Analysis of Corrected QT Interval Dispersion (QTcd) in Normotensive Subjects Performing Breath-hold Challenge

Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a disorder in which the airway is blocked completely (apnea) or partially (hypopnea), and is caused by the collapse of the pharyngeal wall during sleep. Marked cardiovascular changes are correlated with the onset of apneic events and post-termination, including changes in the electrocardiogram (ECG) interval durations. The breath-hold challenge is a well-documented maneuver that simulates the cardiovascular changes seen in OSAHS. In this study, we present preliminary results of the changes in QTc interval and QTc dispersion in for eight volunteers (3 females, aged 27.00±5.68 years, BMI 24.14±5.11 kg/m2) undergoing the breath-hold challenge in the supine position. We use a previously developed algorithm to detect the different waveforms in the ECG signal and calculated QT and QTc intervals. Results were analyzed for the QTc signal range, skewness, and kurtosis. Further analysis of the dispersion of the QTc (QTcd) signal shows a marked change in QTcd in correlation with the onset of the event and the intra-breath-hold breathing. These results indicate the possibility to explore the QTcd signal in the detection of OSAHS using single-lead ECG.