Abstract 17665: Relationship Between Reverse Remodeling and Resolution of Mechanical Dyssynchrony After Cardiac Resynchronization Therapy: Comparison of Strain Imaging With 3-D Echocardiography, Cardiac Magnetic Resonance, and Speckle Tracking Echocardiography
Background: Imaging for strain and dyssynchrony with cardiac magnetic resonance imaging (CMR) and the circumferential uniformity ratio estimate (CURE) identifies cardiac resynchronization therapy (CRT) responders, but post-CRT imaging with CMR is not routinely performed after CRT defibrillator implantation. Standard echocardiography can evaluate reverse remodeling (change in left ventricular end-systolic volume [LVESV]) after CRT, but 3-D echocardiography (3DE) can also assess changes in dyssynchrony (CURE) resulting from CRT.
Objective: We sought to compare 3DE, CMR, and 2-D speckle tracking echocardiography (STE) for evaluation of the relationship between reverse remodeling and resolution of mechanical dyssynchrony after CRT.
Methods: CMR DENSE (displacement encoding with stimulated echoes) and late gadolinium enhancement (Siemens Avanto), 3DE (GE Vivid E9), and STE were performed in all patients. Echocardiography was repeated at 6 months. CRT response was an improvement in LVESV of 15%. CURE was calculated based on Fourier transformation of regional strain using both CMR and 3DE, and delay in time to peak radial strain in anteroseptal versus posterior walls was determined using STE (STE-delay).
Results: Twenty subjects (66 ± 11 years, 20% female) had 3DE, CMR, and STE. LV ejection fraction (LVEF) was 20 ± 8%, and half had myocardial scar (% scar volume 11.4% ± 4.4%). The CRT response rate was 55% and baseline CURE by CMR was highly predictive of response (AUC =0.94; p < 0.001). 82% of CRT responders had improvement in CURE by 3DE (less dyssynchrony), while all CRT nonresponders had worsening of CURE after CRT (more dyssynchrony). There was a very good correlation between change in CURE by 3DE and percent change in LVESV after CRT (r=0.64; p=0.01). In contrast, there was no significant correlation between changes in STE-delay and LVESV after CRT.
Conclusions: Mechanical dyssynchrony by CURE is highly effective for identification of CRT responders. Most CRT responders had decreases in dyssynchrony by 3DE, while CRT nonresponse was uniformly associated with increased dyssynchrony. Post-CRT assessment with 3DE and CURE for dyssynchrony changes could be very helpful in informing future therapies for both CRT responders and nonresponders.
- © 2013 by American Heart Association, Inc.