The arrhythmogenic right ventricle. Dysplasia versus cardiomyopathy

Abstract

Twenty-four patients presenting with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ventricular tachycardia of right ventricular origin associated with structural abnormalities of the right ventricle) were divided into two groups with left ventricular ejection fraction (LVEF) above or below 45%. The distribution of LVEF in the group with LVEF below 45% was comparable with the distribution in 6 patients with idiopathic dilated cardiomyopathy who had ventricular tachycardia originating in the left ventricle (P = 0.2). They also had the same unfavorable long-term prognosis. Therefore, it is suggested that the term, arrhythmogenic right ventricular cardiomyopathy (ARVC), be restricted to patients with a LVEF below 45%. Histological data obtained in the ARVC group showed signs of acute or chronic myocarditis (in the right and left ventricles). It can be hypothesized that patients with arrhythmogenic right ventricular dysplasia (ARVD) may be prone to develop infectious myocarditis. In patients in whom an abnormal host immune response had been seen, progressive deterioration of right and left ventricular function could be observed. This pattern may be superimposed on the genetically determined background of ARVD. This could explain the wide spectrum of clinical presentation observed in patients with tachycardia originating in an abnormal right ventricle.

Arrhythmogenic Right Ventricular Cardiomyopathy and Fatty Replacement of the Right Ventricular Myocardium

“…The large percentage of cases of fibrofatty ARVC in the present study supports the concept that in many cases, fibrofatty ARVC is an end stage of a remote inflammatory process, with increased cell death possibly due to apoptosis. 15 However, this study does not rule out the possibility that inflammation is a superimposed process, as favored by Fontaine et al 16 It remains to be proven whether fibrofatty ARVC is ever the result of a previous viral infection, as molecular studies for enteroviral RNA suggest in a small proportion of cases of idiopathic dilated cardiomyopathy. 17 The present study demonstrates that with extensive sampling of the left ventricular myocardium, fibrofatty replacement of the epicardium may be found in a majority of cases of fibrofatty ARVC.…”

Implantable Cardioverter-Defibrillator Therapy for Prevention of Sudden Death in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia

“…2,[3][4][5]18,19 This view is reinforced by the present finding that younger age is an independent risk factor for ventricular fibrillation/flutter. Fontaine et al 20 reported a bimodal distribution of left ventricular ejection fraction in ARVC/D patients, with mean values of 58% and 25%, respectively, and advanced the hypothesis that this pattern was accounted for by a superimposed factor, such as acute myocarditis leading to hemodynamic deterioration of the left ventricle. The subgroup of patients with severe left ventricular dysfunction showed an increased mortality rate due to congestive heart failure.…”

Plakophilin-2 Mutations Are the Major Determinant of Familial Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

“…On the other hand, the absence of PKP2 mutations in nonfamilial ARVC cases suggests the possibility of a nongenetic origin, eg, myocarditis or alternatively a spontaneous mutation in another gene. 38,39 Finally, all 5 index patients with familial ARVC and sudden death in family members Ͻ35 years of age appeared to be PKP2 mutation carriers.…”