Fragmented QRS on twelve-lead electrocardiogram predicts arrhythmic events in patients with ischemic and nonischemic cardiomyopathy

BACKGROUND Myocardial scar is a substrate for reentrant ventricular arrhythmias and is associated with poor prognosis. Fragmented QRS (fQRS) on 12-lead ECG represents myocardial conduction delays due to myocardial scar in patients with coronary artery disease (CAD). OBJECTIVE The purpose of this study was to determine whether fQRS is associated with increased ventricular arrhythmic event and mortality in patients with CAD and nonischemic dilated cardiomyopathy (DCM). METHODS Arrhythmic events and mortality were studied in 361 patients (91% male, age 63.3 +/- 11.4 years, mean follow-up 16.6 +/- 10.2 months) with CAD and DCM who received an implantable cardioverter- defibrillator for primary or secondary prophylaxis. fQRS included various RSR= patterns (QRS duration <120 ms), such as >= 1 R prime or notching of the R wave or S wave present on at least two contiguous leads of those representing anterior (V(1)-V(5)), lateral (I, aVL, V(6)), or inferior (II, III, aVF) myocardial segments. RESULTS fQRS was present in 84 (23%) patients (fQRS group) and absent in 100 (28%) patients (non- fQRS group). Wide QRS (wQRS; QRS duration >= 120 ms) was present in 177 (49%) patients. Kaplan-Meier analysis revealed that event-free survival for an arrhythmic event (implantable cardioverter-defibrillator shock or antitachycardia pacing) was significantly lower in the fQRS group than in the non-fQRS and wQRS groups (P <.001 and P <.019, respectively). fQRS was an independent predictor of an arrhythmic event but not of death. CONCLUSION fQRS on 12-lead ECG is a predictor of arrhythmic events in patients with CAD and DCM. fQRS is associated with a significantly decreased time to first arrhythmic event compared with non-fQRS and wQRS.