Study of electrocardiographic indices of myocardial repolarization in patients with obstructive sleep apnea

Background Obstructive sleep apnea (OSA) is a sleep disorder manifested by airflow severe reduction or stoppage during breathing exertion. OSA cases had a higher incidence of ventricular arrhythmias, according to reports. Aim This research aimed to determine ventricular repolarization in OSA cases using the electrocardiographic indices of ventricular repolarization. Patients and methods This observational research involved 60 patients who underwent overnight polysomnography (PSG). 20 cases with normal PSG were employed as controls. Moderate or severe OSA cases were employed as study group. Tp-e, QTc intervals & Tp-e/QTc ratios measurement was performed in all patients. Results Patients had significantly prolonged QTc intervals, Tp-e intervals & Tp-e/QTc ratio compared to controls (446.4 +/- 36.99 ms vs. 408.6 +/- 25.23 ms, 86.12 +/- 17.63 ms vs. 66.65 +/- 15.49 ms & 0.19 +/- 0.04 vs. 0.16 +/- 0.04 respectively, P<0.001). There was a significant positive correlation between OSA degree and Tp-e/QTc ratio (r=0.374, P=0.017), Tp-e/QT ratio (r=0.448, P=0.004) & Tp-e interval (r=0.377, P=0.016). There is also significant correlation between such repolarization indices and both lowest SpO2 and arousal index (P<0.05). Conclusions We concluded a significant positive correlation between OSA degree and Tp-e/QTc, Tp-e/QT ratios & Tp-e interval. OSA is associated with prolonged Tp-e/QTc & Tp-e/QT ratios and a prolonged Tp-e interval.