Does right ventricular endomyocardial biopsy reveal distinct histopathological features in patients with ARVD compared to those with dilated cardiomyopathy or chronic right ventricular overloading?
Right ventricular endomyocardial biopsy demonstrates that increased fatty tissue and interstitial fibrosis are prominent histopathological features in patients with ARVD-related ventricular arrhythmias.
Right ventricular endomyocardial biopsies were performed in patients with repetitive ventricular tachycardia (VT; 8 patients) or ventricular premature beats (1 patient) which showed left bundle branch block morphology in electrocardiograms. These 9 male patients ranging in age from 21-55 years (mean 37.7 years) revealed enlargement and/or asynergy of the right ventricle in the ventriculogram. Randomly selected biopsied patients with dilated cardiomyopathy (DCM; 18 patients) and chronic right ventricular overloading (14 patients) who did not show the above-described arrhythmias served as controls. A histopathological analysis revealed advanced myocardial interstitial fibrosis associated with an increase in fatty tissue in 8 of the 9 patients (89%). Moreover, advanced hypertrophy of myocytes (grade 2 or more of our criteria), disarrangement of muscle bundles and endocardial thickening were prominent with incidences of 75%, 75% and 78%, respectively. Incidence of all findings was more pronounced in the ARVD group. Suggestiveness of post-myocarditic change in the biopsied specimen was high in 1 patient, showing a lower incidence (12%) than the DCM group (17%). From these results, we can conclude that different etiological factors may be the bases of these pathological changes. We believe that the presence of a large amount of fatty tissue within the myocardial tissue is an important element in the etiology of ventricular arrhythmias as it has also been recognized in patients with non-ARVD idiopathic ventricular tachycardia in our biopsy series.
Hasumi et al. (Thu,) studied this question.