Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy: A Review

Right ventricular dysplasia is being recognized with increasing frequency. It should be considered as a cause of ventricular tachycardia of left bundle branch block configuration and/or sudden unexpected death particularly during exercise in young men. The electrocardiogram (ECG) may show anterior precordial T wave inversion, particularly in lead V2 and/or a QRS complex duration > or = 110 ms in the right precordial leads. Echocardiographic studies focusing on the size and wall-motion abnormalities of the right ventricle are useful in confirming the diagnosis. Radionuclide angiography usually shows a moderately or markedly depressed right ventricular ejection fraction with normal or relatively well preserved left ventricular function. Cinemagnetic resonance imaging demonstrates abnormal fatty infiltration of the right ventricular myocardium and can show increased right ventricular dimensions as well as wall-motion abnormalities. Contrast ventricular angiography remains the gold standard to establish the diagnosis but must be performed with appropriate views and with care to avoid ventricular premature beats. Quantitative analysis of right ventricular dimensions can be performed in selected centers. Three-dimensional echocardiography is a promising approach to evaluate right ventricular wall-motion abnormalities as well as to demonstrate enlargement. The etiology and pathogenesis of this condition is not clear. A familial incidence has been well-documented in certain areas and an abnormal gene has been identified. Sporadic cases are the most common. In contrast to Uhl's anomaly, characterized pathologically by areas of paper thin myocardium, the right ventricular free wall is minimally decreased in thickness. Histologically there appears to be a replacement of musculature by fatty tissue. Medical therapy with sotalol or amiodarone, or combination therapy (Class Ic drugs plus beta-blocking drugs, or amiodarone plus beta-blocking drugs) is frequently effective in preventing recurrent ventricular tachycardia. Ablation using radiofrequency (RF) or direct current (DC) energy is reserved for patients who are unresponsive or intolerant of antiarrhythmic drugs. Ventricular arrhythmia recurrence of different morphology is not uncommon after apparent successful ablation. There appears to be a lower rate of successful ablation using RF energy. However, patients with this condition who have been resuscitated from sudden cardiac death or those refractory to medical treatment are candidates for ablation, implantation of an automatic cardioverter defibrillator, or cardiac transplantation. Surgery consisting of total disconnection of the right ventricle is a promising therapeutic modality.