Fragmented QRS as a predictor of in-hospital life-threatening arrhythmic complications in ST-elevation myocardial infarction patients

Abstract

Background: Fragmented QRS (fQRS) complex is an electrocardiographic pattern that reflects the inhomogeneity of ventricular depolarization. The aims of this study were to determine the prognostic significance of fQRS for predicting in-hospital life-threatening arrhythmic complications in ST-elevation myocardial infarction (STEMI) patients, and to identify the most appropriate duration of cardiac rhythm monitoring in STEMI patients with fQRS. Methods: Patients diagnosed with and treated for STEMI at Siriraj Hospital (Bangkok, Thailand) during 2009–2012 were enrolled. Patients were divided according to fQRS status (having or not having fQRS) at hospital admission. The primary outcome was in-hospital life-threatening arrhythmic events, including sustained ventricular tachycardia and ventricular fibrillation. Time to last life-threatening arrhythmic event from hospital admission was recorded. Results: Of the 452 patients that were included, 96 patients (21.2%) had fQRS. There were significantly more life-threatening arrhythmic events in the fQRS group than in the non-fQRS group (22.9% vs. 4.5%, respectively; p < 0.001). Median (IQR) time to last life-threatening arrhythmic event from hospital admission was significantly longer in fQRS than in non-fQRS (6.58 hr [3.08–39.34] vs. 2.59 hr [1.75–5.75], respectively; p = 0.047). Multivariate analysis identified fQRS as an independent predictor of in-hospital life-threatening arrhythmic events (OR: 4.162, 95% CI: 1.669–10.384; p = 0.002). Conclusions: The presence of fQRS complex on admission ECG was found to be an independent predictor of in-hospital life-threatening arrhythmic events in STEMI patients. Since the time to last life-threatening arrhythmic event from admission was longer in fQRS than in non-fQRS, cardiac rhythm monitoring longer than 24–48 hr may be needed in patients with fQRS.