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

Area of Science:

• Cardiology
• Sleep Medicine
• Electrocardiography

Background:

• Sleep-disordered breathing (SDB) is a known risk factor for sudden cardiac death (SCD), but the underlying mechanisms remain unclear.
• Abnormal QRS-T angle, an electrocardiographic (ECG) marker of ventricular repolarization, is associated with adverse cardiovascular outcomes, including SCD.

Purpose of the Study:

• To investigate the association between the severity of sleep-disordered breathing (SDB) and abnormalities in the QRS-T angle.
• To determine if individuals with SDB exhibit more pronounced deviations in ventricular repolarization as measured by the QRS-T angle.

Main Methods:

• Cross-sectional analysis of 1,804 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) Exam Sleep ancillary study.
• Calculation of odds ratios for abnormal frontal and spatial QRS-T angles based on apnea-hypopnea index (AHI) using logistic regression.
• Adjustment for demographics, body habitus, cardiovascular risk factors, and prevalent cardiovascular disease; linear associations examined via multiple regression.

Main Results:

• Higher AHI was significantly associated with an increased odds of abnormal frontal and spatial QRS-T angles (OR: 1.25 and 1.23, respectively, per 1 SD increase in AHI).
• Significant linear associations were observed between AHI and both frontal (beta: 2.30°) and spatial (beta: 2.16°) QRS-T angles.
• Sleep-disordered breathing was common in the study cohort, with a median AHI of 8.6 events/hr.

Conclusions:

• The severity of sleep-disordered breathing is significantly associated with abnormal ventricular repolarization, as indicated by QRS-T angle measures.
• These findings suggest that altered ventricular repolarization may be a key mechanism linking SDB to increased cardiovascular risk.