[Nocturnal ventricular arrhythmia in patients with sleep apnea and suspected coronary heart disease].

BACKGROUND

Patients with sleep apnea and nocturnal brady- and tachyarrhythmia are considered to be patients at especially high risk within the group of all apnea patients.

PATIENTS AND METHODS

13 patients with sleep apnea (apnea-index > 10 events/h), suspected coronary heart disease and known increased frequency of nocturnal premature ventricular contractions (PVC) were studied. Polysomnography, long-term ECG and six-lead ECG were performed.

RESULTS

Within the period studied (1.00 to 6.00 o'clock), an average of 47 PVC per hour was recorded (range 4 to 337/h). In two patients 24 episodes of nocturnal myocardial ischemia were observed, but were not accompanied by PVC. Interestingly only 387 of 1371 premature ventricular contractions (28.2%) were associated to apnea/hyperventilation episodes. Arrhythmia occurred mainly during sleep stages I/II and REM (n.s.). There was a tendency towards more frequent PVC with more pronounced oxygen desaturations.

CONCLUSION

Patients with coronary heart disease, obstructive sleep apnea and severe hyoxemia are at higher risk of developing nocturnal PVC because reduced hypoxic tolerance of the heart may lead to electrical instability.