Blockade of the heart is a pathological process associated with the impulses of the cardiac system. Blockade of the heart is a very common phenomenon, since the substrate for its occurrence is heart disease. Blockades of the heart can develop in the womb of the mother and be acquired, permanent and transient. Some blockades of the heart may not manifest themselves and "mask" under other diseases.
Complete blockade of the heart is characterized by the termination of excitation from the overlying drivers of rhythm.
Incomplete heart blockage occurs when the impulses are held down by a conducting system. When there is a complete blockade of the heart, asystole does not occur, since the function of the pacemaker takes over the underlying node. As a result, the number of cardiac contractions decreases, and cardiac arrest does not occur. However, often such compensatory work is insufficient, which can lead to heart failure.
Causes of heart failure
In order to understand the cause of the blockade of the heart, it is necessary to understand the structure of the conducting system. The most important formation that produces an impulse is the sinus node. It is located in the upper part of the right atrium, between the areas of confluence into the atrium of the hollow veins. The sinus node contains two types of cells: P cells that have the ability to produce a pulse, and T cells located around the periphery of the sinus node and performing the function of impulse conduction. Normally, the frequency of formation of pulses with a sinus node of 60-80 per min.
From the sinus node, the impulse is distributed to the atria in several ways. The front path, or Bachmann tract, conducts excitation to the anterior wall of the right ventricle and divides into a branch in the atrial septum that moves to the atrioventricular node, and a branch that moves to the left atrium. The middle path, or the Wenckebach path, passes through the interatrial septum. The Torrel path, respectively, the posterior path, passes along the lower edge of the septum between the atria to the atrioventricular node with the spread of fibers to the right atrial wall. The normal propagation of momentum occurs along the paths of Bachmann and Wenckebach, since they are the shortest.
The next "destination" in the movement of excitation is the atrioventricular node, or the Ashot-Tavar node. Its location is in the lower right atrium to the right of the atrial septum. The main task of this formation is to screen out the impulses that come from the atrium. After all, not every impulse from the atrium is formed in the sinus node. Their formation can occur in some parts of the atrium. And also the atrioventricular node does not pass all pulses with a sinus tachycardia with a frequency of more than 200 per minute. The atrioventricular unit itself, together with the bundle of His, can generate excitation with a frequency of 40-60 per min.
The bundle of the Gysus originates from the atrioventricular node (AV node). It consists of two parts: the initial section, which does not come into contact with the contractile myocardium, and the branching part, which participates in the further conduct of the excitations to the ventricles.
The left and right legs of the bundle of His are sent to the ventricles. The left leg of the heart forms two branches - front and back. In the legs of the heart there are fibers of automatism, which are also capable of generating excitation with a frequency of 15-40 per minute.
Purkinje fibers are the ultimate branches of the conduction system of the heart. They permeate the entire myocardium of the ventricles.
Blockade of the heart can arise as a result of conduction disorders.
All heart blockages are divided into:
1. sinoaurikulyarnuyu blockade;
2. blockade within the atria;
3. atrioventricular blockade;
4. ventricular blockade;
5. blockade of the legs of the heart (Feet legs).
Blockade of the heart often cause functional and organic lesions. Organic lesions are myocardial infarction followed by focal or diffuse cardiosclerosis, cardiomyopathies , myocarditis, systemic lesions of the myocardium with the involvement of the conduction system of the heart, amyloidosis, sarcoidosis , tumors, neuromuscular diseases, thyrotoxicosis , diabetes mellitus .
Blockade of the heart can occur with infectious diseases, intoxications, an overdose of cardiac glycosides, novocainamide, quinidine.
Sometimes a heart block can be congenital. For example, atrioventricular blockade of the third degree occurs in 1 out of 25,000 newborns.
Blockade of the right leg of the heart
Blockade of the heart can take place as a blockade of the right leg of the bundle. It manifests itself in delayed impulses or in the absence of excitation in the area of influence of the right leg. Most often, all blockages of the legs of the heart occur in patients with various heart defects, cardiosclerosis, myocardial infarction, hypertensive disease , myocarditis.
Blockade of the heart can be accompanied by the development of paroxysmal supraventricular tachycardia, myocardial infarction. Observed often in males after 40 years.
Blockade of the right leg of the heart is characterized by certain indications of electrocardiography. Such a defeat is very rare and occurs in 0.15-0.2% of all blockades. 50% of cases of blockade of the right leg of the heart in patients of young age are not associated with heart disease.
The clinical picture of blockages of the right leg of the heart, if it develops without a total blockade of the bundle of the Hisnus, is not symptomatic. Complaints of the patient arise against the background of the underlying disease. Diagnosis is carried out using a standard electrocardiographic study, Holter monitoring.
Blockade of the left foot of the heart
The blockade of the left leg of the heart can be total and partial. Complete blockages of the left leg of the bundle of His are found in 0.5-2%, and after 50 years - 9% of cases of heart block. Blockade of the anterior branch of the left foot of the heart accounts for 1-4.5% of cases, the posterior branch - 0.1%. Pathological processes can involve one of the branches of the left leg, and maybe a total blockade.
Blockages of the left leg can be combined with blockages of the right leg, forming a complete blockade of the ventricles. Often, blockages of the left leg of the bundle of His are accompanied by myocardial infarction, which aggravates the hemodynamic disorders of the underlying disease. The symptoms correspond to the main pathology. The patient complains of pressing retrosternal pain, which does not stop after taking nitrates. The patient is accompanied by feelings of fear of death, weakness, sticky sticky cold drops of sweat. When hospitalized, signs of a heart attack are identified.
Heart block of the ventricle
Under the blockade of the ventricle of the heart is meant the blockade of the atrioventricular junction. Atrioventricular heart block can be of three degrees.
The complete blockade of the heart corresponds to the atrioventricular blockade of the third degree. Blockade of the 1st degree is observed in 0.45-2% of people, and over the age of 60 years - in 4.5-14.4%, after 70 years - in 40% of people. The most common block of ventricles of the third degree occurs against a background of myocardial infarction in the region of the atrioventricular junction. All AV-blockades are divided into those born before birth and acquired. With the flow they are divided into acute, transitory, chronic. The severity of impulse conduction is divided into AV-blockades of the 1st degree, II degree with division into Mobitz I, Mobitz II, high degree, and III degree. The clinical picture of AV blockade can be different: they can be asymptomatic, there are random findings on the ECG, fainting develops, coronary and heart failure worsen, there are feelings of pauses and irregularities in the heart.
Heart Blockade Treatment
All antiarrhythmic drugs are divided into several classes. The first class includes drugs that block sodium channels.
Class IA includes drugs Quinidine, Novokainamid, Rhythmelen.
Class IB drugs have a lidocaine-like action: Lidocaine, Diphenin.
Preparations of IC class cause a sharp blockade of sodium channels, they include Ritmonorm, Enkainid, Giluritmal.
II class of antiarrhythmic agents includes beta-blockers: Propranolol, Nadolol, Bisoprolol, Esmolol, Atenolol.
Third-class drugs are drugs blocking potassium channels: Amiodarone, Nibentan, Sotalol.
Class IV antiarrhythmic drugs are medicines that have a depressing effect on the conduction system of the heart. These drugs Verapamil and Diltiazem. But not all these drugs are able to stop the attack of the heart block, and sometimes even provoke this attack of impulse conduction.
Not every type of heart block requires treatment and hospitalization. The blockade of the heart of the sinoatrial is manifested by disturbances in the impulses from the sinus node to the atrium. The patient feels a break in the work of the heart, there is a bradycardia in this case.
Treatment of the sinoatrial heart block is the same as in sinus bradycardia. Depending on the degree of cardiac blockade, medication is prescribed. With incomplete sinoatrial blockades (I-II degrees), the patient complains of fading, heart failure, tinnitus and headaches . Blockade of the heart III stage, or complete blockade of the heart, requires urgent therapy, since the bradycardia, which developed in this case, is insufficient for blood supply of all organs and tissues. With incomplete blockade of the heart, use Atropine 0.1% solution in a dose of 1.0 ml intravenously. The total dose of this drug should not exceed 0.04 mg per kg. Alupent 0,05% solution in a dose of 1 ml intravenously with dilution in physiological solution at a rate of 8 drops per minute.
If a complete heart block has developed, or a sinoatrial blockade of the third degree, then more aggressive therapy is prescribed: Dopamine in a dose of 5-10 μg / kg per min. when diluted in a solution of glucose 5%, the rate of administration is 10-20 cap per min. Dopamine administration should be carried out in conjunction with ECG control, as tachycardia can develop until the ventricular fibrillation. Instead of Dopamine, you can use Adrenaline, whose concentration is 0.1%, with a dilution of 1 mg in 250 ml of a 5% glucose solution, at a rate of 10-20 capp / min. In the absence of the effect of drug therapy, it is necessary to carry out electrocardiostimulation on its background. In the subsequent, resort to installation of the artificial driver of a rhythm.
AV-blockade of the 1st degree without clinical manifestations does not require treatment. Sometimes such a blockade of the heart occurs in athletes of high category.
AV blockade II degree Mobitz type I does not need drug treatment, if there are no clinical symptoms. If there is a violation of hemodynamics, then appoint Atropine 0.1% solution in a dose of 1 ml. If atropine is ineffective, then cardiostimulation is performed against it.
If the heart block has occurred against the background of myocardial infarction, then in the tissues exceed the adenosine, which is derived adenosine antagonists - Adenophylline, or Eufillin. A far-reaching blockade of the second degree requires monitoring of the patient and reception of conductivity improving agents.
With complete blockade of the heart, cardiac pacemaking is used for the following indications: acute heart failure, manifested by pulmonary edema, arterial hypotension, arrhythmogenic collapse; occurrence or aggravation of myocardial ischemia; fainting attacks, especially at rest; development of blockade during resuscitation; blockade as a consequence of an acute disease. In other cases, pharmacotherapy is used. Some drugs can stop the blockade of the heart, others - cause a rapid increase in the ventricular rhythm. But the purpose of these funds is one - to maintain stable hemodynamics.
Before taking medication, you should cancel preparations that slow down the conductivity. These include beta-blockers, cardiac glycosides, potassium preparations, calcium channel blockers.
The next step in the treatment is the appointment of anticholinergics: Atropine at a concentration of 0.1% by a dose of 1 ml intravenously, but not more than 0.04 mg / kg. Adrenomimetics, or stimulants of adrenaline receptors, are not so effective in blockade of the heart. They increase myocardial oxygen consumption and promote the development of a more serious arrhythmia. Their use is justified only if there is no possibility of cardiac stimulation. Dopamine in a dose of 5-20 mkg per kg per min. is administered intravenously at a rate of 10-15 drops per minute. Adrenaline - 0.1% - 1 ml intravenously. But drugs such as Dopamine and Adrenaline are a therapy of despair. Therefore, it is recommended to use other drugs: Ephedrine in a dose of 1 ml of a 5% solution of IV and / or Alupent in a dosage of 1 ml-0.05% solution dissolved in 200 ml of physiological solution at a rate of administration of 8 drops in min. It is possible to administer isoproterinol 0.5% and 1% in a dose of 1 ml per 250 ml of glucose at a rate of 20 cap per min.
It is not contraindicated in the case of AV blockade, a potassium-sparing diuretic. Hypothiazide in a dosage of 100 mg once a day for 3-5 days. Sodium bicarbonate is administered intravenously in a dose of 100 ml of a 4% solution. Soda should be administered slowly, within 30 minutes, since ventricular fibrillation may occur.
In the event of a prolonged fainting fit, a jerky 2-3 strokes with a compressed fist in the over-cardiac region and an indirect cardiac massage are performed, followed by electrical cardiac stimulation. In the event of a constant onset of fainting attacks, permanent pacemakers are used.
Surgical treatment is the main method of treatment of AV blockade. It should be taken into account the fact that blockades of higher localization are constant, and heart blockages on the lower sections of the conducting system tend to progress. Indications for the installation of a permanent pacemaker are divided into classes. The first class includes the following conditions: AV-blockade of the third degree or rapidly progressing blockade of the II degree of any level, if it is combined with a symptomatic bradycardia, with arrhythmia, asystole for 3 seconds, with heart rate less than 40 beats per minute. Also, the first class of indications is the state after catheter ablation of the AV node, with neuromuscular diseases involving AV connection, AV blockade with bradycardia.
Class IIa includes asymptomatic cardiac arrest of III century. regardless of the place of origin at an average heart rate of more than 40 per minute in the waking state, especially with the expansion of the heart boundaries and the non-stable function of the left ventricle. This class includes asymptomatic AV blockade of the II degree of Mobits II and I type, as well as severe blockade of I and II degrees.
Class IIb includes AB-blockade I degree in patients with unsatisfactory left ventricular function and symptoms of hemodynamic failure, neuromuscular diseases with AV blockade of any st.
Patients who underwent myocardial infarction are implanted with a pacemaker with a stable blockade of II - III degree. With the manifestation of AV blockade II - III st. in the acute period of myocardial infarction, the introduction of a temporary pacemaker is shown. In connection with the fact that a repeated conduction disorder may occur, the installation of a permanent pacemaker should be delayed.
Treatment of conduction disorders in the heart of the heart begins with the definition of indications for hospitalization. If necessary, the selection of antiarrhythmic therapy and the planned pacemaker patient must be hospitalized. Treatment begins with the correction of electrolyte disorders. Should be abandoned cardiac glycosides, beta-adrenoblockers, calcium channel blockers, quinidine, novocainamide, rhythmelin, rhythm monomer.
Drug therapy consists in the appointment of Bellooid for 1 dragee 3-4 r. in d. He has an atropine-like effect and relieves bradycardia. Contraindication is glaucoma. Theophylline in a dose of 0.1 g 2-3 r. in d. It is used to improve the tone of the heart. Allapinin in a dose of 25 mg every 8 hours before meals. In most patients with blockade, panic attacks appear, which should be suppressed with clonazepam in tableted form at 5 mg 2-3 r. in a day. within 3-5 days. Before taking medication, you need to consult a doctor, because there are side effects.
Surgical treatment involves the implantation of a pacemaker when blocking two and three beams. Also, an indication for a constant stimulant is myocardial infarction with a heart blockade.
When treating disorders of the conduction system of the heart, you can use folk remedies. They will create a favorable background for therapy. One of the useful plants for this is the rosehip. When brewing 5 tbsp. l. its fruit in ½ liter of water. Mash cooked fruits with honey and pour into the resulting broth. If you drink such a decoction before eating for ¼ cup, then the condition will improve.
The horsetail can also have beneficial effects on the cardiovascular system. You need to brew it in a glass of water in the amount of two teaspoons. To consume 1 tbsp. spoon every 2 hours.
Broth from the roots of valerian for one st. spoon every time before eating. Has a calming effect, which is important for diseases of the cardiovascular system.
Motherwort, yarrow, cornflower well influence the conduct of the impulse.
A major role in the treatment of heart blockages is also played by the restoration of the normal regime of the day, adequate sleep, the right way of life, the restoration of normal cholesterol and fat in the blood. With the normalization of these indices, the atherosclerotic process regresses. In 70% of the smoking population, the risk of an atherosclerotic lesion is higher than that of non-smokers. For the prevention of cardiosclerotic process, it is necessary to start treatment of myocarditis, chronic infections, rheumatic fever in time.