UC San Diego

Background

Information is limited about the independent prognostic value of repolarization abnormalities in women.

Methods and results

We evaluated hazard ratios for ECG variables for combined fatal and nonfatal coronary heart disease (CHD) events and for CHD mortality using Cox regression in 38,283 Women's Health Initiative (WHI) participants during up to 9.2 years of follow-up. All risk models were adjusted for demographic, clinical, and therapeutic variables. Evaluated as single ECG variables, wide QRS/T angle and ECG-demonstrated myocardial infarction (ECG-MI) were the strongest predictors of CHD events, with hazard ratios (95% CI) of 1.90 (1.50 to 2.42) and 1.62 (1.29 to 2.03), respectively. Six other repolarization variables were also significant, strong predictors of CHD events. Wide QRS/T angle, ECG-MI, and QT prolongation appeared as dominant predictors when evaluated simultaneously with other ECG variables in a multiadjusted risk model. QRS/T angle, ECG-MI, and high QRS nondipolar voltage were the strongest predictors of CHD mortality, with hazard ratios of 2.70, 2.41, and 2.18, respectively. The risk increase ranged from 63% to 95% for the other 4 significant predictors. Five ECG abnormalities were identified as dominant mortality risk predictors: wide QRS/T angle, ECG-MI, high QRS nondipolar voltage, reduced heart rate variability, and QT prolongation (in the cardiovascular disease-free group only).

Conclusions

Ventricular repolarization abnormalities in postmenopausal women are as important predictors of CHD events and CHD mortality as ECG-MI and other QRS abnormalities. Repolarization variables and QRS nondipolar voltage warrant attention in future investigations.