Predicting ventricular arrhythmias in patients with ischemic heart disease: clinical application of the ECG-derived QRS-T angle.
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.


RESULTS
ICD patients (n=412, 361 men; age, 63+/-11 years) with ischemic heart disease and a left ventricular ejection fraction < or = 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 < or = 90 degrees (n=124, 30%) with patients with a planar QRS-T angle >90 degrees before device implantation. Furthermore, patients with a spatial QRS-T angle < or = 100 degrees (n=56, 14%) were compared with patients with a spatial QRS-T angle >100 degrees , before implantation. For patients with a planar QRS-T angle >90 degrees as compared with < or = 90 degrees , 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 degrees was associated with an adjusted hazard ratio of 7.3 (95% CI, 1.0 to 53.8). Furthermore, a spatial QRS-T angle < or = 100 degrees 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 < or = 100 degrees might be of value in the identification of patients in whom, although currently indicated, ICD treatment should be reconsidered.
Department of Cardiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
C Jan Willem
CJ
Borleffs
Roderick W C
RW
Scherptong
Sum-Che
SC
Man
Guido H
GH
van Welsenes
Jeroen J
JJ
Bax
Lieselot
L
van Erven
Cees A
CA
Swenne
Martin J
MJ
Schalij
D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000401:mortality / Q000503:physiopathology* / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications*; D011237:Predictive Value of Tests; D011322:Primary Prevention; D016016:Proportional Hazards Models; D016019:Survival Analysis