Sleep disordered breathing in coronary heart disease patients with mild and moderate heart failure

Abstract

The purpose of the study was to investigate the relationship between sleep disordered breathing (SDB) and degree of heart failure (HF) in patients with coronary heart disease (CHD). A total of 3017 patients (77.4% men and 22.6% women) were included in the study. Clinical examination and echocardiography for evaluation of HF using NYHA functional classification and sleep polysomnography were performed. The study demonstrated that SDB is more common in CHD patients with higher NYHA functional class. The prevalence of central sleep apneas against obstructive apneas was observed in patients with mild and moderate HF. The number of central apneas was strongly related to the severity of heart failure. More frequent appearance of central sleep apneas is predominantly due to instability of ventilatory control systems during sleep because of impaired cardiac function in HF patients. Sleep architecture was more disturbed in CHD patients with higher NYHA functional class. A gradual increase of stage 1 and wakefulness after sleep onset and a decrease of sleep stages 3-4 and REM sleep as well as a diminution of sleep efficiency with worsening of NYHA functional class were observed. We suggest that both SDB and disturbed sleep variables independently significantly correlate with manifestation of HF.