Arrhythmia and sleep-disordered breathing in patients undergoing cardiac surgery

Recently, the role of sleep-disordered breathing (SDB) in cardiovascular disease has attracted attention. In this study, we investigated the influence of SDB on postoperative arrhythmias after cardiac surgery.

In 89 patients undergoing cardiac surgery, postoperative portable monitoring for SDB and Holter electrocardiography were performed. The primary end-points were the apnea-hypopnea index (AHI) and occurrence of arrhythmia. The secondary end-points were: (1) patient background factors; (2) average heart rate; (3) maximum heart rate (total, daytime, and nighttime); (4) minimum heart rate (total, daytime, and nighttime); (5) minimum SaO(2) during sleep; and (6) an independent predictor for arrhythmia. Twenty-six patients (29.2%) had an AHI≥15 and they were classified into the SDB group, while patients with an AHI<15 formed the non-SDB group (70.8%). Although there was no significant difference in atrial fibrillation, frequent nocturnal premature ventricular contractions were significantly more common in the SDB group (19.2%) than the non-SDB group (3.2%) (p=0.01). Maximum daytime and nighttime heart rates were also significantly higher in the SDB group. AHI was a significant predictor for frequent nocturnal premature ventricular contractions.

This study showed that SDB is common among patients undergoing cardiac surgery, and that SDB might be closely associated with arrhythmia in these patients.