The role of real time three dimensional echocardiography to guide optimal lead positioning and improve response to cardiac resynchronization therapy: A prospective pilot study

A non-optimal resynchronization lead (RL) position is a possible cause of poor CRT response. The study aims to test the value of real-time-three-dimensional-echocardiography (RT3DE) for individual assessment of LV dyssynchrony and prospective evaluation of CRT response after RL implantation at the pre-determined segment of maximal delay (SMMD) whatever the method of CRT used. Seventeen HF patients were prospectively included in the study. RT3DE data were obtained before and after 1, 3, 6 months of CRT. Time/volume curves and parametric imaging were applied for pre-implant identification of SMMD and for individual assessment of CRT response. Delta-time delay (delta-t) and selective parameters between tmsv of the latest and earliest activated segments were calculated. All patients received CRT according to accessibility of the SMMD. We used bifocal right ventricular pacing (BFRVP) in 5 patients with septal SMMD; biventricular pacing (BVP) in 12 patients with LV SMMD. The RL was successfully implanted at the SMMD or nearest segment in 14 (82.4%) initial responders (5 BFRVP, 9 BVP). Twelve of them were still responders after 6 months. CRT response was comparable in BFRVP and BIVP. A moderate correlation was found between % change of EF and that of SDI (r = −.406), delta-t (−.497). Baseline delta-t showed a stronger correlation with % change of EF (r = −.718∗∗, P = 0.009) than that of SDI (r = −.509, P = 0.091). The use of RT3DE for individual assessment of LV mechanical dyssynchrony and for optimal RL positioning at the pre-identified SMMD can provide more optimum CRT regardless the method of CRT.