Short-term effects of cardiac resynchronization therapy on sleep-disordered breathing in patients with systolic heart failure

Objectives: We evaluated the short-term effect of cardiac resynchronization therapy (CRT) on sleep apnea in patients with systolic heart failure. Background: Sleep-disordered breathing is common in patients with left ventricular systolic dysfunction. Methods: Twelve patients (mean [± SE] age, 59.6 ± 7.8 years; mean left ventricular ejection fraction, 28.0 ± 2.8%) with an implanted atrial-synchronized biventricular pacemaker for the treatment of left ventricular systolic dysfunction were selected and studied. Each subject underwent polysomnography on 3 consecutive nights with CRT on the first night, CRT off the second night, and CRT on the third night. Echocardiography was performed prior to each polysomnogram. Results: The central sleep event index (ie, the number of central sleep apneas [CSAs] and hypopneas per hour of sleep) score was lower with CRT compared to that without CRT (mean central sleep event index score with CRT on, 6.9 ± 1.7 events per hour of sleep; mean central sleep event index score with CRT off, 14.3 ± 2.9 events per hour of sleep; mean central sleep event index score with CRT on, 8.1 ± 1.5 events per hour of sleep; p < 0.001). Similarly, the cumulative duration of central sleep events (the number of minutes per hour of sleep during CRT) was one half that observed without CRT (CRT on, 2.8 ± 0.7 min per hour of sleep; CRT OFF 6.2 ±1.2 min per hour of sleep; CRT ON 3.1 ± 0.7 min per hour of sleep; p < 0.001). There was a significant correlation between mitral regurgitant volume and central sleep event index on all three nights (r > 0.77; p < 0.01). Conclusions: CRT reduces CSA severity in the short term. This reduction correlated significantly with the CRT-mediated reduction of mitral regurgitation.