Aims: It is time consuming to obtain optimal interventricular (VV) delay by conventional methods. This study is designed to compare quick optimization between intracardiac electrogram (IEGM) with surface electrocardiogram (ECG)-guided VV delay optimization for cardiac resynchronization therapy (CRT).
Methods and results: Fifty-one heart failure patients (M/F = 34/17, age = 71 ± 10-year-old) scheduled for CRT implantation were included. After atrioventricular optimization, VV delay optimization was performed by either the IEGM or surface ECG method. Aortic velocity time integral (AVTI) was used as a reference in comparing these two methods. Real-time three-dimensional echocardiography was studied under three varying parameters-CRT switched off or CRT switched on, and VV delay optimized by IEGM guided or surface ECG. The AVTI could be improved equally by either IEGM-guided or surface ECG-guided VV optimization. All the other parameters [QRS width, systolic dyssynchrony index (SDI), left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV)] could be improved by either the IEGM or ECG method in these patients. In the multivariate logistic regression analysis, the immediate improvement of acute LVEF was independently related to favourable outcomes (odds ratio 1.23, 95% CI = 1.03-1.47, P = 0.02).
Conclusions: The AVTI, QRS width, SDI, LVEF, LVEDV, and LVESV could be improved equally by either IEGM-guided or surface ECG-guided method after CRT.