Abstract 11574: Persistent or Worsened Mechanical Dyssynchrony After Cardiac Resynchronization Therapy is Associated With Risk for Ventricular Arrhythmias
Background: Cardiac resynchronization therapy (CRT) improves mortality in heart failure (HF) patients with wide QRS. However, effects on ventricular arrhythmias are less clear. We hypothesized that persistence or worsening of mechanical dyssynchrony is associated with ventricular arrhythmias after CRT.
Methods: We studied 198 consecutive class III-IV CRT-D patients with QRS ≥120 ms and ejection fraction ≤35% (age 65±12 years, 53 (27%) female). Ventricular arrhythmias were defined as appropriate ICD therapy including anti tachycardia pacing and shock over 2 years. Mechanical dyssynchrony was defined as speckle tracking radial peak strain from anteroseptum to posterior wall delay ≥ 130ms, measured before CRT and 6 months after CRT. Four dyssynchrony groups were defined as: 1) No Dyssynchrony (<130ms) before or after CRT, 2) Improved Dyssynchrony ≥ 130 ms before CRT improved to < 130 ms after CRT, 3) Persistent Dyssynchrony ≥ 130 ms before and after CRT and 4) Worsened Dyssynchrony < 130 ms before increased to ≥ 130 ms after CRT.
Results: Overall, 140 patients (70%) had mechanical dyssynchrony before CRT. At follow up, 77 patients (30%) had dyssynchrony: 53 with persistent dyssynchrony and 24 with worsened dyssynchrony. Overall, arrhythmic events occurred in 27 patients (14%) over 2 years of follow-up. Ventricular arrhythmias were significantly more frequent in those with persistent or worsened dyssynchrony compared to all the others (23% vs. 7%, p=0.001) and less frequent in those with improved dyssynchrony (Figure). Interestingly, worsened dyssynchrony was a strong predictor of arrhythmic events independently of age, gender and EF (HR 3.2; 95%CI 1.3-7.5, p<0.01).
Conclusions: Persistent or worsened mechanical dyssynchrony after CRT was strongly associated with ventricular arrhythmic events. Mechanical dyssynchrony is a risk factor for ventricular arrhythmias after CRT and is of prognostic importance.
- © 2013 by American Heart Association, Inc.