CLINICAL AND HISTOPATHOLOGICAL STUDIES IN CHILDREN WITH SUPRAVENTRICULAR TACHYCARDIA

To determine whether myocardial changes in patients with supraventricu lar tachycardia (SVT) are primary or secondary to persistent tachycard ia, 11 patients with SVT were studied. These patients were divided int o 2 groups with respect to the type of SVT. Group I consisted of 5 pat ients with incessant SVT and one with multifocal atrial tachycardia, w hile group II consisted of 4 patients with paroxysmal supraventricular tachycardia and one with short-run supraventricular premature contrac tion. All of the patients underwent electrophysiological study and end omyocardial biopsy from the right ventricle following routine cardiac catheterization. In group II, there were no significant abnormalities in the clinical and hemodynamic parameters. In group I, 3 patients had clinical features of dilated cardiomyopathy including abnormal EGG, c hest X-ray and hypokinesis on left ventriculography. Induction and ter mination of SVT were possible in 2 patients in group I and in 4 of the 5 patients in group II. The only significant histologic difference be tween group I and group II was fibrosis. A high incidence of histopath ological abnormalities, such as hypertrophy, degeneration, interstitia l fibrosis and disarray was observed in both groups. The incidence of significant pathology was higher in group I than in group II. Almost a ll of the patients were given antiarrhythmic drugs. One patient underw ent a successful surgical procedure and normal cardiac function return ed after resection of the foci of the right atrium. Our present result s suggest that patients with SVT who have incessant or recurrent SVT s hould undergo not only intracardiac electrophysiologic study but also endomyocardial biopsy for the evaluation of myocardial damage, since S VT might be the initial sign of cardiomyopathy.