Clinical Electrophysiology -> Ventricular Arrhythmias -> Electrocardiography D-PO05 - Poster Session V (ID 39) Poster

D-PO05-234 - Non-invasive Assessment Of Ventricular Repolarization During Oxygen Desaturations Caused By Sleep Apnea (ID 1322)


Background: Obstructive sleep apnea/hypopnea syndrome (OSA) has been associated with nocturnal sudden cardiac death, and prolongation in QTc has been suggested as a potential mechanistic link. Whether the ventricular repolarization changes are correlate with the intensity of acute oxygen desaturation remains unknown.
Objective: Determine whether OSA episodes with greater acute oxygen drop manifest greater change in QTc compared to episodes with lesser oxygen drop.
Methods: Sleeping patients with mild-moderate OSA without cardiac medications were studied during overnight polysomnography by signal-averaged 8-lead ECG recording. Acute changes in ventricular repolarization were measured during isolated OSA episodes, and the characteristics of OSA episodes (type, duration, oxygen desaturation) that induced the greatest ECG changes were identified.
Results: We studied 144 isolated OSA episodes in 11 patients (5 women, age 59.1 ± 4.5 years, apnea hypopnea index 13.5 ± 1.0). QTc increased from 442±62 (pre-episode baseline) to 460±50 (during OSA release, p<0.0001). Maximum increase in QTc was significantly greater during OSA episodes with greater acute oxygen drop (Figure; p=0.0065), and this difference remained significant in a multi-variate analysis after accounting for OSA episode length.
Conclusion: The magnitude of acute oxygen drop is a relevant variable when assessing the influence of OSA on QTc. These findings open the possibility of a weighted, more individualized score of OSA severity which would be more closely aligned with proposed pathophysiological links between OSA and sudden death.