Heart block - a pathological process associated with the conducting system of the heart pulses.Heart block is very common phenomenon, as a substrate for its occurrence are heart disease.Heart block may develop in the womb, and be acquired, permanent and transient.Some heart block may not manifest itself and "masked" by other diseases.
Complete heart block is characterized by the cessation of the excitation from the overlying pacemakers.
Incomplete heart block occurs during deceleration of pulses on a conductive system.When a complete heart block, asystole is not the case, since the functions of the pacemaker takes over the underlying node.The result is a reduction in heart rate and cardiac arrest occurs.Often, however, such compensatory work is insufficient, which can lead to heart failure.
Heart block causes
In order to understand the cause of the heart block, you must understand the structure of the conducting system.The most important entity that produces the impulse is
From the sinus node impulse to the atria is distributed in several ways.Front path, or path Bachmann, holds excitement to the front wall of the right ventricle and the atrial septum is divided into a branch, which moves to the atrioventricular node, and the branch that is moving to the left atrium.Middle way, or Wenckebach path, passes through the atrial septum.Tract torreglia respectively rear path runs along the bottom edge of the septum between the atria to the atrioventricular node with the spread of fiber to the wall of the right atrium.The normal distribution of the momentum going in the ways of Bachman and Wenckebach, as they are the most short.
next "destination" in the movement of excitation is the atrioventricular node, the node or Aschoff-Tawara.Its location is in the lower right atrium to the right of the atrial septum.The main objective of this education is sifting impulses that come from the atria.It's not every impulse from the atria are formed in the sinus node.Their formation can occur in some sections of the atria.As well as the atrioventricular node does not pass all the impulses in the sinus tachycardia with a frequency of 200 per minute.Himself atrioventricular node together with bundle branch block can generate excitement with a frequency of 40-60 per minute.
bundle of His originates from the atrioventricular node (AV node).It consists of two parts: an initial division, which is not in contact with the contractile myocardium, and branching department, which is involved in the further conduction of excitation to the ventricles.
right and left bundle branch block are sent to the ventricles.The left leg of the heart forms two branches - the front and rear.The legs are the fibers of the heart automaticity, which are able to generate excitement with a frequency of 15-40 per minute.
Purkinje fibers are the final branches of the conduction system of the heart.They permeate the entire ventricular myocardium.
Heart block can occur as a result of conduction disturbances.
All heart blocks are divided into:
1. sinuauricular blockade;
2. blockade within the atria;
3. atrioventricular block;
4. ventricular blockade;
5. blockade heart legs (legs-branch block).
heart block often cause functional and organic lesions.Organic lesions - a heart attack, followed by focal or diffuse cardiosclerosis, cardiomyopathy, myocarditis, myocardial system with the involvement of the conduction system of the heart, amyloidosis, sarcoidosis, tumors, neuromuscular disease, hyperthyroidism, diabetes mellitus.
heart block can occur when infectious diseases, poisonings, overdose of cardiac glycosides, novokainamidom, quinidine.
sometimes heart block may be innate.For example, third degree atrioventricular block occurs in 1 in 25,000 births.
blockade of the right leg of the heart
Heart block can pass as a right bundle branch block.It appears slow pulse or lack of excitement on the area of influence of the right leg.Most often, all the legs of the blockade of the heart occur in patients with various heart diseases, cardiosclerosis, myocardial infarction, hypertension, myocarditis.
Heart block may be accompanied by the development of paroxysmal supraventricular tachycardia, myocardial infarction.Frequently observed in males over 40 years.
blockade of the right leg of the heart characterized by certain indications of electrocardiography.This defeat is very rare and occurs in 0.15-0.2% of all closures.50% blockade of the right leg of the heart in young patients are not associated with heart disease.
clinical picture blockade of the right leg of the heart, if it develops without total bundle branch block, does not manifest symptomatically.Complaints arise on the background of the patient's underlying disease.Diagnosis is made through a standard electrocardiography, Holter monitoring.
blockade of the left leg of the heart
blockade of the left leg of the heart can be total and partial.Complete left bundle branch block occurs in 0.5-2%, and after 50 years - 9% of heart block.Blockade of the front branch of the left leg of the heart has to 1-4.5% of the cases, the posterior branch - 0.1%.In pathological processes involved may be one of the branches of the left leg, and perhaps a total blockade.
blockade of the left leg can be combined with the blockade of the right leg, forming a complete blockage of the ventricles.Often left bundle branch block accompanied by myocardial infarction, which exacerbates the hemodynamic disorder underlying disease.Symptoms consistent with the main pathology.The patient complains of oppressive chest pain that does not stop after taking nitrates.The patient was accompanied by fear of death, weakness, are the sticky cold sweat.If you detect signs of a heart attack hospitalization.
Under blockade ventricle understood atrioventricular block connection.Atrioventricular heart block can be three degrees.
complete heart block corresponds to atrioventricular block III degree.The blockade of I degree seen in 0,45-2% of people 60 years and older - from 4,5-14,4% after 70 years - 40% of people.The most common ventricular block III degree against a background of myocardial infarction in the atrioventricular connection.All AV block is divided into arisen before the birth and acquired.Adrift, they are divided into acute, transient, chronic.According to the severity of the violation pulse divided into AV block I degree, II degree of division on Mobitts I, Mobitts II, a high degree, and III.The clinical picture of AV block may be different: they may be asymptomatic, are incidental findings on ECG, develop fainting, compounded by coronary and cardiac insufficiency, there are sensations pauses and interruptions in the work of the heart.
Heart Block Treatment
All antiarrhythmic drugs are divided into several classes.The first class includes drugs that block sodium channels.
Class IA includes drugs quinidine, procainamide, Ritmilena.
Class IB drugs have lidokainopodobnym action: Lidocaine, Difenin.
class IC drugs cause a sharp blockade of sodium channels, these include Ritmonorm, encainide, Giluritmal.
II class of antiarrhythmic agents include beta-blockers propranolol, nadolol, bisoprolol, esmolol, atenolol.
Equity Class III - are drugs that block potassium channels: Amiodarone, Nibentan, sotalol.
Class IV antiarrhythmic drugs - a medication that has a depressing effect on the conduction system of the heart.This drugs verapamil and diltiazem.But not all of these drugs can stop an attack of heart block, and sometimes even provoke this attack a violation of the pulse.
Not every type of heart block in need of treatment and hospitalization.Heart block sinoatrial manifested disorders of impulse conduction from the sinus node to the atrium.The patient feels the stoppage of the heart, while bradycardia occurs.
Treatment sinoatrial heart block is the same as with sinus bradycardia.Depending on the degree heart block is assigned medication.When incomplete sinoatrial block (I-II degree) the patient complains of fading, heart failures, tinnitus and headaches.Heart Block III AH., Or complete heart block requires emergency treatment as bradycardia, which evolved at the same time, insufficient blood supply to all organs and tissues.When partial heart block atropinize 0.1% solution in a dose of 1.0 ml intravenously.The total dose of the drug should not exceed 0.04 mg per kg.Alupenta 0.05% solution in a 1 ml dose intravenously at a dilution in physiological saline at 8 drops per minute.
If developed complete heart block, or sinoatrial block third degree, then prescribe a more aggressive treatment: Dopamine at a dose 5-10mkg per kg per min.at a dilution in 5% glucose solution, the rate of administration is 10-20 min cap.Introduction of dopamine should be held in conjunction with the ECG control, as can develop tachycardia until ventricular fibrillation.Instead of dopamine can be used Adrenaline concentration is 0.1% at a dilution of 1 mg in 250 ml of 5% glucose solution at a rate in drip administration 10-20 min.In the absence of the effect of drug therapy on her background should be carried out pacing.Subsequently, resort to installing artificial pacemaker.
AV blockade degree I, without clinical manifestations does not require treatment.Sometimes, the heart block occurs in athletes high category.
AV block type II degree Mobitts I does not require drug treatment, if no clinical symptoms.If an abnormality is hemodynamic the atropine administered 0.1% solution in a 1 ml dose.With the ineffectiveness of Atropine, then his background perform pacing.
If heart block occurred on the background of myocardial infarction, the tissues exceed the numbers of adenosine, which is derived adenosine antagonists - Adenofillinom or aminophylline.An advanced degree of block II requires monitoring of the patient and improves the conductivity of the reception means.
With complete blockade of cardiac pacing is used in the following indications: acute heart failure, manifested by pulmonary edema, hypotension, arrhythmogenic collapse;the emergence or aggravation of myocardial ischemia;fainting episodes, particularly in rest;the development of the blockade during resuscitation;the blockade as a result of acute illness.In other cases, use of pharmacotherapy.Some drugs can arrest the heart block, others - to cause increased frequency of ventricular rate.But the purpose of these funds alone - to maintain stable hemodynamics.
Before taking medication, should be abolished drugs that slow conduction.These include beta-blockers, cardiac glycosides, potassium supplements, calcium channel blockers.
next step in the treatment is the appointment of anticholinergics: Atropine at 0.1% dosage of 1 ml intravenous, but not more than 0,04mg / kg.Agonists or stimulators of adrenalin receptors, are not as effective in heart block.They increase myocardial oxygen consumption, and promote the development of more serious arrhythmias.Their use is justified only when there is no possibility of pacing.Dopamine at a dose of 5-20 micrograms per kilogram per minute.administered intravenously at a rate of 10-15 drops per minute.Adrenaline - 0.1% - 1 mL intravenously.But drugs such as dopamine and adrenaline - this therapy despair.Therefore recommended to use other drugs: Ephedrine dose of 1 ml of a 5% solution w / w and w / o or alupenta a dosage of 1 ml of 0.05% solution dissolved in 200 ml of saline at a rate of introduction 8drops per minute.Perhaps the introduction of 0.5% Izoproterinola th and a 1% dose of 1 ml per 250 ml glucose at 20 drip min.
not contraindicated in AV block potassium-sparing diuretic.Hydrochlorothiazide in a dose of 100 mg once a d. For 3-5 days.Sodium bicarbonate is administered intravenously at a dose of 100 ml of a 4% solution.Soda must be administered slowly over 30 minutes as ventricular fibrillation can occur.
If there is a prolonged seizure unconscious, made jerky 2-3 clenched fist blow on nadserdechnoy area and chest compressions, followed by electrical pacing.In the case of continuous occurrence of fainting attacks, apply permanent pacemakers.
Surgery is the main treatment for AV block.It should be noted that the blockade of higher localization is constant, and the blockade of the heart to the lower parts of the conduction system prone to progression.Indications for the installation of permanent pacemaker are divided into classes.The first class includes the following states: AV block III degree or rapidly progressive blockade II extent of any level, if it is combined with symptomatic bradycardia, arrhythmias, asystole for 3 seconds, with episodes of heart rate less than 40 beats per minute.There is also a first class readings include state after catheter ablation of the AV node, in neuromuscular diseases involving the AV connection, AV block with bradycardia.
Class IIa includes asymptomatic heart block III century.regardless of the place of origin with the average heart rate over 40 minute in the waking state, especially when expanding the boundaries of the heart and not stable left ventricular function.This class includes asymptomatic atrioventricular block II degree Mobitts type II and I, as well as difficult the blockade of I and II degree.
Class IIb include AV block of I degree in patients with poor left ventricular function and symptoms of hemodynamic failure, neuromuscular diseases with AV block any item.
patients who have suffered myocardial infarction, pacemaker implanted under the counter blockade II - III degree.When the manifestation of AV block II - III Art.in acute myocardial infarction demonstrated implementation of the temporary pacemaker.Due to the fact, that could happen again conduction disturbances, with the installation of a permanent pacemaker should be postponed.
Treatment of conduction disorders in the legs of the heart begins with the definition of indications for hospitalization.When the required selection of antiarrhythmic therapy and planned pacing the patient need to be hospitalized planned.Treatment begins with correcting electrolyte abnormalities.It should give up the cardiac glycosides, beta-blockers, calcium channel blockers, quinidine, procainamide, ritmilena, ritmonorma.
Drug therapy is the appointment Belloidum 1 tablet 3-4 p.in the village. It has the effect of atropine and removes bradycardia.Contraindication is glaucoma.Theophylline in a dose of 0.1 g of p 2-3.in the village. It is used to improve the tone of the heart.Allapinin 25 mg every 8 hours before eating.The majority of patients in case of blockade panic attacks appear to be cut short in tablet form clonazepam 5 mg 2-3 p.per day.within 3-5 days.Before taking this medication should consult a doctor, as there are side effects.
Surgical treatment involves implanting a pacemaker blockade of two and three beams.It is also an indication for permanent pacemaker is a heart attack on a background of heart block.
the treatment of disorders of the conduction system of the heart can be used folk remedies.They will create a favorable background for therapy.l.