Equilibrium radionuclide angiography compared with tissue doppler imaging for detection of right ventricular dyssynchrony and prediction of acute response to cardiac resynchronization therapy

Objective: The aim of this study was to compare tissue doppler imaging (TDI) and equilibrium radionuclide angiography (ERNA) for detection of right ventricular (RV) dyssynchrony and prediction of the acute response to cardiac resynchronization therapy (CRT). Methods: This study was approved by the local ethics committee of Huai'an First People's Hospital. Patient consent was not provided due to the use of completely anonymous images from which the individual could not be identified in this study. Thirty-three patients with nonischemic dilated cardiomyopathy underwent both TDI and ERNA before and within 48hour after CRT implantation. RV dyssynchrony was measured with TDI using the difference in time to peak systolic velocity between the RV free wall and ventricular septum (RV-T). With ERNA, the standard of RV mean phase angle and RV phase standard deviation (RVmPA% and RVPSD%) were assessed. Results: Moderate positive correlations were observed among baseline RVmPA%, RVPSD% and RV-T (r=0.689 and 0.716, P<.001). Twenty patients (61%) with a reduction of at least 15% in LV end-systolic volume were categorized as acute responders after CRT. Responders showed significant reduction in RVmPA% and RVPSD% after CRT (53.60 +/- 4.15% to 43.95 +/- 6.88% and 14.00 +/- 2.41% to 10.40 +/- 1.67%, P<.05), whereas RV-T remained unchanged (50.10 +/- 10.28ms to 49.25 +/- 13.64ms, NS). Receiver operating characteristic curve showed that the cut-off value of RV-T was 48.5ms, yielding 65% sensitivity and 77% specificity to predict acute respond to CRT. The cut-off value of RVmPA% was 49.5%, yielding 85% sensitivity and 85% specificity and the cut-off value of RVPSD% was 11.5%, yielding 85% sensitivity and 92% specificity. Conclusion: ERNA might be an appropriate alternative to TDI for assessment of RV dyssynchrony. Either RVmPA% or RVPSD% was highly predictive for acute response to CRT.