Relation between myocardial histological changes and ventricular tachycardia in cardiomyopathy: a study by 24-hour ECG-monitoring and endomyocardial biopsy.

The relation between myocardial histological changes and ventricular tachycardia (VT) in cardiomyopathy was investigated. Right ventricular endomyocardial biopsy and 24-hour ECG-monitoring were performed in 19 patients with dilated cardiomyopathy (DCM) and 22 with hypertropic cardiomyopathy (HCM). Cardiomyopathy was histologically divided into the following four groups: group A, hypertrophy without disarray of myocytes (3 DCM and 7 HCM); group B, hypertrophy with disarray of myocytes (14 HCM); group C, fibrosis (9 DCM and 1 HCM); and group D, diffuse myocytic degeneration (7 DCM). VT was observed in 20% (2 of 10 patients) of group A, 14% (2 of 14) of group B, 80% (8 of 10) of group C, and 71% (5 of 7) of group D. The degenerating myocytes and/or the irregular distribution of fibrosis may play an important role in the etiology of VT in cardiomyopathy.