Optimizing CRT With ECGI

CRT is delivered from two electrodes on opposite sides of the heart \[right (RV) and left ventricle (LV)\] delivering stimulation for more efficient heart beats. There is flexibility in the sequence and temporal staggering of the stimulation from these two electrodes with a different optimum for different patients. However, standard techniques to figure out the optimal stimulation strategy like standard 12-lead surface electrical recording (ECG) or routine ultrasound have failed. The investigators have developed ECG imaging (ECGI) with 250 electrode surface recording combined with CT scan to reconstruct high resolution 4-dimensional panoramic electrical maps of the heart. The study seeks to enroll 56 patients undergoing CRT in a clinical trail to evaluate short and long term impact of using ECGI for optimal programming of CRT.