Abnormal spatial QRS-T angle predicts mortality in patients undergoing dobutamine stress echocardiography for suspected coronary artery disease

Abstract

To investigate the association between (cardiac) mortality and spatial QRS-T angle in patients undergoing dobutamine - atropine stress echocardiography (DSE) for evaluation of known or suspected coronary disease. Between 1990 and 2003, 2347 patients underwent DSE for evaluation of coronary disease at the Erasmus Medical Center. Echocardiographic images were analyzed offline using a 16-segment, 5-point scoring model for regional function. Twelve-lead resting ECGs were analyzed and patients were grouped in three categories according to their spatial QRS-T angle: normal (0-105 degrees), borderline (105-135 degrees), and abnormal (135-180 degrees). Mean age was 61+/-13 years, 66% were male, 32% had hypertension, 26% had hypercholesterolemia, 28% were smokers, and 12% were diabetic. During a mean follow-up of 7+/-3.4 years, 26.5% (623) of the patients died; 15.3% (359) died due to a cardiac cause. Abnormal QRS-T angle (135-180 degrees ) was present in 21% of the patients. Abnormal QRS-T angle was a predictor of cardiac death [hazard ratio: 3.2 (2.6-4.1)] and all-cause mortality [hazard ratio: 2.2 (1.8-2.6)]. After multivariate analysis abnormal and borderline QRS-T angle, peak wall motion score, age, male sex, history of diabetes, history of heart failure, smoking, and hypertension were independent predictors of (cardiac) death. Abnormal QRS-T angle is an independent predictor of (cardiac) death in patients undergoing DSE. Abnormal QRS-T angle should be considered as a risk factor in stable patients evaluated for coronary disease.