Effect of insomnia and excessive daytime sleepiness on cardiac functions in older adults

We investigated the potential harmful effect in older adults of insomnia and excessive daytime sleepiness (EDS) on myocardial functions and electrophysiologic changes of the heart in terms of heart rate and QT intervals corrected for heart rate (QTc).

The study included 32 insomnia patients and 30 control subjects. An Insomnia Severity Index score of ≥15 indicated insomnia, while a score of <8 was accepted as the control group. The Epworth Sleepiness Scale was used to assess EDS, with a score of ≥11/24 points indicating EDS. Diastolic and systolic functions were evaluated in each patient by transthoracic two-dimensional, conventional and tissue Doppler echocardiography. Heart rate and QTc were calculated for electrophysiologic changes.

The mean age was 73.2 ± 7.9 years, with 59.7% being female. Biventricular systolic and diastolic functions were impaired in the insomnia patients. The E' value for diastolic function was lower in the patients with insomnia than the controls (5.99 ± 1.59 vs. 6.88 ± 0.97, P = 0.053). Furthermore, values for the systolic function parameters Lateral-S (7.41 ± 1.92 vs. 9.37 ± 1.83, P < 0.001), Septal-S (6.69 ± 1.40 vs. 8.10 ± 1.30, P = 0.001), and Tricuspid-S (12.25 ± 2.00 vs. 14.37 ± 3.13, P = 0.004) were lower for insomnia patients than for controls. In the case of EDS coexistence, the heart rate and QTc values were higher than the controls (76.47 ± 7.18 vs. 71.03 ± 10.95, P = 0.001, and 413.72 ± 28.24 vs. 394.67 ± 24.47, P = 0.015, respectively).

Insomnia is associated with impaired systolic-diastolic functions, independent of EDS. The co-existence of insomnia and EDS may lead to electrophysiological changes in older adults, including increased heart rate and longer QTc.