Usefulness of electrocardiographic frontal QRS-T angle to predict increased morbidity and mortality in patients with chronic heart failure.

Abstract

The risk of death in heart failure (HF) is high. The electrocardiographic spatial QRS-T angle reflects changes in the direction of the repolarization sequence and predicts death in the general population. The frontal QRS-T angle is simple to measure but has not been evaluated in a large chronic HF cohort. We examined the significance of the frontal QRS-T angle in predicting the clinical outcome in a large cohort of patients with HF. The QRS-T angle was calculated from the frontal QRS and T axis of the baseline 12-lead surface electrocardiogram. The patients were followed for cardiac-related hospitalizations and death; 5,038 patients with HF were evaluated. The mean follow-up period was 576 days; 51% were men. Overall survival during the follow-up period was 83%. Cox regression analysis after adjustment for significant predictors, including age, gender, ischemic heart disease, hypertension, atrial fibrillation, body mass index, pulse, serum hemoglobin, sodium, estimated glomerular filtration rate, and urea levels, demonstrated that the QRS-T angle was an incremental predictor of increased mortality in both genders. For women, a QRS-T angle of ≥60° had a hazard ratio of 1.35 (95% confidence interval 1.04 to 1.75; p <0.05) and a QRS-T angle of ≥120° had a hazard ratio of 1.45 (95% confidence interval 1.10 to 1.92, p <0.01). For men, a QRS-T angle of ≥130° had a hazard ratio of 1.53 (95% confidence interval 1.14 to 2.06, p <0.01). For the whole cohort, a QRS-T angle of ≥125° gave a hazard ratio of 1.47 (95% confidence interval 1.20 to 1.80, p <0.0001). The QRS-T angle was also a predictor of increased cardiac-related hospitalizations. The QRS-T angle was a predictor in patients with reduced and preserved left ventricular function and in patients with a normal QRS interval. In conclusion, the QRS-T angle was a powerful predictor of outcome in patients with HF. We believe the QRS-T angle should be a part of the electrocardiographic evaluation of patients with HF.