[Diastolic micropotentials in high-resolution surface ECG in QT syndrome]

Patients suffering from long QT syndrome are threatened by torsade de pointes tachycardias and sudden arrhythmic cardiac death. An inhomogenic sympathetic innervation of the heart with dominance of the left cervicothoracic sympathetic nerves has been considered to be a major cause of life threatening cardiac arrhythmias. This study presents the electrocardiographic and electrophysiologic results of 7 patients with long QT syndrome. In agreement with data published earlier our results of Holter monitoring, exercise testing and programmed electrical right ventricular stimulation were of no diagnostic or prognostic significance in predicting syncopal attacks or sudden arrhythmic cardiac death. Thus, the high resolution ECG methods played an important role in this study. During noninvasive recordings of signal averaged ECGs and high resolution surface ECGs with beat to beat registration, diastolic microvolt potentials could be detected in 6/7 patients within the ST segment and in 5/7 patients after the T wave. Our results evidently show that the signal averaged ECG and the high resolution surface ECG could be of diagnostic significance in patients with long QT syndrome.