Role of cardiac pacing in sleep apnea uncertain. Article reviewed: S. Garrigue, P. Bordier, P. Jais, et al., Benefit of atrial pacing in sleep apnea syndrome, N Engl J Med, 346 (2002) 404-412.

摘要

OBJECTIVES: To determine the effect of atrial overdrive pacing on sleep apnea severity in patients with sinus node dysfunction.STUDY DESIGN: Unblinded, cross-over study of the effect of atrial pacing on sleep apnea-hypopnea, with randomized order of study conditions (paced versus unpaced).STUDY POPULATION: Fifteen patients (11 men, 4 women), mean age 69 (SD 9) years, with sinus node dysfunction and permanent dual-chamber pacemakers, with polysomnographic evidence of either central or obstructive sleep apnea-hypopnea (mean apnea-hypopnea index (AHI) 27 (SD 16)). None had symptomatic heart failure, but 11 (73%) had mildly reduced left ventricular ejection fraction (40-56%).METHODS: One hundred and fifty-two patients with pacemakers implanted at least one year previously for symptomatic sinus node dysfunction (including tachycardia-bradycardia syndrome) were screened for symptoms of sleep apnea. Of 47 patients identified, 26 underwent polysomnography and 15 had an apnea index >5/h and an AHI >15/h. Following the baseline polysomnogram, subjects underwent polysomnography on the subsequent two nights under the following conditions, in random order: (1) pacemaker set at a rate 15beats/min higher than the mean heart rate of the diagnostic study (overdrive pacing phase); and (2) pacemaker rate reduced to 40beats/min (no-pacing phase). The main outcome measure was the difference in AHI between the two pacing modes.RESULTS: Mean nocturnal heart rate during the pacing phase was 72/min, versus 51/min during the no-pacing phase. During the no-pacing phase, AHI was unchanged from the baseline night at 28/h (SD 22). During overdrive pacing, however, the AHI was 61% lower at 11/h (SD 14). The AHI was lower on the pacing than the no-pacing night in all 15 subjects, regardless of whether the predominant type of apnea was central or obstructive. The mean central apnea index fell from 13 (SD 17) to 6 (SD 7), and the obstructive apnea index from 6 (SD 4) to 3 (SD 1). Both lowest oxyhemoglobin saturation and the percent time at saturation below 90% also improved on the pacing night. There was little difference in total sleep time between pacing and no-pacing nights; other measures of sleep quality were not reported.CONCLUSIONS: The authors conclude that atrial overdrive pacing at a relatively modest rate causes a substantial improvement in both central and obstructive sleep apnea, by mechanisms that are uncertain.