Heart rate variability, t wave alteration and prolonged qt interval as markers of arrhythmogenesis in patients with sleep apnea syndrome and arterial hypertension

Introduction Many researches have provided evidence supporting the associations between obstructive sleep apnea (OSA) with cardiovascular morbidity and mortality. But underlying mechanisms explaining these associations are not entirely delineated. Materials and methods Cross-sectional study of 58 patients, aged 45–65 years old, 29 males and 15 females with arterial hypertension, who underwent Holter ECG with rheopneumogram. Demographics, cardiovascular risk factors, heart rate variability, QT intervals, microvolt T wave alteration were examined. Patients were divided in three groups according to sleep apnea hypopnea index (AHI): group 1 (AHI  n  = 15), group 2 (AHI  = 5–29, n  = 12), group 3 (AHI > 30, n  = 11). Control group – 20 patients without breath disturbances. Results Positive test on microvolt T wave alteration was found in 36.3 % patients with severe and 41.6 % moderate OSA and in 1 patients of control group. Decreased heart rate variability, predominating of sympathetic activity, rigid rhythm, transient prolonged QT interval especially at night were common for patients with severe and moderate OSA. Significant positive correlation was found between AHI and QT interval ( p  = 0.03, r  = 0.3), QTc interval ( p  = 0.04, r  = 0.5), negative correlation between AHI and SDNN ( p  = 0.04, r  =  −0.3). Conclusion Decreased heart rate variability, predominating of sympathetic activity, prolonged QT interval and T wave alteration are important background for fatal arrhythmias and predictors of sudden cardiac death in patients with OSA. Acknowledgement Thank You for a possibility to deal with my modest research.