Sleep-disordered breathing and electrocardiographic QRS-T angle: The MESA study

Introduction: Sleep-disordered breathing (SDB) has been linked to sudden cardiac death (SCD) but the mechanism is unclear. Abnormal QRS-T angle, a novel electrocardiographic (ECG) marker of ventricular repolarization, has been linked to adverse cardiovascular outcomes including SCD. We hypothesized that individuals with SDB have more pronounced abnormality in QRS-T angle. Methods: We performed a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis (MESA) Exam Sleep ancillary study. We calculated the odds ratio (OR) of abnormal frontal and spatial QRS-T angle (defined as >sex-specific 95th percentile thresholds) related to the apnea–hypopnea index (AHI) using logistic regression, adjusting for demographics, body habitus, cardiovascular risks, and prevalent cardiovascular disease. Linear associations between AHI and frontal and spatial QRS-T angle, separately, were also examined using multiple regression models. Results: A total of 1,804 participants (mean age 67.9 (±9.0) years, 55.3% women and 64.1% non-whites) were included in the study. Sleep-disordered breathing was common among participants (median AHI 8.6 events/hr IQR [3.2–19.5/hr]). Higher AHI was associated with the odds of abnormal frontal (≥81° in men and ≥79° in women) and spatial QRS-T angle (≥129.7° in men and ≥115.9° in women; OR [95%CI]: 1.25 [1.02–1.51], p = 0.03; 1.23 [1.01-1.50], p = 0.04 respectively per 1 SD [16.8 events/hr] increase in AHI). Similarly, linear associations were observed (frontal QRS-T angle: beta coefficient: 2.30° [0.92, 3.66], p = 0.001; spatial QRS-T angle: beta coefficient: 2.16° [0.67, 3.64], p = 0.005). Conclusion: In a racially/ethnically diverse community cohort, severity of SDB is associated with abnormal ventricular repolarization as measured by QRS-T angle.