Intracardiac Conduction Time as a Predictor of Cardiac Resynchronization Therapy Response: Results of the BIO|SELECT Pilot Study

Abstract Background Quadripolar left ventricular (LV) leads are capable of sensing and pacing the left ventricle from four different electrodes, which may potentially improve patient response to cardiac resynchronization therapy (CRT). Objective We measured three different time intervals: right ventricular (RV)-sensed to LV-sensed during intrinsic rhythm (RVs-LVs), RV‐paced to LV-sensed (RVp-LVs), and LV‐paced to LV-sensed (LVp-LVs, between distal [LV1] and proximal pole on a quadripolar LV lead), and assessed their association with CRT response in terms of LV end-systolic volume (LVESV) and a composite benefit index (CBI) comprising LVESV, LV ejection fraction (LVEF), brain natriuretic peptide (BNP) level, and NYHA class. Methods A CRT-defibrillator system with quadripolar LV lead was implanted in 196 patients (mean age 69 years, mean LVEF 30%, left bundle-branch block [LBBB] 58%). Conduction intervals were measured before hospital discharge. At baseline and 7-month follow-up, echocardiographic and other components of CBI were determined. Results The mean RVs-LV1s, RVp-LV1s, and LVp-LVs delays were 68±38 ms, 132±34 ms, and 99±31 ms, respectively. From baseline to 7 months, LVESV decreased by 17.3±28.6%. The RVs-LV1s interval correlated stronger with CBI (R2=0.12, p Conclusion The RVs-LVs interval during intrinsic rhythm is relevant for CRT success, whereas RVp-LVs and LVp-LVs intervals did not predict CRT response.