Insomnia and Disorders in Heart Rate Variability in Patients With Coronary Heart Disease and Depressive Disorders

Highlights Patients with coronary heart disease often present with comorbid depressive disorders, insomnia and a significant decrease in heart rate variability, which can aggravate the clinical course of the disease and increase the risk of sudden death. Abstract Aim. To study the presence and severity of insomnia and the range of heart rate variability (HRV), as well as their relationship in a patient with coronary heart disease (CHD) with depressive disorders (DD). Methods. The study included 101 patients with CHD (more than 6 months after myocardial infarction): 67 patients with DD and 34 patients without DD. The Beck Depression Scale consultations with a psychotherapist were used to diagnose DD. Sleep disturbances were assessed using the Sheehan Rating Scale. HRV parameters were assessed using the SCHILLER MT-200 Holter-ECG device. Data are presented as M ± SD; n (%); Me [25%; 75%], tables of connectivity and χ2 criteria were used. The difference was considered significant at p <0.05. Results. Sleep disturbances and night awakenings in the general group of patients occurred in the following cases: none or clinically not significant – 50 (49.5%) cases, clinically significant – 51 (50.5%) cases. Sleep disturbances and night awakenings were significantly pronounced in CHD patients with DD compared with patients without DD: clinically significant sleep disturbances in 45 vs 6 patients (p = 0.00001), night awakenings – 43 vs 8 patients (p = 0.003), respectively. In patients with DD, compared to patients without DD, a significant decrease in HRV was noted in the following parameters: SDNN (97 [83; 113] ms vs 110 [98; 124] ms, p = 0.01), SDANN 80 [67; 94] ms vs 91 [79; 102] ms, p = 0.01), SDNN index (46 [38; 56] ms vs 55 [48; 66] ms, p = 0.005), pNN50% (4 [2.4; 5.7] vs 6 [ 3; 12.6], p = 0.02). There was a more significant decrease in the SDNN index in patients with severe sleep disturbances, compared with patients with normal sleep (38 [34; 51] ms vs 57 [48; 61] ms, p = 0.02). Conclusion. Changes in the circadian rhythm in CHD patients with DD take the form of insomnia and a significant decrease in HRV. Insomnia increases sympathetic activation, which aggravates the clinical course of CHD and increases the risk of sudden death due to arrhythmias.