Obstructive sleep apnea and increased QT dispersion

Abstract

Exaggerated dispersion of repolarization is likely to play a role in both the initiation and the maintenance of malignant ventricular arrhythmias. Interlead QT interval differences within a 12-lead electrocardiogram (ECG), termed “QT dispersion”, may reflect regional differences in myocardial refractoriness. Presumably, abnormal QT dispersion may be related to obstructive sleep apnea (OSA). This work aimed to provide a meta-analysis of the relevant available publications. A MEDLINE search was performed in PubMed (National Library of Medicine, NLM) from 2000 through to 2014. An all-fields search for index terms “QT” AND “dispersion” was conducted. Case–control studies and surveys were included into analysis, provided they encompassed healthy controls and subjects with diagnosed OSA, without other major health problems. Outcome measures were either crude (QTd) or heart rate-corrected (QTcd) dispersions. Four studies met the inclusion criteria. Overall, the analysis encompassed 222 patients with diagnosed OSA and 182 control subjects. Mean calculated age of the OSA patients was 37.7 years (standard error, SE: 11.5 years). Aggregate standardized difference in the means of QTd was 0.571 (95 % confidence interval, CI: 0.354–0.789; SE = 0.111, p < 0.001); for QTcd the difference was 0.859 (95 % CI: 0.142–1.577; SE = 0.366, p = 0.019). Meta-regression analysis found a statistically significant negative correlation between the effect sizes and the proportion of males in the OSA group. OSA is associated with increased QT dispersion. This may reflect disturbed myocardial repolarization in patients with OSA and predispose them to cardiac arrhythmias.