Cardiac resynchronization therapy – A comparison of VV delay optimization by 3D echocardiography using systolic dyssynchrony index and QRS width assessment at 6 months after CRT implantation

Abstract Aim The aim of this study was to compare the setting of interventricular (VV) delay by 3D echocardiography (3DE) using systolic dyssynchrony index (SDI) versus QRS width measurement in new cardiac resynchronization therapy (CRT) recipients. We observed the impact on the reduction of left ventricle volumes and increase in volumetric responders (defined as a ≥15% reduction in left ventricular end-systolic volume (LVESv)) at the 6-month follow-up. Methods We included 63 patients with recently implanted CRT in this open-label, randomized trial. Patients were randomized into two groups. VV delay was set by the QRS width in the group 1 ( n 31) to obtain the narrowest QRS complex and by SDI in the group 2 ( n 32) to achieve the lowest possible value. We evaluated LVESv, left ventricular ejection fraction (LVEF) by 3DE, before CRT implantation and at 6-month follow-up, in all patients. We also obtained clinical parameters and the level of NT-proBNP. Results The second group showed only a trend toward greater reduction of LVESv (−33 ± 55 ml vs. −48 ± 43 ml; P 0.367), increase in LVEF (+7.3 ± 10.9% vs. +10.2 ± 9.4%; P 0.210) and greater number of volumetric responders (14 vs. 18; P 0.612) compared with the group 1 at 6-month follow-up. There were also no significant differences in clinical outcomes and the level of NT-proBNP. Conclusion Individual CRT optimization using SDI compared with QRS duration assessment did not reveal any significant differences in echocardiographic parameters and clinical outcomes at 6-month follow-up.