Real-time three-dimensional echocardiography as a novel approach to assess left ventricular and left atrium reverse remodeling and to predict response to cardiac resynchronization therapy

BACKGROUND Real-time 3-dimensional echocardiography (RT3DE) is a novel promising technique for the assessment of left ventricular (LV) dyssynchrony. OBJECTIVE This study sought to explore the value of RT3DE to assess LV and left atrium (LA) reverse remodeling and to predict response to cardiac resynchronization therapy (CRT). METHODS A total of 57 consecutive heart failure patients scheduled for CRT were included, and RT3DE was performed before and 6 months after implantation. LV dyssynchrony was defined as the standard deviation of the time to reach the minimum systolic volume for 16 LV segments, expressed in percentage of cardiac cycle (systolic dyssynchrony index, SDI). Patients were divided into responders or nonresponders, based on a reduction >= 15% in LV end-systolic volume after CRT. RESULTS Six patients (10%) were excluded from further analysis because of suboptimal images. Of the remaining 51 patients, 34 (67%) were classified as responders. Baseline characteristics were similar between responders and nonresponders, except for the SDI, which was Larger in responders (9.7% +/- 3.6% versus 5.1% +/- 1.8%, P <.0001). ROC curve analysis revealed that a cutoff value for SDI of 6.4% yielded a sensitivity of 88% with a specificity of 85% to predict response to CRT. In responders, RT3DE also showed beneficial effects of CRT on LA: (1) significant LA reverse remodeling; (2) significant improvement in LA total emptying fraction and in LA conduit and reservoir function. CONCLUSION RT3DE allows assessment of changes in LV and LA volumes and function after CRT, and it is highly predictive for response to CRT