Electrocardiographic Predictors Coronary Heart Disease Death

Synopsis

In many industrialized countries including the US cardiovascular disease (CVD) continues to be the leading cause of death. Women have been increasingly included in CVD intervention efforts but substantial gender differences still remain in CVD prevalence and mortality. Annual number of adults with diagnosed heart attack of fatal coronary heart disease (CHD) occurs 10 years later in women than in men. Differences in population demographics account for the fact that in terms of absolute numbers more women are living with and dying from CVD including stroke than men, and more women than men are discharged from hospitals with diagnosis heart failure and stroke. These facts emphasize the need for identification of improved ECG predictors for CVD death and HF.

In the WHI study in post-menopausal women the main independent predictors of CHD death were Ѳ(T_p|T_ref), the spatial angle between the Tpeak (Tp) vector and the reference vector for normal repolarization (Rfef) and TaVR amplitude, with an over twofold increased risk for both. Ѳ(T_p|T_ref) is the spatial angle between the T peak vector and the normal T reference vector. In the ARIC study in CVD-free middle-aged men and women, the spatial angle between the mean QRS and Tvectors, [Ѳ(R_m|T_m)] was the strongest independent predictor of CHD death with over twofold increased risk in women and 1.4-fold increased risk in men. Ѳ(T_p|T_ref) was also an independent predictor of CHD death, with 1.7-fold increased risk. TV1amplitude was an additional independent predictor in women with a twofold increased risk and TaVR amplitude and the rate-adjusted QT interval were additional independent predictors in men, with an approximately 50 % increased risk.

Ѳ(T_p|T_ref) angle was consistently a strong independent predictor for CHD death. This spatial angle is a measure of deviant direction of the spatial repolarization sequence from the direction of normal repolarization approximately in the direction of the axis of lead aVR. Widened Ѳ(T_p|T_ref) angle commonly occurs with anterior-right rotation of the Tp vector. TaVR and also TV1 can thus be expected to be sensitive indicators of deviant direction of repolarization. TaVR is functionally dependent on Ѳ(T_p|T_ref) angle and both can be considered as primary alternative choices as independent predictors of CHD death. The simplicity of aVR makes it a particularly attractive choice in practical clinical applications.