ENDOMYOCARDIAL BIOPSY IN RIGHT-VENTRICULAR CARDIOMYOPATHY

Right ventricular cardiomyopathy is characterized by a progressive myo cyte loss and fibro-fatty substitution of the right ventricle. The aim of our study was to assess the diagnostic accuracy of right ventricul ar endomyocardial biopsy. Using an imaging analyser system, histomorph ometric parameters of myocytes, interstitium, fibrous tissue and fatty tissue were evaluated on endomyocardial biopsy from 30 patients with arrhythmogenic right ventricular cardiomyopathy, 29 patients with dila ted cardiomyopathy and 30 control patients. The percent area of myocyt es decreased from 78.10 +/- 7.34 in control to 63.39 +/- 9.22 in dilat ed cardiomyopathy (P < 0.05) and to 47.28 +/- 15.01 in arrhythmogenic right ventricular cardiomyopathy (P < 0.01). Fibrous tissue increased from 8.10 +/- 3.89 in control to 21.80 +/- 9.29 in dilated cardiomyopa thy (P < 0.05) and to 24.60 +/- 11.37 in arrhythmogenic right ventricu lar cardiomyopathy (P < 0.05). Fatty tissue varied from 0.33 +/- 1.44 in control and 0.07 +/- 0.31 in dilated cardiomyopathy to 13.30 +/- 17 .30 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fat ty tissue was a feature of arrhythmogenic right ventricular cardiomyop athy (67% of patients vs. 6% of control and dilated cardiomyopathy pat ients). Diagnostic values typifying arrhythmogenic right ventricular c ardiomyopathy, obtained by excluding any overlapping between confidenc e intervals in the three groups, were: myocytes < 44.95%; fibrous tiss ue > 40.38%, and fatty tissue > 3.21%, with 67% sensitivity and 91.53% specificity for at least one parameter. In conclusion, a significant difference between arrhythmogenic right ventricular cardiomyopathy, di lated cardiomyopathy and control exists in terms of amount of myocytes , fibrous tissue and fatty tissue. Presence of fatty tissue and fibrou s tissue exceeding 3.21% and 40.38%, respectively should be considered highly suspect for arrhythmogenic fight ventricular cardiomyopathy in right ventricular endomyocardial biopsy.