QRS duration: a predictor of delivering appropriate shocks in patients with implantable cardioverter defibrillator

Ventricular tachycardia attacks are one of the main causes of cardiac death. Ventricular tachycardia attacks can be treated using implantable cardioverter defibrillator (ICD) and this device prevents death due to Ventricular tachycardia attacks. For optimal use of this treatment method, it is better that individuals initially be selected based on clinical or laboratory criteria. This study aimed to evaluate clinical findings predictive of recurrence of heart attacks in patients undergoing ICD therapy.
Subjects & In this retrospective cohort study, all patients referring to Ghaem Hospital in Mashhad from the beginning of 2005 until the end of September 2008 and underwent ICD for various clinical reasons, were included. Data analysis was conducted using R software. The frailty model was used to investigate the effect of factors, including age, gender, family history, ICD manufacturer, QTC and QRS time on receiving appropriate shocks.
Findings: The mean age of patients was 46/63±15.51 years. A total of 30 patients (69.8%) were male and 38 patients (88.4%) do not have a family history of heart disease. In these patients, the mean and standard deviation of QTC and QRS duration were 467.4± 62.87 ms and 110.063± 31.64 ms, respectively. According to the results of frailty model fitting , QRS was the only variable affecting the appropriate shock. (P= 0.0016)
Patients with longer QRS receive more appropriate shocks that are due to recurrent ventricular tachycardia