Abstract 2922: Automated Time-to-Peak Velocity Detection Using Tissue Synchronization Imaging Accurately Identifies Patients with Left Ventricular Dyssynchrony
Background: Current selection criteria for cardiac resynchronization therapy (CRT) are inadequate for predicting a beneficial response to biventricular pacing. Newer echocardiographic modalities such as tissue Doppler imaging (TDI) can identify regions of intra-ventricular dyssynchrony and improve the selection of patients likely to respond to CRT.
Objective: To determine whether automated time-to-peak velocity detection by Tissue Synchronization Imaging (TSI) is accurate in identifying left ventricular dyssynchrony when compared to manual TDI methods.
Methods: Echocardiograms were obtained on 150 patients with cardiomyopathy (ejection fraction 27 ± 10%) undergoing evaluation for CRT. Time-to-peak velocity between aortic valve opening and closure were manually measured on TDI images at the basal and mid myocardial levels in the 2, 3, and 4-chamber views. Markers were placed on identical segments for TSI analysis. The TSI algorithm automatically detects time-to-peak velocity at each marker and calculates quantitative measures of dyssynchrony (EchoPAC PC, GE).
Results: The Yu Index, or standard deviation of time-to-peak velocity between the 12 measured walls was closely correlated between manual and TSI measurements (r = 0.92, p < 0.001). Peak velocity difference between the basal walls (r = 0.83, p < 0.001) and septal-to-lateral delay (r = 0.75, p < 0.001) were less closely correlated. Using a cut-off value for the Yu Index of > 34 ms to define dyssynchrony, there was agreement in 142 of 150 patients (kappa = 0.89).
Conclusion: Automated determination of time-to-peak velocity by TSI is a simple and accurate method for determining left ventricular dyssynchrony.