Greater Three-Dimensional Ventricular Lead Tip Separation is Associated with Improved Outcome after Cardiac Resynchronization Therapy

Methods: A retrospective study of 86 consecutive patients age 71 +/- 10 years, male (74%), coronary disease (71%), atrial fibrillation (23%), LV ejection fraction (22 +/- 9%), QRS duration (160 +/- 27 ms), New York Heart Association (NYHA) class III (81%), NYHA class IV (19%) undergoing CRT from January 2006 to September 2008. The median follow-up was 12 months and clinical response to CRT was defined as reduction of NYHA class by one or more. The three-dimensional separation between RV and LV pacing lead tips was calculated using measurements obtained from orthogonal posteroanterior and lateral chest radiographs performed the day after implantation. Results: Fifty-nine patients (69%) responded to CRT. There was a statistically significant association between increased three-dimensional lead separation and clinical response to CRT (P = 0.005). Stronger association was obtained when lead separation was corrected for cardiac size (P = 0.001). A significantly higher response rate of 88% was achieved in patients with QRS duration of 160 ms or more, and lead separation of 100 mm or more compared with 60% when lead separation was less than 100 mm and QRS duration remained the same (P = 0.027). Conclusions: Greater three-dimensional separation of LV-to-RV leads is associated with improved response to CRT. A prospective multicenter trial is needed to assess lead separation as a predictor for response. (PACE 2010; 33:1490-1496).