OBJECTIVESTo study the pathologic features of arrhythmogenic right ventricular cardiomyopathy (ARVC) in the phase of heart failure.

METHODSEight cases underwent heart transplantation in Fuwai Hospital during the period from May, 2004 to July, 2007 with pathologic diagnosis of ARVC were studied. The age of patients ranged from 15 to 54 years. They had history of palpitation and syncope for 1 to 22 years. Severe heart failure was diagnosed according to the New York Heart Association Classification System. The recipient hearts were examined and the following parameters were evaluated: weight of heart, presence of cardiac dilatation, myocardial hypertrophy, fatty infiltration, fibrosis, parietal thrombosis and myocarditis. The degree of left ventricular involvement was also analyzed.

RESULTSOf the 8 cases studied, 7 cases with prominent right ventricular lesion (fibrofatty replacement) were classified as classic type. One case with prominent left ventricle lesion and mild right ventricle involvement was classified as left predominant type. No biventricular type and no pure fatty infiltration were found. The cases of classic type showed moderate to severe dilatation of right ventricle, sometimes with aneurysm formation. Left ventricle was involved in 6 cases, which showed diffuse interstitial fibrosis, patchy fibrous replacement and subepicardial fatty infiltration. Mild to moderate dilatation of left ventricle, myocardial hypertrophy and vacuolation were also observed in these cases. The case of left predominant type had severe hypertrophy and dilatation of left ventricle, with prominent diffuse interstitial fibrosis and transmural fatty infiltration. Besides, 3 cases showed left ventricular hypertrophy and parietal thrombosis in both ventricles. Focal lymphocytic myocarditis was noted in 1 case.

CONCLUSIONSLeft ventricular involvement is common in the heart failure phase of ARVC. Extensive interstitial fibrosis, marked hypertrophy and degeneration of myocardial fibers, as well as severe cardiac dilatation with organized thrombi, represent the major pathologic changes which resembles dilated cardiomyopathy.