Histopathologic aspects of endomyocardial biopsy in pediatric patients with idiopathic ventricular tachycardia

Purpose: The present study aimed to investigate the clinicopathologic findings and histopathologic characteristics of endomyocardial biopsy in pediatric patients with idiopathic ventricular tachycardia. Methods: Histopathological findings of endomyocardial biopsy from 17 patients aged 7-15 years with idiopathic ventricular tachycardia (VT) but no organic heart disease were examined. Patients considered to have cardiomyopathy of the dilated, hypertrophic or specific form or arrhythmogenic right ventricular cardiomyopathy were excluded from this study. Results: Advanced histopathologic findings, including myocyte hypertrophy, degeneration, interstitial fibrosis and disarrangement of muscle bundles, were disclosed in three cases (17.6%). One of these cases exhibited sustained VT with left bundle branch block configuration and showed increased frequency of VT during exercise testing. The remaining two cases had non-sustained VT with multifocal origin and had syncope episodes. Another 14 cases showed mild or no significant findings in the biopsy. Conclusions: These results indicate that advanced histopathology in endomyocardial biopsy is occasionally disclosed in cases of idiopathic VT, especially those of exercise-related VT or multifocal VT, and that these patients may be considered as having heart muscle disease.