Arrhythmia – any violation of a regularity or frequency of a normal warm rhythm, and also electric conductivity of heart. Arrhythmia can proceed asymptomatically or be felt in the form of heartbeat, dying down or interruptions in work of heart. Sometimes arrhythmias are followed by dizziness, faints, heartaches, feeling of shortage of air. Arrhythmias are distinguished in the course of fizikalny and tool diagnostics (an auskultation of heart, the ECG, ChPEKG, holterovsky monitoring, load tests). In treatment of different types of arrhythmias medicamentous therapy and cardiac methods is used (RChA, installation of an electropacemaker, kardioverter-defibrillator).
The term "arrhythmias" emergence, various on the mechanism, manifestations and the forecast of disorder of origin and carrying out electric impulses of heart unite. They result from violations of the carrying-out system of heart providing the coordinated and regular reductions of a myocardium – a sinusovy rhythm. Arrhythmias can cause heavy violations of action of the heart or functions of other bodies, and also to be complications of various serious pathologies. Sinking heart, weakness, dizziness, pains or pressure in a breast, short wind, faints is shown by feeling of heartbeat, interruptions. In the absence of timely treatment of arrhythmia cause stenocardia attacks, hypostasis of lungs, a thrombembolia, an acute heart failure, cardiac arrest.
According to violation of conductivity and a warm rhythm in 10-15% of cases are a cause of death from heart troubles. The specialized section of cardiology – arrhythmology is engaged in studying and diagnosis of arrhythmias. Forms of arrhythmias: tachycardia (tachycardia more than 90 . in min.), bradycardia (urezhenny heartbeat less than 60 . in min.), premature ventricular contraction (extraordinary warm reductions), vibrating arrhythmia (chaotic reductions of separate muscle fibers), blockade of the carrying-out system, etc.
Rhythmical consecutive reduction of departments of heart is provided with the special muscle fibers of a myocardium forming the carrying-out system of heart. In this system a driver of a rhythm of the first order is the sinusovy knot: in it excitement with a frequency of 60-80 times a minute arises. Through a myocardium of the right auricle it extends to atrioventricular knot, but it is less excitable and gives a delay therefore at first auricles and only then, in process of distribution of excitement on Gis's bunch and other departments of the carrying-out system, ventricles are reduced. Thus, the carrying-out system provides a certain rhythm, frequency and the sequence of reductions: at first auricles, and then ventricles. Defeat of the carrying-out system of a myocardium leads to development of violations of a rhythm (arrhythmias), and its separate links (atrioventricular knot, a bunch or Gis's legs) – to violation of conductivity (blockade). At the same time coordinate work of auricles and ventricles can sharply be broken.
Reasons of arrhythmias
For the reasons and the mechanism of developing of arrhythmia conditionally are divided into two categories: having communication with cardiac pathology (organic) and not related (inorganic or functional). Various forms of organic arrhythmias and blockade are frequent satellites of kardialny pathologies: IBS, myocarditis, cardiomyopathy, malformations and injuries of heart, heart failure, and also complications of cardiac operations.
Development of organic arrhythmias is the cornerstone of damage (ischemic, inflammatory, morphological) a cardiac muscle. They complicate normal distribution of an electric impulse through the carrying-out system of heart to its various departments. Sometimes damage affects also sinusovy knot – the main driver of a rhythm. When forming a cardiosclerosis cicatricial fabric interferes with implementation of the carrying-out function of a myocardium that promotes emergence of the aritmogenny centers and development of violations of conductivity and a rhythm.
The group of functional arrhythmias includes neurogenetic, diselektrolitny, yatrogenny, mechanical and idiopathic violations of a rhythm.
Development of simpatozavisimy arrhythmias of neurogenetic genesis is promoted by excessive activation of a tone of sympathetic nervous system under the influence of a stress, strong emotions, hard mental or physical activity, smoking, alcohol intake, strong tea and coffee, spicy food, neurosis etc. Activation of a sympathetic tone is also caused by diseases of a thyroid gland (thyrotoxicosis), intoxications, feverish states, blood diseases, virus and bacterial toxins, industrial and other intoxications, a hypoxia. The women suffering from a premenstrual syndrome can have simpatozavisimy arrhythmias, heartaches, feelings of suffocation.
Vagozavisimy neurogenetic arrhythmias are caused by activation of parasimpaticheky system, in particular, of the wandering nerve. Vagozavisimy violations of a rhythm usually develop at night and can be caused by diseases of a gall bladder, intestines, stomach ulcer of a 12-perstny gut and a stomach, bladder diseases at which activity of the wandering nerve increases.
Diselektrolitny arrhythmias develop at violations of electrolytic balance, especially magnesian, potassium, sodium and calcic in blood and a myocardium. Yatrogenny violations of a rhythm result from aritmogenny action of some drugs (warm glycosides, β-blockers, simpatomimetik, diuretics, etc.).
Development of mechanical arrhythmias is promoted by injuries of a thorax, falling, blows, damages by electric current etc. Violations of a rhythm without the established reason are considered as idiopathic arrhythmias. In development of arrhythmias hereditary predisposition plays a role.
Classification of arrhythmias
Etiologichesky, pathogenetic, symptomatic and predictive heterogeneity of arrhythmias causes discussions concerning their uniform classification. By the anatomic principle of arrhythmia are subdivided on predserdny, ventricular, sinusovy and atrioventricular. Taking into account frequency and rhythm of warm reductions it is offered to allocate three groups of violations of a rhythm: bradycardia, tachycardia and arrhythmia.
The fullest is the classification based on electrophysiological parameters of violation of a rhythm according to which allocate arrhythmias:
- I. The formations of an electric impulse caused by violation.
This group of arrhythmias includes nomotopny and geterotopny (ektopichesky) violations of a rhythm.
Nomotopny arrhythmias are caused by malfunction of automatism of sinusovy knot and include sinusovy tachycardia, bradycardia and arrhythmia.
Separately in this group allocate the syndrome of weakness of sinusovy knot (SWSK).
Geterotopny arrhythmias are characterized by formation of the passive and active ektopichesky complexes of excitement of a myocardium which are settling down out of sinusovy knot.
At passive geterotopny arrhythmias emergence of an ektopichesky impulse is caused by delay or violation of carrying out the main impulse. The violations of atrioventrikuoyarny connection, migration of the supraventrikulyarny driver of a rhythm which are jumping out reductions belong to passive ektopichesky complexes and rhythms predserdny, ventricular.
At active geterotopiya the arising ektopichesky impulse excites a myocardium before the impulse which is formed in the main driver of a rhythm, and ektopichesky reductions "kill" a sinusovy rhythm of heart. Active complexes and rhythms include: premature ventricular contraction (predserdny, ventricular, proceeding from atrioventricular connection), the paroksizmalny and neparoksizmalny tachycardia (proceeding from atrioventricular connection, predserdny and ventricular forms), trembling and blinking (fibrillation) of auricles and ventricles.
- II. The arrhythmias caused by malfunction of intracardial conductivity.
This group of arrhythmias results from decrease or the termination of distribution of an impulse on the carrying-out system. Violations of conductivity include: sinoatrialny, vnutripredserdny, atrioventricular (I, II and III degrees) blockade, syndromes of premature excitement of ventricles, intra ventricular blockade of legs of a bunch of Gis (one - two - and trekhpuchkovy).
- III. The combined arrhythmias.
To the arrhythmias combining violations of conductivity and a rhythm ektopichesky rhythms treat with blockade of an exit, a parasistoliya, atrioventricular dissociation.
Symptoms of arrhythmias
Displays of arrhythmias can be the most various and are defined by the frequency and a rhythm of warm reductions, their influence on intracardial, cerebral, kidney haemo dynamics, and also function of a myocardium of the left ventricle. Meet, the so-called, "mute" arrhythmias which are not proving clinically. They usually come to light at fizikalny survey or an electrocardiography.
As the main displays of arrhythmias serve heartbeat or feeling of interruptions, dying down during the work of heart. The course of arrhythmias can be followed by suffocation, stenocardia, dizziness, weakness, faints, development of cardiogenic shock. Feelings of heartbeat are usually connected with sinusovy tachycardia, attacks of dizziness and faints – with sinusovy bradycardia or a syndrome of weakness of sinusovy knot, dying down of warm activity and discomfort in heart – with sinusovy arrhythmia.
At premature ventricular contraction patients complain of feelings of dying down, a push and interruptions in work of heart. Paroksizmalny tachycardia is characterized by suddenly developing and stopping heartbeat attacks to 140-220 . in min. It is noted feelings of frequent, irregular heartbeat at vibrating arrhythmia.
Complications of arrhythmias
The course of any arrhythmia can be complicated by fibrillation and trembling of ventricles that is equivalent to a blood circulation stop and to lead of the patient to death. In the first seconds dizziness, weakness develop, then – consciousness loss, an involuntary urination and spasms. HELL and pulse are not defined, breath stops, pupils extend – there comes the condition of clinical death. Patients with chronic insufficiency have blood circulations (stenocardia, a mitralny stenosis), during paroxysms of a takhiaritmiya there is short wind and hypostasis of lungs can develop.
At total atrioventricular block or an asistoliya development of sinkopalny states (attacks of the Morganyi-Ademsa-Stoksa which are characterized by consciousness loss episodes) caused sharp decrease in warm emission and arterial pressure and reduction of blood supply of a brain is possible. Tromboembolichesky oslozheniye at vibrating arrhythmia in every sixth case lead to a brain stroke.
Diagnosis of arrhythmias
Primary stage of diagnosis of arrhythmia can be carried out by the therapist or the cardiologist. It includes the analysis of the complaints of the patient and definition of peripheral pulse characteristic of violations of a warm rhythm. At the following stage research methods are carried out tool noninvasive (the ECG, ECG monitoring), and invasive (ChpEFI, VEI):
The electrocardiogram writes down a warm rhythm and frequency for several minutes therefore by means of the ECG only constant, steady arrhythmias come to light. The violations of a rhythm having paroksizmalny (temporary) character are diagnosed by method of Holterovsky daily monitoring of the ECG which registers a daily rhythm of heart.
For identification of the organic causes of arrhythmia carry out Ekho-KG and a stress of Ekho-KG. Invasive methods of diagnostics allow to cause artificially development of arrhythmia and to define the mechanism of its emergence. During the intracardial electrophysiological research the electrodes catheters registering an endokardialny elektrogramma in various departments of heart are brought to heart. The Endokardialny ECG is compared to result of record of the external electrocardiogram which is carried out at the same time.
Tilt-test it is carried out on a special orthostatic table and imitates conditions which can cause arrhythmia. The patient is placed on a table in horizontal position, measure pulse and HELL and then after introduction of medicine incline a table at an angle 60-80 ° for 20 – 45 minutes, defining dependence HELL, frequencies and a rhythm of warm reductions from change of position of a body.
By means of a method of a chrespishchevodny electrophysiological research () carry out electric stimulation of heart through a gullet and register the chrespishchevodny electrocardiogram fixing a warm rhythm and conductivity.
A number of auxiliary diagnostic tests includes tests with loading (a step tests, test with squats, mid-flight, holodovy, etc. tests), pharmacological tests (with izoproterinoly, with a dipyridopier, with ATP, etc.) and are carried out for diagnostics of coronary insufficiency and a possibility of judgment of connection of load of heart with developing of arrhythmias.
Treatment of arrhythmias
The choice of therapy at arrhythmias is defined by the reasons, a type of violation of a rhythm and conductivity of heart, and also a condition of the patient. In certain cases for restoration of a normal sinusovy rhythm happens to carry out treatment of the main disease enough.
Sometimes treatment of arrhythmias requires special medicamentous or cardiac treatment. Selection and purpose of antiarhythmic therapy is carried out under systematic ECG control. On the mechanism of influence allocate 4 classes of antiarhythmic medicines:
- 1 class - the membrane stabilizing medicines blocking sodium channels:
- 1A – increase repolarization time (procaineamide, , , )
- 1B – reduce repolarization time (, lidocaine, )
- 1C - do not exert the expressed impact on repolarization (, , , , , a lappakonitina hydrobromide)
- 2 class – β-adrenoblokator (, propranolol, , , , )
- 3 class - extend repolarization and block potassium channels (, , , , a bretylium )
- 4 class - is blocked by calcic channels (diltiazy, verapamil).
Non-drug methods of treatment of arrhythmias include electrocardiostimulation, implantation of a kardiovertera-defibrillator, a radio-frequency ablation and surgery on open heart. They are carried out by heart surgeons in specialized offices. Implantation of an electropacemaker (EX-) – the artificial driver of a rhythm is directed to maintenance of a normal rhythm at patients with bradycardia and atrioventricular blockade. The implanted kardioverter-defibrillator in the preventive purposes is hemmed to patients at whom the risk of sudden emergence of a ventricular takhiaritmiya is high and automatically carries out cardiostimulation and a defibrillation right after its development.
By means of a radio-frequency ablation (heart RChA) through small punctures by means of a catheter carry out cauterization of the site of the heart generating ektopichesky impulses that allows to block impulses and to prevent development of arrhythmia. Surgeries on open heart are performed at the kardialny arrhythmias caused by aneurism of the left ventricle, defects of valves of heart etc.
The forecast at arrhythmias
In the predictive plan of arrhythmia are extremely ambiguous. Some of them (supraventricular premature ventricular contraction, rare ekstrasistola of ventricles), the hearts which are not tied with organic pathology, do not pose threat for health and life. Vibrating arrhythmia, on the contrary, can cause zhizneugrozhayushchy complications: ischemic stroke, heavy heart failure.
The heaviest arrhythmias are trembling and fibrillation of ventricles: they pose a direct threat for life and demand holding resuscitation actions.
Prevention of arrhythmias
The main direction of prevention of arrhythmias is treatment of kardialny pathology, practically always the becoming complicated violation of a rhythm and conductivity of heart. The exception of the ekstrakardialny reasons of arrhythmia is also necessary (a thyrotoxicosis, intoxications and feverish states, vegetative dysfunction, an electrolytic imbalance, stresses, etc.). Restriction of reception of excitants (caffeine), an exception of smoking and alcohol, independent selection of antiarhythmic and other medicines is recommended.