Published Online
on August 5, 2009

A more recent version of this article appeared on October 1, 2009

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Original Article

Predicting Ventricular Arrhythmias in Patients with Ischemic Heart Disease: Clinical Application of the ECG derived QRS-T Angle

C. Jan Willem Borleffs; Roderick W.C. Scherptong; Sum–Che Man; Guido H. van Welsenes; Jeroen J. Bax; Lieselot van Erven; Cees A. Swenne and Martin J. Schalij¹

Leiden University Medical Center, Leiden, the Netherlands

^* Corresponding author; email: m.j.schalij{at}lumc.nl

Background—In primary prevention implantable cardioverter defibrillator (ICD) patients, 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 (IHD).

Methods and Results—ICD patients (n=412, 361 male, age 63±11 years) with IHD 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%) to 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 to patients with a spatial QRS-T angle > 100º, prior to implant. For patients with a planar QRS-T angle > 90° as compared to 90°, the adjusted hazard ratio for the occurrence of appropriate device therapy was 2.4 (95% CI 1.1-5.2); a spatial QRS-T angle > 100° was associated with an adjusted hazard ratio of 7.3 (95% CI 1.0-53.8). Furthermore, a spatial QRS-T angle 100° exhibited a positive predictive value of 98% (95% CI 95-100%) 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 IHD. Furthermore, a spatial QRS-T angle 100º might be of value in the identification of patients in whom, although currently indicated, ICD treatment should be reconsidered.

Key Words: electrocardiography • tachyarrhythmias • Implantable cardioverter defibrillator • Ischemic heart disease • Primary prevention • ventricular arrhythmia