Badanie przesiewowe pacjentów z chorobą wieńcową w kierunku obturacyjnego bezdechu sennego i ocena jego wpływu na zmienność rytmu zatokowego

Abstract

Introduction. Obstructive sleep apnea (OSA) is one of the most common sleep disorders, which affects 4% of men and 2% of women in the world population. The disorder can be diagnosed in men and women of all ages; however, its incidence increases with age. Patients with OSA experience increased levels of sympathetic nervous system activity, which is evidenced by the increased catecholamines secretion. They are at an increased risk of developing complications of coronary heart disease (CHD). The aim of the study was to evaluate the influence of results of screening for OSA on the activity of the sympathetic and parasympathetic nervous systems within the scope of selected heart rate variability (HRV) parameters (time-domain and frequency-domain analyses of the HRV) in patients with CHD. Material and methods. Holter recordings of 146 patients aged 43–78 (106 of whom were men) were analysed retrospectively. The patients were divided into four groups on the basis of the estimated apnea–hypopnea index (eAHI), assessed by means of 24-hour recordings of electrocardiogram with Lifescreen Apnea software: < 5 (control group), from 5 to < 15 (mild), from 15 to < 30 (moderate) and ≥ 30 episodes (severe). For each patient, a profile of power spectrum alterations was developed for low frequency (LF) and high frequency (HF) in 60-minute periods between 10 p.m. and 6 a.m. and standard deviation of RR intervals (SDNN) and root mean square of successive differences (rMSSD) values were calculated. The power spectrum in the consecutive one-hour periods was averaged in both groups. In view of the right-skewed distribution of data, the average power spectra were converted into natural logarithms. In order to assess the significance of variations, the natural logarithms of the average values were compared using the univariate analysis of variance (ANOVA). Results. In the examined groups, there were statistically significant differences in the HF band of power spectrum between the control group and the group of patients with mild OSA (p < 0.01), those with severe OSA (p < 0.01) and also between the group with mild and moderate OSA (p < 0.01). In the LF band of power spectrum, the only difference was seen between the group of patients with mild OSA and those with moderate OSA (p < 0.01). In the time-domain analysis of HRV (SDNN, rMSSD), no statistically significant differences between the groups were observed. Conclusions. High frequency band of power spectrum [HF] in frequency-domain HRV analysis could be a more effective parameter to distinguish patients with mild OSA (from 5 to < 15) and severe OSA (≥ 30) in patients suffering from CHD, than the power spectrum for LF or SDNN and rMSSD.