Predicting Ventricular Arrhythmias in Patients With Ischemic Heart Disease

Abstract

Background— In patients with primary prevention implantable cardioverter-defibrillators (ICDs), the incidence of life-threatening ventricular arrhythmias resulting in ICD therapy is relatively low, prompting for better risk stratification. The aim of this study was to assess the value of the QRS-T angle for prediction of ICD therapy and mortality in primary prevention patients with ischemic heart disease. Methods and Results— ICD patients (n=412, 361 men; age, 63�11 years) with ischemic heart disease and a left ventricular ejection fraction ≤40% were included. After device implantation, the occurrence of appropriate ICD therapy and mortality was noted. A survival analysis was performed comparing patients with a planar QRS-T angle ≤90� (n=124, 30%) with patients with a planar QRS-T angle >90� before device implantation. Furthermore, patients with a spatial QRS-T angle ≤100� (n=56, 14%) were compared with patients with a spatial QRS-T angle >100�, before implantation. For patients with a planar QRS-T angle >90� as compared with ≤90�, the adjusted hazard ratio for the occurrence of appropriate device therapy was 2.4 (95% CI, 1.1 to 5.2); a spatial QRS-T angle >100� was associated with an adjusted hazard ratio of 7.3 (95% CI, 1.0 to 53.8). Furthermore, a spatial QRS-T angle ≤100� exhibited a positive predictive value of 98% (95% CI, 95 to 100) for the prediction of an appropriate therapy-free follow-up. Conclusions— A wide QRS-T angle is a strong predictor of appropriate device therapy in primary prevention ICD recipients with ischemic heart disease. Furthermore, a spatial QRS-T angle ≤100� might be of value in the identification of patients in whom, although currently indicated, ICD treatment should be reconsidered.