Wide QRS-T Angle on the 12-Lead ECG as a Predictor of Sudden Death Beyond the LV Ejection Fraction

Introduction: Improvements in risk stratification for sudden cardiac arrest (SCA) will require discovery of markers that extend beyond the LV ejection fraction (LVEF). The frontal QRS-T angle has been shown to predict risk of SCA but the value of this marker independent of the LVEF has not been investigated. Methods and Results: Cases of adult SCA with an archived electrocardiogram (12-lead ECG) available before the event, with a computable frontal QRS-T angle, were identified from the Oregon Sudden Unexpected Death Study (Oregon SUDS) ongoing in the Portland, Oregon metro area. A total of 666 SCA cases (mean age 67.2 years; 95% CI, 52.3–82.1 years; 68.6% males) were compared to 863 controls (mean age 66.6 years, 55.2–78.0 years; 68.1% males; 75.0% had CAD) from the same geographical region. The mean frontal QRS-T angle was wider in cases (74^o; 95% CI, 17^o–131^o) compared to controls (51^o; 95% CI, 5^o–97^o; P< 0.0001). A frontal QRS-T angle of more than 90^o remained associated with increased risk of SCD after adjusting for age, gender, heart rate, prolonged intraventricular conduction, electrocardiographic left ventricular hypertrophy (ECG LVH), baseline comorbidities, and left ventricular ejection fraction (LVEF) (OR 2.2; 95% CI, 1.60–3.09; P< 0.0001). Conclusion: A wide QRS-T angle greater than 90^o is associated with an increased risk of SCA independent of the left ventricular ejection fraction.