Sleep apnea is related to prolonged QT interval and sleep hyperarousal is related to elongated Tp-e interval, regardless of acute autonomic impacts

Sleep apnea is related to prolonged QT interval and sleep hyperarousal is related to elongated Tp-e interval, regardless of acute autonomic impacts

Objective: The aim of this study is to investigate if obstructive sleep apnea (OSA) or hyperarousal is associated with electrocardiac disturbances during ventricular repolarization via acute automatic impacts. Methods: Natural-logarithm-transformed power values of heart rate variability (HRV) parameters were evaluated. In addition, values of heart-rate corrected QT interval (QTc), the interval between peak and end of T wave (Tp-e), and Tp-e/QTc ratio were calculated based on first 5-min arousal-free electrocardiography segment in pre-sleep-wakefulness (AWK), non-rapid-eye-movement stage 2 (N2), slow-wave (N3), and last rapid-eye-movement (REM) sleep from one-night polysomnographic data from 101 otherwise healthy males (43.5±7.9 yrs., 26.7±3.3 kg/m2; 17.7±18.3 and 33.0±17.6/hr apneahypopnea (AHI) and arousal indices (AI), respectively). Results: Using linear regression analysis, QTc and Tp-e of all subjects at various stages were related to AHI and AI, respectively. Systolic, diastolic and mean arterial blood pressures at waking were all lower in low arousal groups than in medium or high arousal groups. There were no differences in blood pressure among the three groups based on AHI. No differences were found in the fluctuation of each HRV parameter across various stages among the three groups by AHI or AI values. QTc values at AWK, N2 and N3 were greater in severe OSA than in control subjects (468±40 vs 431±39; 469±46 vs 430±40; and 472±50 vs 434±41 ms; p values of 0.01, 0.01 and 0.02, respectively). Tp-e values sequentially decreased from high, medium to low arousal in AWK, N2 and N3 (117±15, 107±11, 107±16; 116±13, 108±15, 105±15; and 117±14, 109±14, 107±16 ms; p values of 0.00, 0.01 and 0.02, respectively) but Tp-e/QTc ratios were constant in both groups. Notably, while HRV spectral parameters fluctuated over various pre-sleep wakefulness and sleep stages as previously reported, QTc, Tp-e and Tp-e/QTc ratio remained static. Conclusions: Severe OSA or hyperarousal subjects have a higher risk for ventricular arrhythmia around the clock related to prolonged repolarization and/or depolarization periods of ventricles which most likely results from long-term detrimental effects rather than acute autonomic impacts.