Abstract 13032: Utility of Comprehensive Assessment of Strain Dyssynchrony Index by Speckle Tracking Imaging for Predicting Response to Cardiac Resynchronization Therapy
Background: The longitudinal strain delay index is reportedly a marker of both dyssynchrony and residual myocardial contractility.
Hypothesis: We assessed the hypothesis that our relatively simple version of the strain dyssynchrony index (SDI) can predict response to cardiac resynchronization therapy (CRT), and that combining assessment of radial, circumferential, and longitudinal SDI can further improve the prediction of responders.
Methods: We studied 52 patients who underwent CRT. SDI was calculated as the average difference between peak strain and end-systolic strain from 6-segment for radial and circumferential SDI and 18-segment for longitudinal SDI using two dimensional speckle-tracking method. Conventional dyssynchrony measures were assessed by interventricular mechanical delay, Yu Index, and radial dyssynchrony by speckle-tracking strain. Response was defined as a ≥15% decrease in left ventricular end-systolic volume (LVESV) after 3-month.
Results: 36 patients (69%) were responders. Of the individual parameters, radial SDI ≥ 6.5% was the best predictor of response to CRT with a sensitivity of 81%, specificity of 81% and area under the curve (AUC) of 0.87 (p<0.001). Circumferential SDI ≥ 3.2% and longitudinal SDI ≥ 3.6% were also found to be predictive of response to CRT with AUCs of 0.81 and 0.80 respectively (p<0.001). Moreover, radial, circumferential, and longitudinal SDI at baseline correlated with the reduction of LVESV with CRT (r=0.64, 0.40, and 0.43, p<0.001, <0.005, and <0.005). In addition, all the patients with three positive SDIs showed a CRT response (response rates: 100%). In contrast, patients with either one or no positive SDIs had lower response rates of 42% and 22%, respectively (p<0.005 and <0.001 vs. three positive SDIs).
Conclusions: SDI can successfully predict response to CRT and LV reverse remodeling. Moreover, the combined approach leads to accurate prediction than using individual parameters.
- © 2010 by American Heart Association, Inc.