Aritmogenny right ventricular cardiomyopathy
Aritmogenny right ventricular cardiomyopathy – the disease of presumably genetic nature which is characterized by structural changes of the right ventricle and development of arrhythmia. Options of a current vary from asymptomatic forms to forms with the expressed takhiaritmiya, premature ventricular contraction, a kardialgiya and heart failure. Diagnostics is performed by means of echocardiographic, electrocardiographic, magnetic and resonant researches, and also a myocardium biopsy. Specific treatment is absent, therapy comes down to elimination of arrhythmia and stagnant heart failure. In the absence of effect of medicamentous therapy apply implantation of a kardioverter-defibrillator.
Aritmogenny right ventricular cardiomyopathy
Aritmogenny right ventricular cardiomyopathy (aritmogenny dysplasia of the right ventricle, aritmogenny disease of the right ventricle, AP KMP) – the disease affecting a wall of the right ventricle at which in the thickness of a myocardium the pathological centers of fatty and fibrinozny infiltration, sometimes with accession of an inflammation (myocarditis) are formed. Pathology was described under the name "aritmogenny dysplasia of the right ventricle" in 1977 G. Fontaine, after this research continued F. I. Marcus which in 1982 gave a disease the modern name.
Occurrence in various regions fluctuates within 1-6:10000 inhabitants; among the found patients the vast majority is made by men 40 years, sexual distribution - 4:1 are younger. Tends to hereditary transfer therefore now the majority of the AP KMP forms define as an autosomno-prepotent disease with an incomplete penetrantnost. Interest in a disease sharply increased in connection with identification of its role in development of sudden warm death. So, histologic researches of a myocardium at children and teenagers up to 20 years which cause of death cardiovascular pathology was showed that the changes associated with AP KMP were found in 26% of cases.
Reasons of an aritmogenny right ventricular cardiomyopathy
At the moment there is no conventional point of view on the reasons of development of AP KMP in view of heterogeneity of displays of a disease. Perhaps, AP KMP unites in itself several pathologies, similar in manifestations, with various etiology. But the only documentary confirmed theory is hereditary, explaining emergence of an aritmogenny right ventricular cardiomyopathy with a genetic mutation today.
When studying a genome of sick AP KMP anomalies of genes in the 12th, 14th, 17th and 18th chromosomes were revealed – the specified genes code such proteins of a myocardium as alpha , , , and others. Violations of structure of these proteins lead to decrease in resistance of kardiomiotsit to the damaging factors, as leads to fatty infiltration over time. However the major role in development of arrhythmia at AP KMP is played by violation of functions of protein of desmosomes therefore distribution of excitement on a myocardium changes.
In certain cases instead of focal fatty infiltration of walls of the right ventricle it is observed fibrinozny, having inflammatory character and in general reminding a picture at the viral myocarditis caused by Koksaki's virus, etc. Such form tends to distribution on the left ventricle and is characterized by the heavy current which is often leading to the death of the patient. From the point of view of the hereditary theory of development of AP KMP, it is considered that mutations of genes increase predisposition of a myocardium to defeat by viruses.
The majority of mutations are inherited on autosomno-prepotent type with a penetrantnost of 30-50%. One extremely rare form of an aritmogenny right ventricular cardiomyopathy (a disease of Naxos - only 25 cases are described) has autosomno-recessive character and a high penetrantnost – more than 90%. Gomozigota on a mutant gene suffer from malignant ventricular arrhythmia and often die in the childhood or teenage age.
Classification of an aritmogenny right ventricular cardiomyopathy
In view of the expressed heterogeneity of the AP KMP clinical forms attempts to systematize and classify types of this disease repeatedly were accepted. Now allocate the following types of an aritmogenny right ventricular cardiomyopathy:
- Pure, or reference, form.
- The disease of Naxos characterizing by autosomno-recessive inheritance and malignant ventricular arrhythmias.
- The Venetian cardiomyopathy – quite often extends to a wall of the left ventricle, has the expressed hereditary character (a penetrantnost about 50%), patients can die at children's age.
- Smoke a disease – the AP KMP form revealed in Japan serves as the reason of sudden warm death of teenagers.
- The tachycardia caused by the excitement center in the right ventricle without or displays of heart failure.
- Rare ventricular ekstrasistola, which source – the excitement center in a wall of the right ventricle associated with the site of an inflammation. Such AP KMP form can be complicated by myocarditis with a lethal outcome.
- Ul's anomaly – the AP KMP rare form characterizing by increase of heart failure and death. At a histologic research of heart full replacement of kardiomiotsit with fatty and fibrinozny tissue is found.
- The Nearitmogenny form – in most cases proves nothing, associate asymptomatic cases of sudden warm death with it.
Symptoms of an aritmogenny right ventricular cardiomyopathy
The AP KMP clinical forms are divided into four main groups. At an asymptomatic form pathology does not prove in any way during lifetime of the patient including at electrocardiographic researches. The arhythmic form is characterized by development of a takhiaritmiya, ventricular premature ventricular contraction and emergence of other electrocardiographic signs. Subjective symptoms, as a rule, are absent. At development of the expressed clinical form against the background of takhiaritmiya there are kardialgiya, attacks of heartbeat, dizziness. The heaviest type of clinical manifestations of AP KMP is development of heart failure in right ventricular type with characteristic simptomokompleks – venous stagnation, hypostases, ascites. At the same time heart failure can proceed both against the background of violation of a rhythm of heart, and without it.
In certain cases these groups reflect staging of development of the violations caused by an aritmogenny right ventricular cardiomyopathy. However at one patients development of pathology can last for years whereas at others from an asymptomatic form to heart failure there can pass less than a month. Besides, at any of forms or any stage AP KMP the lethal outcome because of fibrillation of ventricles, Ul's anomaly or lightning viral myocarditis is possible.
Diagnostics of an aritmogenny right ventricular cardiomyopathy
For diagnostics of AP KMP in cardiology all range of modern techniques of a research of function of heart is used. The final diastolic size (FDS) and the final systolic size (FSS) of ventricles then these data are compared among themselves is defined on EhoKG. If the relation of KDR of the right ventricle to KDR of left makes 0,5 and more, it testifies in favor of existence of AP KMP. Lengthening of a ventricular complex over 110 ms on assignment of V1, an epsilon wave on ST segment in assignments of V1-V3, inversion of a tooth of T in chest assignments because of delay of depolarization of the right ventricle, and also existence of a takhiaritmiya and ventricular belong to ECGs signs of an aritmogenny right ventricular cardiomyopathy.
On a X-ray contrast ventrikulografiya it is possible to define a dilyatation of the right ventricle, and in some cases protrusion (aneurism) in the field of the center of a fibrolipozny dysplasia of a myocardium is directly visualized. In recent years the magnetic and resonant tomography with gadolinium contrasting allowing not only to receive the three-dimensional image of heart, but also to differentiate the fatty and fibrinozny centers from not changed myocardium is applied to specific diagnostics of AP KMP. For specification of the diagnosis practice a myocardium biopsy with the subsequent histologic studying of fabrics – at AP KMP fatty infiltration, change of color and a form of desmosomes, and also reduction of their quantity will be observed.
Important sign is family character of symptoms or presence at the patient of the relatives who died from sudden warm death or fibrillation of ventricles. Differential diagnostics is made with idiopathic forms of ventricular takhiaritmiya.
Treatment of an aritmogenny right ventricular cardiomyopathy
Drug treatment of AP KMP includes antiarrhytmic medicines (, ). Decrease in expressiveness of takhiaritmiya plays an important role in preservation of life of the patient, the cardiologist makes control of efficiency of medicines by means of holterovsky monitoring. When medicamentous therapy is ineffective, resort to implantation of a kardioverter-defibrillator or pacemaker. At development of heart failure use APF inhibitors, .
Are developed technology of surgical treatment of an aritmogenny right ventricular cardiomyopathy (ventrikulotomiya) which come down to removal of the pathological centers with a myocardium ushivaniye. The first results of such operations are optimistical, however a recurrence arises in 30-40% of cases. At the expressed heart failure transplantation of heart will be an effective method of treatment.
Forecast and prevention of AP KMP
The forecast uncertain because of high variability of manifestations of AP KMP. Fibrillation of ventricles with a lethal outcome can develop at any time, especially in the absence of treatment. At regular antiarrhytmic therapy the risk of a lethal outcome decreases approximately on a third. The best results are shown by a combination of pacemakers and medicamentous therapy which reduces risk of emergence of lethal fibrillation practically to zero. At development of heart failure the forecast, as a rule, adverse.