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Effects of continuous positive airway pressure on sleep apnea and ventricular irritability in patients with heart failure.

BACKGROUND
Patients with heart failure and systolic dysfunction may develop disordered breathing during sleep. Repeated episodes of apnea and hypopnea may result in desaturation and arousals, which could adversely affect left ventricular function. The purpose of this study was to determine the short-term effects of continuous positive airway pressure (CPAP) on sleep-disordered breathing and its consequences in heart failure patients.


METHODS AND RESULTS
The author prospectively studied 29 male patients whose initial polysomnograms showed 15 or more episodes of apnea and hypopnea per hour (apnea-hypopnea index, AHI). Twenty-one patients had predominately central and 8 patients obstructive sleep apnea. All were treated with CPAP during the subsequent night. In 16 patients, CPAP resulted in virtual elimination of disordered breathing. In these patients, the mean AHI (36+/-12 [SD] versus 4+/-3 per hour, P=0.0001), arousal index due to disordered breathing (16+/-9 versus 2+/-2 per hour, P=0.0001), and percent of total sleep time below saturation of 90% (20+/-23% to 0.3+/-0.7%, P=0.0001) decreased, and lowest saturation (76+/-8% versus 90+/-3%, P=0.0001) increased with CPAP. In 13 patients who did not respond to CPAP, these values did not change significantly. In patients whose sleep apnea responded to CPAP, the number of hourly episodes of nocturnal premature ventricular contractions (66+/-117 versus 18+/-20, P=0.055) and couplets (3.2+/-6 versus 0.2+/-0.21, P=0.031) decreased. In contrast, in patients whose sleep apnea did not respond to CPAP, ventricular arrhythmias did not change significantly.


CONCLUSIONS
In 55% of patients with heart failure and sleep apnea, first-night nasal CPAP eliminates disordered breathing and reduces ventricular irritability.