Effects of cardiac resynchronization therapy on sleep apnea, quality of sleep and daytime sleepiness in patients with chronic heart failure

Sleep-related breathing disorders are common in patients with chronic heart failure (CHF) and contribute to exacerbation of CHF. The effects of biventricular stimulation (CRT) seem to exceed the improvement of mechanical heart performance and are likely to affect other aspects of CHF pathophysiology. The aim of the study was to assess the influence of CRT on subjective and objective sleep features.Twenty seven consecutive patients (aged 67.7 +/- 8.7 years, 23 men - 85%) with chronic heart failure (62.9% with ischaemic background and 37.1% of non-ischaemic etiology) in stable for at least 3 months NYHA class III - IV despite optimized pharmacotherapy, with left ventricular end-diastolic diameter (LVEDd) > 55 mm, left ventricular ejection fraction (LVEF) < or = 35% and wide QRS complex (> or = 120 ms) were appraised before and 12-16 weeks after CRT introduction clinically (including 6-minute walk test--6-MWT), echocardiographically and in polisomnography. The apnea-hypopnea index (AHI) and apnea indexes (AI) of central, obstructive and mixed types were calculated. The sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI), daytime sleepiness with the Epworth Sleepiness Scale (ESS).LVEF increased, 6-MWT distance rose. Left ventricular diameters and left ventricular end-systolic volume decreased. PQSI and ESS fell (9.3 +/- 4.2 vs 6.2 +/- 3.2, p < 0.001 and 8.4 +/- 4.1 vs 7.0 +/- 3.4, p < 0.001, respectively). AHI, obstructive AL and mixed AL did not alter but significant reduction of central AL was noted (9.6 +/- 13.0 vs 3.7 +/- 6.2, p = 0.023).CRT decreases central sleep apnea and improves quality of sleep and daytime sleepiness in patients with CHF.