Abstract 13421: Prognostic Significance of QRS-T Angle in Middle-Aged General Population
Introduction: QRS-T angle (either planar or spatial) measured from a standard 12-lead electrocardiogram (ECG) has been shown to predict mortality in various patient and general populations. Because of the known gender related differences in QRS-T angle, we assessed the prognostic significance of QRS-axis, T-wave axis and QRS-T angle in a population based cohort of middle-aged females and males with a long follow-up.
Methods: ECGs were recorded in 5619 males (52%) and 5131 females (48%) between 1966–1972. The mean age of the population was 44±8yrs. Specially trained nurses or technicians performed the baseline examinations and analyzed the ECGs which were transferred to electronic database for further use. QRS-T angle was categorized as normal (0–100°) or abnormal (>100°), and QRS- and T-wave axes as normal (0–100°) or abnormal (>100° or <0°). Analyses were performed separately for females and males. The primary end-points were all-cause mortality, cardiac mortality and arrhythmic death.
Results: During the mean follow-up of 30±11 years, total mortality was 56.5% (6133 subjects). Cardiac mortality was 32.1% (1969 subjects) and 40.4% (795) of them were defined as arrhythmic deaths according to the CAST/CAPS-study criteria. Abnormal QRS-T angle was associated with increased risk of all-cause (adjusted hazard ratio [HR] 1.77, 95%CI 1.45–2.15) and cardiac mortality in males (HR 2.04, 95%CI 1.51–2.76), but not in females (NS for both end-points). Wide QRS-T angle was a strong predictor of arrhythmic death in both genders (RR 2.33, 95%CI 1.54–3.51 for males and RR 2.15, 95%CI 1.01–4.57 for females). Prognostic significance of wide QRS-T was mainly due to abnormal T-wave axis, which also predicted arrhythmic death both in males (RR 2.27, 95%CI 1.65–3.12) and females (RR 1.74, 95%CI 1.06–2.86). QRS-axis had no prognostic power.
Conclusions: Wide QRS-T angle measured from standard 12-lead ECG increases the risk of arrhythmic death in both genders. Prognostic importance of abnormal QRS-T angle is mainly a result of altered T-wave axis.
- © 2010 by American Heart Association, Inc.