Interlead anatomic and electrical distance predict outcome in CRT patients

Background The implantation strategy appears to play a pivotal role in determining response to cardiac resynchronization therapy (CRT). Objective The aim of our study was to determine the association between anatomic and electrical interlead distance and clinical outcome after CRT implantation. Methods We included 216 first-time CRT recipients with left bundle branch block and sinus rhythm. On implantation, the electrical interlead distance (EID), defined as the time interval between spontaneous peak R waves detected at the right ventricular (RV) and left ventricular (LV) pacing sites, was measured. The anatomic distance between the RV and LV lead tips was determined on chest radiographs. Results The mean EID was 74 ± 41 ms, and the mean horizontal corrected interlead distance (HCID) was 125 ± 73 mm. After 12 months, 87 patients (40%) displayed an improvement in their clinical composite score. The cutoff values that best predicted an improved clinical status were as follows: 84 ms for EID (area under the curve 0.59; confidence interval [CI] 0.52-0.66; P =.026) and 90 mm for HCID (area under the curve 0.62; CI 0.55-0.69; P =.004). On multivariate analysis, only EID >84 ms (hazard ratio 0.36; CI 0.14-0.89; P =.028) and HCID >90 mm (hazard ratio 0.45; CI 0.23-0.90; P =.025) were significantly associated with the composite endpoint of death or cardiovascular hospitalization. In particular, the presence of both conditions (EID