Current guidelines for cardiac resynchronization therapy (CRT) suggest targeting the latest mechanically activated segment for the left ventricular (LV) lead.
To evaluate if selecting the LV target segment by preoperative multimodality imaging can help to increase responder-rate to CRT.
We conducted a prospective double-blinded randomized controlled trial on 102 patients with indication for CRT (27% female, 46% ischemic cardiomyopathy, 63% NYHA class III, 74% left bundle branch block, mean ejection fraction 23%). Optimal LV lead location was defined as the latest mechanically activated available segment (free of transmural scar), determined by radial strain echocardiography, cardiac CT, and magnetic resonance imaging (CMR, n=70). Primary endpoint was reduction of LV end-systolic volume (LVESV) by =15% at six months post-implant. Secondary endpoints were clinical improvement, heart failure (HF) hospitalization and all-cause mortality, and pre-specified on-treatment analysis based on lead location.
Patients were followed for 47 ±21 months. Based on imaging, optimal or adjacent lead placement was feasible in 79% and 96% of cases, respectively. The distribution of optimal, adjacent or distant lead locations did not significantly differ between groups. In 21% of cases (32% in ischemic and 9% in non-ischemic) there was some scar in the designated "optimal" segment, but in only one case was the transmurality >50%. Fifty-six percent of the patients were LVESV responders (56% intervention vs. 55% control, p=0.96), and 71% improved =1 NYHA class (74% vs. 67%, p=0.43), see table 1. In pre-specified on-treatment analysis, patients with distant LV lead placement had higher risk of HF hospitalization (p=0.013), and two-year risk of death or heart failure hospitalization was 17% compared to 3% (p=0.008) for optimal/adjacent lead-location.
Multimodality imaging guided LV lead placement did not result in increased clinical or echocardiographic response. Patients with optimal or adjacent LV lead location had lower 2-year risk of heart failure hospitalization or death, regardless of intervention group.