Abstract 16355: Prognostic Significance of QRS Fragmentation in the MADIT-CRT
Background: Fragmentation of QRS complex (fQRS) was proposed as an ECG marker of increased mortality in patients with LV systolic dysfunction. The aim of this study was to evaluate the prognostic significance of fQRS for predicting arrhythmic events, heart failure events (HF), and response to resynchronization therapy (CRT) in heart failure patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial — Cardiac Resynchronization Therapy (MADIT-CRT) trial.
Methods: Baseline 12-lead ECGs acquired at enrolment were evaluated for presence of fQRS defined as the presence of >2 notches on the R wave or the S wave present in at least 2 contiguous anterior (V1-V5), lateral (I, aVL, V6) or inferior (II, III, aVF) leads. The end-points were analyzed: 1) arrhythmic events defined as VT, VF or death; 2) VT or VF; 3) death; and 4) lack of echocardiographic response to CRT defined as reduction in LVESV <15% at 1-year follow-up.
Results: There were 1,698 patients with ECG for analysis of fQRS. FQRS were found in 156 (9%) patients, mostly patients with QRS>150 ms (128 of 156 patients) and those with LBBB (126 of 156 patients). In 135 (87%), fQRS was present in anterior leads. Among patients with QRS>150ms, fQRS in any leads were predictive for VT/VF/Death with hazard ratio = 1.66 (p=0.003) and for VT/VF with hazard ratio = 1.68 (p=0.008). In LBBB patients hazard ratio = 1.46 (p=0.031) for predicting VT/VF/death and 1.40 for predicting VT/VF after adjustment for clinical covariates. Figure shows probability of VT/VF/Death in patients with QRS≥150ms. There was no association between fQRS and death, and echocardiographic response to CRT. There were too few patients with QRS fragmentations among non-LBBB patients and among those with QRS≤150ms to determine their predictive value.
Conclusions: FQRS in HF patients with wide QRS complex and/or LBBB morphology is indicative of higher risk of arrhythmic events. There is no association between fQRS and echocardiographic response to CRT.
- Arrhythmias, treatment of
- Heart failure
- Resynchronization therapy
- Bi-ventricular pacing
- Implantable cardioconvert defibrillator
- © 2010 by American Heart Association, Inc.