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Original Articles

Predicting Ventricular Arrhythmias in Patients With Ischemic Heart Disease

Clinical Application of the ECG-Derived QRS-T Angle

C. Jan Willem Borleffs, MD; Roderick W.C. Scherptong, MD; Sum-Che Man, MD; Guido H. van Welsenes, MS; Jeroen J. Bax, MD, PhD; Lieselot van Erven, MD, PhD; Cees A. Swenne, PhD and Martin J. Schalij, MD, PhD

From the Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.

Correspondence to Martin J. Schalij, MD, PhD, Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands, PO Box 9600, 2300 RC Leiden, The Netherlands. E-mail m.j.schalij{at}lumc.nl

Received February 23, 2009; accepted July 22, 2009.

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.

Key Words: implantable cardioverter-defibrillator • electrocardiography • ventricular arrhythmia • primary prevention • ischemic heart disease

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CLINICAL PERSPECTIVE

Drs Borleffs and Scherptong share first authorship.