Changes in the parameters of ventricular repolarization during preapnea, apnea, and postapnea periods in patients with obstructive sleep apnea.

Background: Ventricular arrhythmias are reported to be more common in patients with obstructive sleep apnea (OSA). Preliminary evidence showed such parameters regarding ventricular repolarization as Tp-e, Tp-e/QT, and Tp-e/QTc may be related with increased cardiac arrhythmias and even sudden cardiac death. The purpose of the present study was to evaluate ventricular repolarization during immediately preapnea period, apnea period, and postapnea hyperventilation period in patients with OSA.

Methods: A total of 59 patients who underwent polysomnography and were diagnosed with OSA between the years 2016-2017 in our hospital were included in our study. Of 59 patients (mean age: 52.51 ± 9.66), 28 were male and 31 were female. In all patients, Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio, together with some other parameters, were calculated. Categorical variables were expressed as proportion and continuous variables were expressed as mean ± standard deviation. Electrocardiogram calculations of interest were compared through preapnea, apnea, and postapnea periods using Friedman's test.

Results: Tp-e interval (85.6 ms [78.3-95.6], 98 ms [88.5-107.7], 91.2 ms [81-98.8], respectively; P < 0.001), Tp-e/QT ratio (0.219 [0.202-0.237], 0.242 [0.224-0.269], 0.233 [0.212-0.246], respectively; P < 0.001), and Tp-e/QTc ratio (0.210 [0.190-0.222], 0.233 [0.209-0.247], 0.212 [0.193-0.229], respectively; P < 0.001) were significantly increased during apnea period compared to the preapnea period and significantly decreased during postapnea hyperventilation period compared to the apnea period.

Conclusion: Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were shown to be increased during apnea period and decreased during postapnea hyperventilation period. Our findings may help explain cardiac arrhythmias and sudden death in OSA patients.