Blockade of the heart - Causes, symptoms and treatment. MF.

In order for the heart to supply blood to every cell of the body, it must contract in the right rhythm and at a frequency of 55-60 to 80-90 beats per minute. The rhythm should be regular, with the same intervals between contractions, because the absence of oxygen carried with blood, even for more than 30 seconds, can already affect the functioning of cells, and primarily of brain cells. The occurrence of oxygen starvation( hypoxia) of the brain is especially important for conditions such as heart block.

Heart blockages are related to heart rhythm disturbances, or arrhythmias. Arrhythmias can be characterized by an increase in heart rate( tachycardia and tachyarrhythmia) and a decrease in( bradycardia, bradyarrhythmia).

Heart blockades is a group of diseases characterized by a slowing down of the electrical signal on the heart, resulting from congenital features or, more often, diffuse substitution of normal muscle tissue of the heart for scar( connective).In general, blockades lead to the development of a bradycardia with a frequency of less than 50 per minute, but can also be combined with a rapid irregular pulse, for example, in the case of Frederic syndrome, a combination of atrial fibrillation and complete atrioventricular blockade. The danger of complete blockade is that the absence of electrical excitation of the ventricles leads to the absence of their contraction in the time interval from several milliseconds to several minutes, which is fraught with the development of brain hypoxia, loss of consciousness and clinical death.

The development of blockades in this or that disease is explained by the fact that the parts of the conduction system of the heart are often involved in the pathological process. These are altered muscle cells, whose main task is to conduct an electrical signal so that a wave of excitement regularly passes through the heart. If these cells are exposed to inflammation, are trapped in scar tissue, or can not transmit a pulse to the cells further downstream, a block appears in the path of the impulse transmission.

Depending on which part of the cardiac conduction system is involved in the pathological process, the following blockages are identified:

- sinoauricular( sinoatrial) - when the sinus node is blocked in the right atrial auricle,
- intracentric blockade - when the path of the electric impulse along the wallsatrial,
- atrioventricular - in the block of the node that "switches" excitation from the atria to the ventricles,
- intraventricular blockade, or blockade of the left and right Leg legs. It is complete and incomplete;one-, two- and three-beam. With the help of a bundle of Gis in the walls of the ventricular myocardium, excitation is uniformly transmitted along their walls, causing rhythmic contractions of the heart.

Depending on how impaired the conductivity of the pulse is, partially or completely, complete and incomplete blockages are distinguished.

Blockade I - II degree is incomplete, and III - complete. In the first case, not all conductive fibers are affected, so part of the impulses are conducted to the lower part of the myocardium. With complete blockade, impulses are not carried out at all, therefore, the reduction of the lower regions is carried out either at the expense of ectopic( elsewhere) foci of excitation, or not at all.

The prevalence of heart blockage varies and depends on age. Thus, atrioventricular blockade of the first degree in young people occurs in 1% of cases, and in elderly people - in 2.4%.Blockade II degree in young people occurs in 0.003% of cases, and increases in the elderly. Congenital atrioventricular blockade of grade III is extremely rare - in one case, 20,000 live births. Blockade of the right leg of the gypsis occurs in 2 - 5% of healthy individuals, and in the absence of severe cardiac pathology may be a variant of the norm.

Causes of blockade of the heart

Blockade of the 1st degree and incomplete blockade of the Hypos that do not appear clinically may be a variant of the norm or occur in athletes, in persons with vegetative-vascular dystonia, as well as in children, adolescents and young adults with mitral valve prolapse, an open oval window and other small anomalies in the development of the heart.

Block II and III degree, complete intraventricular blockade, three-beam blockade( both the right and both branches of the left leg of the Hisnus) almost always occur with organic damage to the heart tissues. The diseases that cause inflammation or scarring in the myocardium include:

1. Myocarditis - inflammation of the heart muscle caused by:
- viral infections - Coxsackie, rubella, measles, Epstein-Barr( infectious mononucleosis), influenza, adenovirus, cytomegalovirus
- bacterial and parasitic infections - rheumatic fever, diphtheria, scarlet fever,toxoplasmosis, systemic chlamydiosis
- autoimmune diseases - rheumatoid arthritis( 5-25% of patients have heart disease), systemic lupus erythematosus( 5-15%), systemic scleroderma( 20-40%)
2. Cardiomyopathy is a group of diseaseswith a pathological change in the normal anatomical structure of the heart( a significant thickening of the walls of the heart or vice versa, their thinning with the expansion of the internal cavities of the heart, preventing them from normally contracting and relaxing).They can develop with coronary heart disease, arterial hypertension, imbalance of hormones in the body, toxic effects of alcohol, drugs, metabolic disorders, myocarditis.
3. Cardiosclerosis - scarring of muscle tissue involved in the inflammation zone or in the area of ​​necrosis( death) of the myocardium after myocardial infarction.
5. Acute myocardial infarction - in 15% of patients there are conduction disorders.
6. Congenital and acquired heart defects.
7. Intoxication with cardiac glycosides, betta - blockers, which cut heart rate.
8. Arterial hypertension often causes conduction disturbances inside the atrial heart.

Symptoms of cardiac blockade

Blockades of the 1st degree, incomplete single-bundle blockade of the legs of the Hisnia, intracirculatory blockade, as a rule, do not manifest themselves clinically and can be detected only by ECG in a planned examination.

Complete blockade is manifested by the symptoms of arrhythmia and signs of the underlying disease. These clinical manifestations can occur suddenly, against a background of good health, but can exist for a long time, with periods of deterioration, to which the patient has adapted and "learned" not to pay attention to them. However, if you notice some of these symptoms, you should consult your doctor for a checkup, because some symptoms may be a sign of impending dangerous conditions.

Symptoms of rhythm disturbance:

- weakness, fatigue, reduced ability to perform the previous physical work,
- a feeling of heart failure - a sense of fading or cardiac arrest, discomfort behind the sternum,
- dizziness, flies before the eyes, sudden general weakness withsensation of faintness, tinnitus,
- seizures of Morganyi - Edessa - Stokes( MES attacks) - sudden sharp pallor, cold sticky sweat, threadlike rare pulse, loss of consciousness, possible convulsions due to hypoxia of the brain. As a rule, after a few seconds or two - three minutes, consciousness is restored, but if this did not happen, and breathing and palpitation are absent, then the asystole( stopping) of the heart and clinical death,
- the left left bundle of the bundle of Guiss, developed suddenly for the first time inlife can lead to the development of acute left ventricular failure with pulmonary edema, which is characterized by choking, coughing with phlegm similar to foam, blue skin of the lips, face, fingers, shock state.

Symptoms of the underlying disease - pain in the chest during physical activity or at rest with ischemic heart disease, dyspnea, coldness of the hands and feet, cyanosis of the fingers, nose, ears or the whole face and limbs in the heart defects, headaches of the occipital localizationwith nausea and vomiting in hypertension, high temperature or prolonged temperature increase not higher than 37.5º С for infections, joint and skin damage in systemic diseases and many others.

Diagnosis of heart blockade

The doctor can think about the preliminary diagnosis even when clarifying the nature of the patient's complaints. For further diagnosis, the following methods are used:

- the standard ECG - the main informative method that confirms the presence of a blockade. Nevertheless, a single electrocardiogram may not always "catch" the signs of blockade, especially in the case of transient cardiac blockages.

Symptoms of sinoatrial blockade - periodic loss of P-QRS complexes due to the fact that not every pulse from the sinus node reaches the atria, and hence, the ventricles. Increasing the RR interval in two, and sometimes more times.

Symptoms of intracorporeal blockade - cleavage and expansion of more than 0.11 from the P wave, and the associated lengthening of the PQ interval. Sometimes there is an additional negative tooth P( with complete dissociation of the right and left auricles and their contractions in a separate rhythm).

Symptoms of atrioventricular blockade of the 1st degree - constant elongation of the PQ interval more than 0.20 s, type II of the type Mobits 1 - with each subsequent contraction, the PQ interval becomes longer until one cardiac complex P-QRS is dropped, then the entire cycle is repeated again. Blockade II degree as Mobits 2 - the duration of the interval PQ in each contraction is equally elongated more than 0.20 s, and the ventricular complexes QRS fall randomly, without a clear periodicity and can be deformed. Blockade II degree 3 type - there is no every second or two or more complexes P-QRS in a row. Blockade III degree - complete separation of the rhythm of the atria and ventricles - the frequency of atrial contractions - 70 - 80 per minute, ventricles - 40 - 50 per minute or less. Atrial pts P are not associated with QRS ventricular complexes, can overlay, be before or after them.

Signs of intraventricular blockade: with incomplete blockades - QRS complex is not expanded, not deformed, changes in the R wave( expanded and serrate) and S-wave in the left or right leads are observed, respectively, in the blockade type( right or left);in case of complete blockade - extended deformed QRS complexes wider than 0.12 s, wide deep tooth S in the corresponding leads( III, aVF, V 1,2 for right blockade, I, aVL, V 5, 6 with left blockade).

Complete left bundle bundle bundle

- 24-hour ECG monitoring is informative for transient blockages, as it allows analyzing the heart rhythm and conductivity throughout the day, including at night.
- ECG with exercise is used to determine tolerance to physical activity, it allows to establish a functional class of coronary heart disease and chronic heart failure.
- echocardiography, chest X-ray, MRI of the heart, coronary angiography are used to find the underlying disease that caused conduction disorders.

Treatment of heart blockade

Blockade therapy begins with the treatment of the underlying disease. Blockade I degree, not manifested clinically, treatment does not require.

In overdose with drugs that slow down the rhythm, a complete cancellation of these drugs is carried out. For blockades of the heart, betta-blockers( propranolol, bisoprolol, atenolol, anaprilin, tenorik, obzidan, egilok, etc.), cardiac glycosides( strophanthine, korglikon, digoxin), antiarrhythmic drugs( aymalin, cordarone, verapamil, diltiazem, quinidine) are contraindicated.

With functional blockades associated with vascular dystonia, small heart abnormalities, sports, with sinoatrial scrapes of I - II degree and intracardiac blockades, drugs improving the metabolism in the cardiac muscle - ATP, riboxin, vitamins, antioxidants( ubiquinone, mexidol, actovegin).

Complete atrioventricular blockade is treated with the appointment of isoprenaline and orciprenaline by the course, after which the question of implantation of an artificial pacemaker is solved.

There are no specific drugs for the treatment of intraventricular blockade. In severe cases( full right or left blockade in the background of acute myocardial infarction, two- and three-beam blockades, especially with MES attacks), temporary or permanent cardiac pacing is used.

First aid for cardiac blockade

As first aid in a patient with MES attacks, 1 to 2 tablets of isadrin under the tongue( 5 to 10 mg), subcutaneous administration of atropine, intravenous injection of epinephrine, noradrenaline are shown. In the absence of breathing and cardiac activity - indirect cardiac massage and artificial respiration before the arrival of an ambulance.

In the case of clinical death, the ambulance team carries out cardioversion( rhythm restoration) with the help of an electrical discharge from the defibrillator and emergency hospitalization in the intensive care unit to further address the implantation of an artificial cardioverter-defibrillator in the heart.

Non-steroidal anti-inflammatory drugs, glucocorticoids( prednisolone, hydrocortisone), penicillin antibiotics, diuretics( diuretics), antihypertensive drugs( enalapril, perindopril), aspirin to reduce thrombosis in the blood stream and on the heart wall, drugs normalizing the levelcholesterol in the blood( statins), etc.

Lifestyle with heart block

Lifestyle is reduced to the correction of nutrition with an increase in the diet of proteins, vegetable fats and complex carbohydrates and restricting animal fats and simple carbohydrates, reducing significant physical exertion, the correct organization of the regime of the day with sufficient rest.

A child with a congenital or acquired heart block will not be able to lead a lifestyle that is normal for children of his age, since physical education, visits to sports clubs and sections and any significant workloads will be prohibited to him. A young man with a blockade of II degree and higher, most likely, will not be fit to serve in the army. The issue of bearing pregnancy for women is decided strictly individually, with the participation of doctors of a cardiologist, cardiac surgeon, obstetrician-gynecologist and other specialists in the consultation.

Obligatory is the timely access to the attending physician with the growth of unpleasant symptoms and a significant deterioration of well-being. A patient with a blockade should take responsibility for his disease responsibly and understand that a high-level blockade can end fatal at any moment. In order that this does not happen, you should carefully consider your health, listen to the advice of doctors and strictly fulfill their diagnostic and therapeutic purposes.

Complications of the heart block

Complications include:
- progression of the blockade, for example, AB - blockade of 1 degree often progresses to blockade of the 2nd degree of the 1st type, rarely - until the complete AV blockade. In this regard, it is important to monitor the patient with ECG monitoring of the patient. Originally AV-blockade II degree II type often progresses to complete blockade.
- complications of complete blockade - acute left ventricular failure with pulmonary edema, ventricular asystole and sudden death.
is the progression of chronic heart failure.
- pulmonary thromboembolism, myocardial infarction, ischemic stroke.

Prevention is the competent drug treatment of the underlying disease, the timely determination of indications for the implantation of a pacemaker.

Forecast

The prognosis for blockades of I degree in the absence of organic damage to the heart is favorable.
For complete blockades, the prognosis is determined by the nature of the underlying disease, the degree of impaired cardiac function, and the stage of chronic heart failure. The frequency and number of MES seizures are not predictors of mortality, that is, they do not affect the prognosis - in some patients seizures may occur frequently, while in others, a single attack in a lifetime can lead to death.

The prognosis for patients in the acute period of myocardial infarction, complicated by the development of a complete left or right blockade of the bundle of His, is extremely unfavorable.

Doctor therapist Sazykina O.Yu.