Arrhythmogenic Dysplasia of the Right Ventricle . Ventricular arrhythmias originating in the right ventricle usually affect young patients and can lead to sudden cardiac death.
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- 1 Definition
- 2 Prevalence
- 3 Genetic aspects
- 4 Structural abnormalities
- 5 Clinical presentation
- 6 Diagnosis
- 7 Differential diagnosis
- 8 Stratification of risk
- 9 Sources
- 10 External links
It is a disease characterized by the partial or massive progressive replacement of the myocardium by adipose or fibro-fatty tissue which constitutes the pathophysiological substrate of ventricular arrhythmias (VA) ranging from isolated ventricular extrasystoles (EV) to ventricular tachycardias (TV) sustained or ventricular fibrillation (VF) and sudden cardiac death (MSC).
The prevalence of the disease in the general population has been estimated at values ranging from 1 / 2,000 to 1 / 10,000. 80% of cases are diagnosed in patients younger than 40 years. This should be suspected in all young patients with an apparently normal heart suffering from syncope, ventricular tachycardia, or cardiac arrest.
Arrhythmogenic dysplasia of the right ventricle is an inheritable disorder. There is a clear family incidence (30-50% of cases) with an autosomal dominant transmission pattern, varying degrees of penetration, and polymorphic phenotypic expression.
DAVD is characterized by a replacement of the myocardiumby adipose and fibrous tissue that initially affects the epicardium and later the endocardium. This process affects most of the time the posterior and inferior areas of the right ventricular (RV) entrance tract adjacent to the tricuspid valve, but it also affects the anterior infundibulum and the cardiac vertex, forming what is called the dysplasia ”. Loss of myocardium can cause focal thinning of the free ventricular wall, with focal bulging of the right ventricular wall in diastole and enlargement of the right ventricular outflow tract. From a functional point of view, the disease can cause general or regional contraction abnormalities, disturbances of systolic / diastolic function of the right ventricle, RV aneurysm formation and RV dilatation and hypokinesia.
DAVD usually manifests in the form of TV episodes, with left bundle branch block morphology (BRIHH) and origin in the RV in apparently healthy adolescents or young adults. AVs can be asymptomatic and detected on a systematic ECG or can cause palpitations, syncope, or MSC. The DAVD has been estimated to explain up to 5-20% of SCD cases in individuals under 35 years of age.
However, the clinical manifestations of the disease can vary widely in terms of onset and severity.
The interaction between different genetic substrates with different degrees of penetration and the presence of external triggers (such as strenuous exercise or vigorous training) explain this wide spectrum of forms of clinical presentation, including palpitations, fatigue, atypical chest pain, syncope and MSC. . The age at which the first manifestation occurs ranges from 15 to 35 years. The disorder affects men more frequently than women, and it usually manifests itself in them with a broader expression of the disease.
The heart failure symptom is a common manifestation of ARVD little and most often occurs in advanced stages of the disease. Patients with a long history of DAVD have affected the left ventricle and suffer clinical symptoms of biventricular heart failure.
The diagnosis of DAVD is based on the presence of structural, histological, electrocardiographic, arrhythmic, genetic factors and on a family history.
The main differential diagnosis of DAVD is to be made with RV Ventricular Tachycardia (SVD-TV), sarcoidosis, idiopathic dilated cardiomyopathy, and isolated myocarditis. Both DVT-TSVD and DAVD occur in apparently healthy young individuals, and both can be manifested by EV or VT with Hiss Left Bundle Branch Block (BRIHH) and a lower axis.
Existing data indicates that RV dysfunction is severe: involvement of the left ventricle, syncope, early age of onset, male gender, history of cardiac arrest, rapid and poorly tolerated VT with different morphologies, and family incidence of sudden juvenile deaths are the main factors that determine a bad evolution. High-risk patients have clinical signs of right heart failure and / or have left ventricular dysfunction, as well as a history of VT.
These patients should be considered candidates for vigorous therapeutic management. In contrast, patients without VT have a very low risk of cardiac episodes. There is still debate about whether or not the electrophysiological study can be useful to predict the appearance of a VT during follow-up. Lifestyle recommendations, that is, limiting vigorous physical activity, can improve long-term outcomes.