Clinical significance of ventricular late potentials in patients with obstructive sleep apnoea

Patients with obstructive sleep apnoea (OSA) have an increased cardiovascular mortality and probably also an increased incidence of sudden cardiac death. Thus the question arises whether ventricular late potentials can constitute markers for an increased electric vulnerability in these patients. Signal-averaged electrocardiograms were recorded in 64 patients (6 female, 58 male; mean age 53.2 y) with OSA (mean apnoea-hypopnoea index (AHI) 41.7 h-1 +/- 24.3 h-1). Furthermore, a continuous ambulatory electrocardiogram and gated radionuclide ventriculography were performed. Ventricular late potentials were recorded in 5 men out of 64 patients. Two of them had coronary artery disease (1 patient post-myocardial infarction), 2 hypertension, and 1 nocturnal hypertension. No correlation could be traced between left ventricular ejection fraction, severity and extent of ventricular premature beats, or severity of OSA and occurrence of ventricular late potentials. It was noticeable, however, that the patients with ventricular late potentials had severe OSA (mean AHI 50.2/h vs. 40.9/h). Although OSA may lead to structural myocardial changes that could be the basis for re-entrant circuits, ventricular late potentials were found in only 7.8% of these patients. The results of this study demonstrate that at present ventricular late potentials and signal-averaged electrocardiograms do not prove useful as screening methods for risk stratification of patients with OSA.