[Clinical investigation on the patients with tachyarrhythmic syncope with special reference to comparative study between long QT syndrome and ventricular tachycardia without long QT interval].

The long QT syndrome (LQTS) is one of the important diseases that may lead to sudden death mainly in childhood, however etiology and pathogenesis are still poorly understood. The group studied consisted of 6 patients with a history of ventricular tachyarrhythmic syncope, 3 with long QT syndrome (LQTS) and 3 without long QT interval, and of 4 patients with ventricular tachycardia without syncopal episode. Their ages ranged from 5 years to 17 years. Histopathology of endomyocardial biopsy was nonspecific and mild in two cases but in one patient with LQTS, who had several episodes of syncope and refractory ventricular arrhythmia, remarkable subendocardial fibrosis, interstitial fibrosis and hypertrophy of myocytes were demonstrated. As far as ventricular tachycardia without long QT interval was concerned, in the patients with VT with syncope, histopathological abnormalities were more remarkable than in those without syncope. Electrophysiological findings in the patients with LQTS showed no characteristic findings, but only mild abnormalities with functional atrioventricular conduction disturbance on programmed atrial pacing. No inducible VT was demonstrated. Although electrophysiologic study and endomyocardial biopsy are of limited value, such studies are considered to be worthwhile for treating ventricular arrhythmias, and making a prognosis of the patients with tachyarrhythmic syncope and LQTS.

[Clinical investigation on childhood HCM; long-term follow-up study with special reference to electrophysiology, histopathology by endomyocardial biopsy and ambulatory and exercise electrocardiography].

In order to determine the prognosis and risk factors of childhood HCM, we investigated clinical parameters, such as the age of onset, symptoms and signs related to HCM, dysrhythmias and ST-T and changes by Holter ECG and exercise ECG, electrophysiological study and histopathological study by endomyocardial biopsy. Heart murmur was the commonest sign although only one patient revealed a significant left ventricular outflow tract gradient of more than 20 mmHg. The peak age of patients diagnosed as having HCM was 10 to 15 years. The major ECG manifestations of our series showed specific findings and in some cases ECG changed remarkably during the follow-up period. The diagnosis of apical hypertrophy should be made with caution in childhood. Holter ECG seemed to be indispensable for the follow-up of childhood HCM because Holter ECG in our patients manifested such significant findings as ventricular premature contractions or couplets or ST depression. The degree of clinical severity did not always correlate with the histopathological severity obtained by endomyocardial biopsy. As HCM in childhood is heterogeneous and multifaceted, there is no one therapy, and prognosis and proper treatment with close observation should be carried out in each individual case.

Endomyocardial biopsy in children with Kawasaki disease.

To study the histopathology of the myocardium in Kawasaki Disease (KD) with various coronary angiographic findings, right endomyocardial biopsy specimens were evaluated on 20 boys and 16 girls with this disorder. KD with coronary artery lesions (CAL) showed various histopathological abnormalities, such as myocellular hypertrophy in 44%, degeneration in 61%, interstitial fibrosis in 44% and endomyocardial changes in 22%. KD without CAL revealed myocellular hypertrophy in 44%, degeneration in 50%, disarray in 28% and interstitial fibrosis in 6%. As in patients with long-standing KD, more than three years after onset, myocardial changes such as myocellular hypertrophy, disarray and interstitial fibrosis persisted, it is suggested that cardiomyopathy may develop in some patients with KD.