Right ventricular arrhythmogenic dysplasia

In Russia, arrhythmogenic dysplasia of the right ventricle was first described by G.I. Storozhakov and co-authors.

Arrhythmogenic right ventricular cardiomyopathy (APHC), or arrhythmogenic dysplasia of the right ventricle, is a disease in which a normal right ventricular myocardium is replaced by a fatty or fibrous-fat tissue. Usually there is an isolated lesion of the right ventricle, but the interventricular septum and myocardium of the left ventricle may be involved in the process.

ICD-10 code

142.8. Other cardiomyopathies.

Epidemiology

The incidence in the population depends on the region and varies from 6 to 44 cases per 10 000 population. The most common arrhythmogenic dysplasia of the right ventricle occurs in the Mediterranean regions. In 80% of cases it is found at the age of up to 40 years, a cup for men.

Right ventricular arrhythmogenic dysplasia is the cause of 5-20% of sudden death at a young age (second place after HCMC).

[1], [2], [3], [4], [5], [6], [7]

The causes of arrhythmogenic right ventricular dysplasia

The cause of the disease remains unclear until now. There are data on the hereditary nature of APHC. Genetic disorders of several chromosomes in family cases of arrhythmogenic right ventricular dysplasia have been established.

It is suggested that changes in chromosomes lead to the pathology of proteins forming intercellular connections. Violations of these compounds lead to the death of cardiomyocytes and their fibro-fat substitution. Genetic disturbances in arrhythmogenic right ventricular dysplasia (ESC, 2008) are associated with a family gene, a mutation of the insertion disk protein (plakoglobin, desmoplakin, plakofilin 2, desmoglein 2, desmocollin 2). There is also an inflammatory theory of arrhythmogenic right ventricular dysplasia in the outcome of viral myocarditis in genetically predisposed individuals with altered myocardium.

Macroscopically in patients with APHC observed local or generalized dilatation of the right ventricle with thinning of the myocardium. Typical localization of changes - the tip, infundibular and subtracuspid region ("triangle of dysplasia").

A microscopic criterion of diagnosis is the presence of foci of fibrous-adipose tissue, alternating with an unchanged myocardium.

Symptoms of arrhythmogenic right ventricular dysplasia

Symptoms of arrhythmogenic right ventricular dysplasia vary from asymptomatic forms to cases of sudden death or severe biventricular heart failure.

Right ventricular arrhythmogenic dysplasia usually debuts with ventricular arrhythmia: extrasystoles of various gradations, short "jogging" of the ventricular tachycardia, and in some cases - paroxysms of stable ventricular tachycardia. Since the arrhythmogenic focus is in the right ventricle, the ectopic ventricular complexes have the appearance of blocking the left leg of the bundle of His.

There may be atypical pain in the chest, weakness, increased fatigue, episodes of palpitations during exercise. Arrhythmogenic collapse occurs during exercise or spontaneously.

In case of physical examination, in half the cases no deviations are found.

In the late stages of patients, circulatory insufficiency may develop, which causes serious difficulties in the differential diagnosis of APHC with dilated cardiomyopathy.

Diagnosis of arrhythmogenic right ventricular dysplasia

A number of international cardiological societies adopted WJ McKenna's diagnostic criteria for arrhythmogenic right ventricular dysplasia. Highlights small and small criteria. The presence of arrhythmogenic right ventricular dysplasia is indicated by the establishment of 2 large criteria, 1 large and 2 small criteria or 4 small criteria from different groups.

Criteria for diagnosis of arrhythmogenic right ventricular dysplasia (McKenna WJ et al., 1991)

Criteria	Great signs	Small signs
Global and / or regional dysfunction and structural changes	Significant dilatation and reduction of right ventricular ejection fraction in the absence of changes (or a slight change) in the left ventricle Local right ventricular aneurysms Significant segmental dilatation of the right ventricle	Moderate dilatation of the right ventricle and / or a decrease in its ejection fraction with a normal left ventricle Moderate segmental dilatation of the right ventricle Regional hypokinesia of the right ventricle
Characteristics of the web tissue	Fibrous-fatty degeneration of the myocardium with endomyocardial biopsy	-
Repolarization anomalies	-	Inversion of the T-wave in the right V2 and V3 of the thoracic leads in patients over 12 years old in the absence of blockade of the right leg of the ray of the Guiss
Anomalies of depolarization / conduction on ECG	Epsilon waves or local increase in the duration of the QRS complex (> 110 ms) in the right breast leads (V1-V3)	Late potentials of the ventricles on the high-resolution ECG
Arrhythmias	-	Steady or unstable ventricular tachycardia (with complexes such as left bundle branch block) according to ECG, daily monogorization and sample with exercise. Frequent ventricular extrasystole (> 1000 / day)
Family history	Family character of the disease, confirmed by autopsy data or during surgery	Sudden death of relatives younger than 35 with the expected arrhythmogenic right ventricular dysplasia Family history data (clinical diagnosis based on these criteria)

To clarify the nature of rhythm disturbances and assess the risk of fatal arrhythmias, an electrophysiological study is performed.

For the diagnosis of arrhythmogenic right ventricular dysplasia, visualization methods are of great importance.

With echocardiography (including contrast), anomalies of contractility of the right ventricle are established.

Magnetic resonance imaging helps detect an increased fat content in the myocardium.

The "gold standard" for diagnosis of arrhythmogenic right ventricular dysplasia is ventriculography.

Reliable diagnostic signs of right ventricular arrhythmogenic dysplasia can be determined with endomyocardial biopsy, which is performed in the area of the interventricular septum and the free wall of the right ventricle. The sensitivity of the method is about 20%, since it is not always possible to take a biopsy from the affected area.

[8], [9], [10], [11], [12], [13],

Treatment of arrhythmogenic right ventricular dysplasia

The disease has a steadily progressing nature, but with timely diagnosis and adequate treatment, the prognosis can be significantly improved.

The impact of APHC is aimed at preventing sudden death and treating heart failure.

Treatment of CHF in AFZHK assumes the standard use of diuretics, ACE inhibitors, digoxin and, in the presence of indications, anticoagulants.

Among antiarrhythmics, the greatest experience has been accumulated with respect to amiodarone and sotalol. The latter is most effective, therefore, in order to treat ventricular arrhythmias and prevent sudden death, treatment with sotalol is recommended. If it is ineffective, non-drug methods should be used, in particular implantation of a cardioverter-defibrillator.

Carrying out radiofrequency ablation has a low efficiency, as recurrences of arrhythmias develop, caused by activation of new foci.

The only way to treat arrhythmogenic right ventricular dysplasia in patients refractory to conservative effects is heart transplantation.