Background: Patients with heart failure (HF) often complain of sleep discomfort. Previous reports described that difficulty initiating sleep increased the cardiovascular risk in the general population. However, the association between difficulty initiating sleep and cardiac function in patients with HF remains unclear. This study aimed to investigate the associations between difficulty initiating sleep and clinical characteristics and cardiac function in patients with HF.
Methods: Eighty-seven patients with HF who underwent overnight polysomnography for suspected sleep-disordered breathing were included. Patients were divided into two groups of the longer sleep latency (SL) group (SL ≥14 min, n = 44) and the shorter SL group (SL <14 min, n = 43). The median value of SL was defined as the time from lights-off to falling asleep. We compared the patients' characteristics, laboratory data, and polysomnographic and echocardiographic indices between the two groups.
Results: The patients' median age was 67 years, and 85.1 % were men. There was lower beta blocker use [25 (56.8 %) vs. 34 (79.1 %), p = 0.046] and a higher peak mitral early filling velocity to mitral annular velocity ratio (E/e') [16.5 (14.2-21.7) vs. 13.7 (10.9-16.2), p = 0.005] in the longer SL group than in the shorter SL group. In multivariate logistic analysis, E/e' (odds ratio: 1.10, 95 % confidence interval: 1.01 to 1.19; p = 0.032) and systolic blood pressure before sleeping (odds ratio: 1.05, 95 % confidence interval: 1.00 to 1.10; p = 0.033) were significantly associated with a longer SL in patients with HF.
Conclusions: Increased left atrial pressure suggested by increased E/e' and increased systolic blood pressure before sleeping is independently associated with difficulty initiating sleep in patients with HF. Management of these hemodynamic imbalances is required to improve difficulty initiating sleep in patients with HF.
Keywords: Heart failure; Left atrial pressure; Sleep latency.
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