Electrocardiographic Repolarization‐Related Variables as Predictors of Coronary Heart Disease Death in the Women's Health Initiative Study

BACKGROUND: We evaluated 25 repolarization‐related ECG variables for the risk of coronary heart disease (CHD) death in 52 994 postmenopausal women from the Women's Health Initiative study. METHODS AND RESULTS: Hazard ratios from Cox regression were computed for subgroups of women with and without cardiovascular disease (CVD). During the average follow‐up of 16.9 years, 941 CHD deaths occurred. Based on electrophysiological considerations, 2 sets of ECG variables with low correlations were considered as candidates for independent predictors of CHD death: Set 1, Ѳ(T(p)|T(ref)), the spatial angle between T peak (T(p)) and normal T reference (T(ref)) vectors; Ѳ(T(init)|T(term)), the angle between the initial and terminal T vectors; STJ depression in V6 and rate‐adjusted QT(p) interval (QT(pa)); and Set 2, TaVR and TV1 amplitudes, heart rate, and QRS duration. Strong independent predictors with over 2‐fold increased risk for CHD death in women with and without CVD were Ѳ(T(p)|T(ref)) >42° from Set 1 and TaVR amplitude >−100 μV from Set 2. The risk for these CHD death predictors remained significant after multivariable adjustment for demographic/clinical factors. Other significant predictors for CHD death in fully adjusted risk models were Ѳ(T(init)|T(term)) >30°, TV1 >175 μV, and QRS duration >100 ms. CONCLUSIONS: Ѳ(T(p|)T(ref)) angle and TaVR amplitude are associated with CHD mortality in postmenopausal women. The use of these measures to identify high‐risk women for further diagnostic evaluation or more intense preventive intervention warrants further study. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000611.