Temporal changes in electrocardiographic frontal QRS-T angle and survival in patients with heart failure.

Abstract

Heart failure (HF) is associated with considerable mortality. The electrocardiographic frontal QRS-T angle is a simple parameter to measure, reflects changes in the direction of the repolarization sequence and predicts outcome in patients with HF. Data regarding temporal changes in the frontal QRS-T angle in patients with HF and its impact on outcome is limited.To evaluate temporal changes in the frontal QRS-T angle and its effect on survival in patients with HF.Baseline and follow-up QRS-T angle were calculated from the frontal QRS and T axis of the 12-lead surface electrocardiogram. Patients were followed for survival.2,929 HF patients were evaluated. Median interval between baseline ECG and follow-up ECG was 895 days, median follow-up time was 1526 days. Overall, the QRS-T angle tended to be stable, with minor changes in the angle over time. The median QRS-T angle change was +3° (IQR -19° to +30°). Overall survival during follow-up was 60%. Cox regression analysis after adjustment for significant predictors demonstrated that the QRS-T angle was an incremental predictor of increased mortality. A widening of the QRS-T angle during follow-up was independently associated with an increase in mortality, evident with an increase of the QRS-T angle difference above 0° (P<0.0001 for the adjusted model).QRS-T angle is relatively stable in patients with HF and is a powerful predictor of outcome. Widening of the QRS-T angle has predictive value and is an ominous sign.