NOCTURNAL VENTRICULAR ECTOPY IN PATIENTS WITH SLEEP-APNEA AND SUSPECTED CORONARY HEART-DISEASE

Background: Patients with sleep apnea and nocturnal brady- and tachyar rhythmia are considered to be patients at especially high risk within the group of all apnea patients. Patients and methods: 13 patients wit h sleep apnea (apnea-index > 10 events/h), suspected coronary heart di sease and known increased frequency of nocturnal premature ventricular contractions (PVC) were studied. Polysomnography, long-term ECG and s ix-lead ECG were performed. Results: Within the period studied (1.00 t o 6.00 o'clock), an average of 47 PVC per hour was recorded (range 4 t o 337/h). In two patients 24 episodes of nocturnal myocardial ischemia were observed, but were not accompanied by PVC. Interestingly only 38 7 of 1371 premature ventricular contractions (28.2%) were associated t o apnea/hyperventilation episodes. Arrhythmia occurred mainly during s leep stages I/II and REM (n. s.). There was a tendency towards more fr equent PVC with more pronounced oxygen desaturations. Conclusion: Pati ents with coronary heart disease, obstructive sleep apnea and severe h yoxemia are at higher risk of developing nocturnal PVC because reduced hypoxic tolerance of the heart may lead to electrical instability.