Sleepiness and activity in heart failure patients with reduced ejection fraction and central sleep-disordered breathing

Abstract Objective Patients with heart failure (HF) and sleep disordered breathing (SDB) are typically not sleepy, unlike patients without heart failure. Previous work in HF patients with obstructive SDB suggested that sleepiness was associated with a reduction in daytime activity. The consequences of predominately central SDB on sleepiness in HF are less well understood. The aim of this study was to test the hypothesis that subjective sleepiness is associated with reduced daytime activity in HF patients with central SDB, compared to those without SDB. Methods The Epworth Sleepiness Scale (ESS), nocturnal polysomnography, and 14 days of wrist watch actigraphy were used to assess subjective daytime sleepiness, nocturnal sleep and breathing, and 24-hour activity levels, respectively. Results A total of 54 patients with HF were studied, 9 with obstructive SDB and were removed from further analysis. Of the patients, 23 had HF with predominantly central SDB (HF-CSA; apnea−hypopnea index (AHI) median 20.6 (IQR 12.9−40.2)/h), and 22 had no SDB (HF-noSDB; AHI 3.7 (2.5−5.9)/h). The median patient age was 68 years (range 59−73 years). There were no significant differences either ESS in score (HF-CSA; 8 [4−10] vs. HF-noSDB; 8 (6−12); p = 0.49) or in duration of daytime activity (HF-CSA 14.5 (14.1−15.2) and HF-noSDB 15.1 (14.4−15.3) hours; p = 0.10) between the groups. Conclusion HF patients with predominately central SDB are not subjectively sleepy compared to those without SDB, despite reduced sleep quality. We speculate that the lack of sleepiness (based on ESS score) may be due to increased sympathetic nerve activity, although further studies are needed due to the small number (n = 5) of sleepy HF-CSA patients. Daytime activity was not different between HF-noSDB and HF-CSA patients.