Clinical significance of late potentials in patients after intracardiac operation for congenital heart disease

Abstract

The aim of this study was to evaluate the late potentials (LPs) in postoperative patients with congenital heart disease (CHD) and to study the association with the clinical characteristics in the postoperative patients with LPs. Signal averaged electrocardiogram (SA-ECG) was recorded in 119 postoperative patients aged 4 to 23 years and compared with those in age matched 49 healthy volunteers with and without right bundle branch block. Based on control data, criterias of LP were defined and altered in the presence of bundle branch block. Abnormal SA-ECGs were not detected in the patients with non-cyanotic CHD. However, abnormal and borderline SA-ECGs were recognized in 5 (12%) of 42 patients after intracardiac operation for tetralogy of Fallot and 3 (30%) of 9 patients after Raste's operation. The patients with abnormal and borderline SA-ECGs were significantly older at the time of operation, and had more frequent ventricular arrhythmias (7/8: 3/111, p<0.01) and depression of the ST-T segment on ECG (7/8: 11/111, p<0.01), compared with the normal SA-ECG group. Abnormal SA-ECGs including those of borderline patients were 50% sensitive and 96% specific for documented ventricular arrhythmias. However, there was no association between anbnormalities of SA-ECGs and cardiomegaly on chest X-ray or left ventricular ejection fraction on echocardiogram. These results indicate that prolonged exposure to hypoxia may be the main cause of the primary role in the development of LPs. And late surgical intervention may result in histological background for the development of LPs. © 1992, The Japanese Circulation Society. All rights reserved.