impulse at any of the branches of the His bundle is a partial blockade of one of the ventricles, on the side of which a pathological interruption of the branch occurred. Excitation to the blocked ventricle is transmitted in an abnormal “bypass” way: through the septum and the ventricle corresponding to the normally functioning branch.

Intraventricular blockades can be identified mainly by electrocardiographic examination. The cardiogram shows a deviation of the electrical axis to the left by an angle of up to 90° with a negative value in case of left ventricular block caused by conduction disturbances in the anterior segment. Deviation of the electrical axis to the right by an angle of up to 90° with a positive value indicates a blockade of the left posterior area. The QRS complex remains unchanged. To clarify the diagnosis, readings are taken over a period of 24 hours or more.

Video: lesson on bundle branch blocks

Why is heart block dangerous?

The most dangerous is considered complete atrioventricular block., since it has serious consequences, manifested in the following:

The occurrence of chronic heart failure, accompanied by fainting and collapse. Over time, it will progress, causing exacerbations of cardiovascular diseases (in particular), chronic kidney diseases, etc.
Against the background of a slow rhythm, they develop, including ventricular tachycardia.
A frequent complication is that leads to hypoxia (oxygen starvation) of the brain and attacks of MAS, the frequent occurrence of which in older people is the cause.
Sometimes an attack of MAS causes sudden death. Therefore, it is important to provide emergency assistance in a timely manner: perform, if necessary, or perform forced ventilation.
During heart attacks or post-infarction conditions, complete heart block can cause.

Diagnosis

Pathology treatment method

Treatment for heart block (antrioventricular) is prescribed depending on the type and cause of its occurrence. For first-degree atrioventricular block, constant clinical monitoring of the patient is sufficient. Drug therapy is carried out if his condition worsens. If the blockade develops against the background of a heart disease (or acute), then the underlying disease is eliminated first. The treatment method for 2nd and 3rd degree blockade is selected taking into account the location of the conduction disorder.

If the blockade is of the paroxysmal type, then treatment is carried out with sympathomimetic agents (isadrin) or subcutaneous administration of atropine.
With a distal blockade, drug therapy does not give the desired effect. The only treatment is electrical stimulation of the heart. If the blockade is acute and occurs as a result of myocardial infarction, then temporary electrical stimulation is performed. In case of persistent blockade, electrical stimulation should be carried out continuously.
In case of sudden complete blockade, if it is not possible to perform electrical stimulation, a tablet is placed under the patient’s tongue Isuprel or Euspirana(or half a tablet). For intravenous administration, these drugs are diluted in glucose solution (5%).
Complete heart block that develops against the background of digitalis intoxication is eliminated by withdrawing glycosides. If the blockade, the rhythm of which does not exceed 40 beats per minute, persists even after discontinuation of glycosides, intravenous Atropine. In addition, intramuscular injections are given Unitola(up to four times a day). If necessary (for medical reasons), temporary electrical stimulation is performed.

Under the influence of drugs on the vagus nerve, there are often cases when complete heart block turns into partial.

help yourself

In case of incomplete blockade, specific drug treatment is not required. But care must be taken to reduce the likelihood of its progression to more severe forms. And the symptoms that arise, such as dizziness and heaviness in the chest, also cannot be ignored. Therefore, it is recommended to reconsider your lifestyle and diet, and give up bad habits. If you experience discomfort caused by the blockade, do the following:

Complete heart blocks

Let's look at what a complete intraventricular block caused by pathological changes looks like on an ECG. The amount of damage to each branch of the left leg of His is indicated by the deviation of the isoline towards negative or positive values. It is located neutrally (zero position), when excitation is transmitted to the ventricles in a normal rhythm. When the passage of a pulse is disrupted, broadening is recorded QRS complex, which in some cases reaches more than 0.18 s.

With a significant increase in depolarization caused by conduction disturbances in the His bundle, early. On the electrocardiogram this process is recorded as follows:

Segment ST in the left parts of the chest is shifted below the isoline; prong T takes the form of a negative equilateral triangle.
Segment ST in the right parts of the chest - above the isoline, tooth T with a positive value.

When the right ventricular block occurs, the following occurs:

A low tooth is formed S greater width;
Prong R, on the contrary, narrow, but tall;
QRS the complex is shaped like the letter M.
Secondary repolarization (early) is displayed in the chest leads on the right with a convex upward segment ST, which has a slight downward shift. In this case, the tooth T- with inversion (upside down).

The proximal type of block occurs when the ventricular pacemaker is located in the atrioventricular node. On the ECG this type of blockade is marked by a normal (not widened) complex QRS, the frequency of ventricular contractions is quite high (up to 50 per minute).
In the distal type, the ventricular pacemaker has a lower idioventricular location. It is the bundle of His with all its branches. It is called a third-order automatic center. The electrocardiogram shows that the number of ventricular contractions is reduced, it does not exceed 30 per minute. This is indicated by the broadening of the complex QRS more than 0.12 s and overlap with the ventricular QRS tooth complex R. It may have a changed shape (if the automatic impulse occurs below the point at which the His bundle begins to branch). The ventricular complex retains an unchanged shape if the initial point of localization of the automatic impulse is located in the bundle itself.

Drug therapy for complete blockade

Therapy for complete blockade of any type is carried out based on etiology and pathogenesis.

Radical methods include implantation. Indications for its use are:

low ventricular rate;
increased period of asystole (more than 3 s);
occurrence of MAS attacks;
complete blockade, complicated by persistent heart failure, angina pectoris and other diseases of the cardiovascular system.

Forecast

A favorable prognosis is given only with partial blockades. The development of a complete third-degree block leads to complete disability, especially if it is complicated by heart failure or occurs against the background of myocardial infarction. The implantation of a pacemaker will make it possible to make more favorable prognoses. When used, some patients may experience partial restoration of their ability to work.

Features of heart block localizations

His bundle and its blockade

Sinoatrial heart block

violation of the generation or conduction of impulses at the level of the sinus node

In this case, three stages of its manifestation are distinguished.

At the first stage, the passage of the impulse through the sinoatrial region is delayed. It can only be detected by electrophysiological studies.
At the second stage, two types of SB should be considered. With the development of the first type, a periodic blocking of one impulse occurs at the exit from the atria. Sometimes several impulses in a row are blocked at once, with Weckenbach periodicity. The R-R interval corresponding to the pause is extended. But its value is less than twice the R-R interval that precedes the pause. Gradually, the intervals that follow a long pause become shorter. It is detected during a standard ECG, on which the pulse frequency is displayed without change.
The second type is characterized by a sudden disruption of impulse conduction, in which there are no Weckenbach periods. On the cardiogram, the pause is recorded as doubling, tripling, etc. pauses R-R.
The third stage is a complete disruption of impulse conduction in the atria.

Interatrial block

One of the small rare heart rhythm disorders is interatrial block. Like all other types, it has three stages.

The impulse of excitation is delayed.
Periodic blocking of the excitatory impulse entering the left atrium.
Dissociation of atrial activity or complete conduction disturbance.

Heart block in childhood

Congenital blockade can be caused by the following reasons:

Diffuse damage to the mother's connective tissue.
The presence of type II diabetes mellitus (insulin-dependent) in the mother. This syndrome is called Legerne disease.
Not fully formed right leg of the His bundle.
Anomaly in the development of the interatrial and interventricular septa.
M.Lev disease

Congenital heart blocks often cause the death of a child in the first year of life. In a newborn they are manifested by the following symptoms:

Blueness or cyanosis of the skin, lips;
Increased anxiety or, conversely, excessive lethargy;
The baby refuses to take the breast;
He has increased sweating and...

For mild forms, drug treatment is not required. But the child needs constant monitoring by a cardiologist. In some cases, surgical intervention is recommended, which can save the baby’s life.

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Causes of intraatrial block

Intraatrial block occurs due to excessive strain and degeneration of the atrial muscles. This pathology, in turn, is provoked by:

congenital or acquired heart defects;

atrial fibrosis;

myocarditis;

ischemic disease;

intoxication with cardiac glycosides and other drugs.

Thus, the blockade is not an independent pathology, but a companion to various disorders associated with insufficient blood circulation, etc.

Classification of the disease

There is the following classification of intraatrial block:

First degree. All impulses pass to the atria, but at a reduced speed. Pathology is diagnosed only with an ECG. Usually the patient does not experience any discomfort.

Second degree. At this stage of pathology development, severe disturbances in the conduction of impulses occur.

Third degree (complete blockade). At this stage, the conduction of impulses stops.

Experts identify the following severe complications of blockades.

These include:

progression of heart failure;

deterioration of the patient's condition;

Symptoms of intraatrial block

Symptoms of the pathology depend on the severity of the disease. In the initial stages, the patient may not even realize that he is sick.

In the second degree of pathology, it is usually determined:

fatigue;

dizziness;

weakness;

loss of consciousness

Important! In severe cases of blockade, the prognosis of the pathology is unfavorable. The attack can be fatal.

Diagnosis of intraatrial block

If any signs of pathology occur, you should immediately contact a cardiologist.

Collect anamnesis. The specialist will examine the patient’s condition and get acquainted with concomitant diseases. The doctor will also inquire about the patient’s heredity. This is due to the fact that many cardiovascular pathologies are transmitted from parents to children.

Will order a full examination.

Diagnostics include:

Holter monitoring.

The blockade is characterized by a disturbed rhythm and improper conduction of impulses to the atrium. Monitoring makes it possible to establish the degree of pathology. An examination is also carried out to determine the cause of the disease, since it is not an independent disease.

During the examination, patients also undergo laboratory tests (general and biochemical blood tests).

In some cases, only the most modern techniques can identify the disease. These include EPI, angiography, etc. Such examinations provide opportunities to identify the causes of blockades that occur. The “gold standard” for determining coronary disease, for example, is coronary angiography. It allows you to see all the coronary arteries and determine the degree and location of their narrowing. The results of the study provide opportunities for predicting the course of pathology.

Treatment of intraatrial block

Therapy for blockades largely depends on their degree. The underlying disease should always be treated.

For 1st degree blockade, no special therapy is performed. In some cases, the pathology disappears when the drugs that contributed to its development are discontinued. The patient also benefits from therapy for the underlying disease of the cardiovascular system.

If the blockade is caused by vagotonia, good therapeutic results are achieved by using atropine. The drug is administered subcutaneously or taken in tablet form.

Also, to eliminate pathology, the following is prescribed:

ephedrine and other similar drugs;

inosine, adenosine triphosphoric acid; trimetazidine

Important! Drug therapy in advanced cases is only supportive.

Before starting therapy, you should stop taking:

potassium salts;

drugs for arrhythmia;

cardiac glycosides;

beta-blockers, etc.

If the pathology is accompanied by attacks of asystole or significantly worsens the patient’s condition, they may resort to permanent or temporary stimulation of the atria. In this case, an electrical pacemaker is implanted.

The main indications for installing a stimulator are:

cerebrovascular accident;

heart failure;

high risk of sudden cardiac arrest;

severe bradycardia (less than 40 beats per minute).

Asymptomatic blockade in the initial stages of development usually has a favorable prognosis. Successful therapy can be carried out in advanced cases, it is only important to entrust it to experienced specialists. Therapy prices largely depend on:

degree of development of pathology;

characteristics of the patient's condition;

concomitant diseases and other factors.

The exact price of therapy in our clinic in Moscow will be calculated by our specialist after consultation.

Prevention of intraatrial block

Since heart blocks in most cases are a consequence of pathology of the cardiovascular system, prevention comes down to timely and adequate treatment of the underlying disease.

People who are at risk of developing them should:

carefully monitor the doses of medications taken to avoid overdose;

to refuse from bad habits;

lead a healthy and active lifestyle.

Proper nutrition will also prevent the development of diseases. Avoid fried, fatty foods and canned foods. Be sure to take walks and spend more time outdoors. If you have a history of cardiovascular disease, you should definitely visit a cardiologist regularly. Particular attention should be paid to the state of health if someone close to you has had a heart attack, uses an electrical stimulator, or suffers from ischemia.

The doctor will tell you about all methods of prevention! He will also prescribe medications to maintain health.

Advantages of the clinic

By contacting the IAKI Clinic of Modern Medicine, you can count on:

assistance from experienced doctors;

compliance with medical ethics;

high qualifications of all specialists;

availability of any services.

Each patient will be able to quickly undergo a high-quality examination and receive the attention of staff during treatment. We take a person-centered approach. Each patient is valuable to us, first of all, as an individual, and not as a patient with an interesting medical history or a client who creates the financial well-being of a specialist! Treatment is carried out comprehensively and using the most modern techniques.

In our clinic you do not spend money on therapy, but invest it in your health!

Intraatrial block- This is a violation of the conduction of electrical impulses through the conduction system of the atria.

ECG signs of intraatrial block: widening of the P wave over 0.11 sec and its splitting and deformation of the P wave (double-humped P wave) without increasing its height; in lead V 1, the P wave is widened without a predominance of the negative or positive phase of the wave.

Interatrial (intraatrial) blockade of the first degree. Permanent splitting of the P wave is noticeable

Interatrial (intraatrial) blockade of the second degree. The arrow indicates the moment of maximum conduction blockade.

(splitting of the P II wave and disappearance of the second negative phase of the P V1 wave)

Intraatrial block occurs in patients with acute myocardial infarction, atherosclerotic cardiosclerosis, mitral heart defects, arterial hypertension, acute inflammatory processes in the myocardium (acute rheumatic fever, scarlet fever, diphtheria, influenza, tonsillitis), chronic infections (tuberculosis, syphilis), hypertonicity of the vagus nerve .

21. Name the ECG signs of atrioventricular blockI, II, IIIdegrees.

Atrioventricular block- This is a violation of the conduction of electrical impulses from the atria to the ventricles.

Disruption of the conduction of electrical impulses from the atria to the ventricles can occur in different parts of the conduction system. When there is blockade at the level of the atria, AV node or main trunk of the His bundle, they speak of proximal atrioventricular block. If the delay in impulse conduction occurs at the level of all three branches of the His bundle (the so-called trifascicular, or three-fascicular block), this indicates distal atrioventricular block.

There are 3 degrees of atrioventricular block.

Atrioventricular blockI degree– P-Q interval is more than 0.2 seconds, the same in all cardiac cycles, with normal P wave duration; a P wave precedes each QRS complex; there is no periodic loss of ventricular QRS complexes; the ventricular complex is not changed.

1st degree AV block (nodular form)

Atrioventricular blockII degree characterized by periodic loss of ventricular complexes due to blockade of the sinus impulse in the atrioventricular junction. As a result, only the P wave is recorded on the ECG, and the following ventricular QRST complex is absent; the number of atrial contractions (number of P waves) is always greater than the number of ventricular QRST complexes, and the ratio of atrial and ventricular rhythms is designated 2:1, 4:3, 3:2, etc. With a 2:1 atrioventricular block, every second ventricular complex is lost, and with a 3:1 block, two QRST complexes in a row are lost.

There are three main types of atrioventricular block of the second degree: type I (Mobitz type I or with Samoilov-Wenckebach periodics), type II (Mobitz type II or without Samoilov-Wenckebach periodics), type III (far advanced).

Type I (Mobitz type I). With type I, second degree blockade, there is a gradual, from one complex to another, slowing down of conduction through the AV node, up to a complete delay of one (rarely two or three) electrical impulses.

ECG signs: gradual lengthening of the P–Q(R) interval followed by loss of the ventricular QRST complex; after an extended pause, conduction through the AV node is restored, and a normal or slightly prolonged P–Q(R) interval is recorded on the ECG, after which the entire cycle is repeated again.

Periods of gradual increase in the P–Q (R) interval followed by loss of the ventricular complex are called Samoilov-Wenckebach periods.