[Prevalence of obstructive sleep apnea syndrome in patients with sick sinus syndrome]

Sleep apnea-hypopnea syndrome (SAHS) has been associated with different cardiovascular diseases. It may even be implicated in the pathophysiology of sick sinus syndrome (SSS). However, the precise relationship between the two syndromes is still unknown. We investigated the prevalence of SAHS in patients diagnosed with SSS.

Between June 2002 and December 2004, 38 consecutive patients who were diagnosed with SSS by 24-hour Holter monitoring were studied prospectively in our institution. All patients were asked about symptoms of SAHS, and underwent polysomnography out of hospital using a validated monitor.

The patients' mean age was 67 (10) years, 68% were male, and 58% were hypertensive. Holter monitoring demonstrated a maximum heart rate of 87 (6) beats/min, a minimum of 35 (3) beats/min, and a mean of 48 (3) beats/min. Some 24 (63%) patients required pacemaker implantation because of symptomatic SSS. Overall, 39% of patients had symptoms suggestive of SAHS (i.e., an Epworth index or EI>9). Polysomnography showed that only 13% of patients had a normal apnea-hypopnea index (AHI) and that 31.6% (95% CI, 16.8%-46.4%) had SAHS (i.e., AIH>10 and EI>9).

Given that the prevalence of SAHS in the general population is around 3%, our results indicate that it is ten-fold higher in patients with SSS than in the general population. This observation indicates that there may be a relationship between the two syndromes.