Heart rate changes in relation to sleep stages in patients with obstructive sleep apnea syndrome

BACKGORUND. Obstructive sleep apnea syndrome (OSAS) is a major health problem. The complications of this condition decrease the quality of life. Patients with OSAS present an increased risk of cardiovascular diseases: arterial hypertension, heart failure, myocardial ischemia, myocardial infarction, stroke. MATERIAL AND METHODS. The patients included in the study were divided into 4 groups, depending on the value of the apnea-hypopnea index (AHI): Control Group A with AHI<5; Group B – mild apnea, 5<AHI<15; Group C – moderate apnea, 16<AHI<30; Group D – severe apnea, AHI >30. AHI and heart rate at different sleep stages were correlated. RESULTS. 133 patients were analyzed. The average age was 47 years±15 years, and the gender distribution shows women 21.1% and men 78.9%. The average value of oxygen saturation was 90.45±4.99%. The average value of heart rate during sleep was 104±67.7 beats/minute. The heart rate was variable depending on the sleep stage, with p = 0.0089 regardless of the sleep stage. CONCLUSION. It can be argued that sleep apnea is a factor that interferes with the adaptive mechanisms of heart rate during sleep. Polysomnographic evaluation of sleep stages and clinical examination of patients with OSAS allow the initiation of treatments to prevent the occurrence of cardiovascular diseases.