Abstract 11337: Acute Reduction In Mechanical Dyssynchrony by Speckle Tracking Strain After Cardiac Resynchronization Therapy is Assocated with Long Term Outcome
Background: Response to cardiac resynchronization therapy (CRT) remains variable. Baseline mechanical dyssynchrony has been associated with left ventricular (LV) reverse remodeling and long term survival, however, the significance of acute mechanical resynchronization is unclear.
Methods: We hypothesized that a significant reduction in degree of dyssynchrony immediately after CRT is associated with acute LV remodeling and favorable long term outcome. We studied 103 consecutive CRT patients: NYHA Class III-IV, ejection fraction (EF) ≤ 35%, and QRS ≥120ms. Echocardiographic examination was performed on all patients prior to CRT and 1±1 day after CRT. EF was calculated using Simpson's biplane method. Radial dyssynchrony was assessed in the mid-LV short axis view. Long term outcome events were pre-specified as death, transplant or left ventricular assist device (LVAD) over 4 years after CRT.
Results: Follow up echo data and dyssynchrony determination was feasible in 85 patients (83%). The study group's age was 66±11 yrs, QRS width 158±24ms, and EF 24±6%. There were 26 events: 22 deaths, 1 transplant, and 3 LVADs over 4 yrs. Using a ROC curve, a 50% reduction in degree of dyssynchrony had a statistically significant reduction in ESV (147±70 to 134±76, p<0.0001) compared with patients without a significant reduction (145±50 to 146±55 ml, p=NS). Importantly, a 50% reduction in degree of radial dyssynchrony was 54% sensitive and 69% specific (AUC= 0.691, p= 0.02) for predicting event-free survival over 4 years after CRT.
Conclusion: An acute reduction in the degree of mechanical dyssynchrony measured by radial speckle tracking appears to be an important marker of response to CRT which is associated with LV reverse remodeling and a favorable long term outcome.
- © 2011 by American Heart Association, Inc.