P329Optimal site selection during biventircualar endocardial pacing improves acute haemodynamic response and chronic remodeling: A multi-centre UK study

Abstract

Background: Biventricular endocardial (BIV ENDO) pacing may offer a potential benefit over standard CRT, especially in non-responders however the optimal left ventricular endocardial (LV ENDO) pacing site displays large inter and intra-patient variability. Indescriminatly delivered biventricular endocardial pacing (BiV ENDO) is associated with a response rate of between 40-60%, when defined by hard end-points of LV volumetric remodelling. Purpose: We hypothesised that GUIDE (Guidance Using Information to Deploy the Electrode) implants, where the optimal LV ENDO pacing location was identified and targeted during implantation, would improve both acute haemodynamic response (AHR) and chronic markers of CRT response, defined as a significant change in LV end-diastolic volume (LVEDV) and/or LV end-systolic volume (LVESV), Methods: Registry of centres implanting a wireless, left ventricular endocardial pacing system (WiSE-CRT System, EBR Systems, Sunnyvale, California). Each centre used a subtly different GUIDE approach to identify the optimal site John Radcliffe Hospital (Oxford, UK) used electrical latency, Guy's and St Thomas' Hospital (London, UK) used Cardiac Magnetic Resonance and electro-anatomical mapping & The James Cook University Hospital (Middlesbrough, UK) used an echocardiographic guided approach. Results: A total of 18 patients across the three centres underwent a GUIDE implant and had a complete data set at follow up. Patients were predominantly male with a mean age of 68.8 6 8.7 years, mean LVEF was 34.6 6 8.3% & mean QRS duration was 159.26 24.8ms. 22.2% had an ischaemic aetiology. A significant improvement in the mean LV-dP/dtmax was observed when BiV ENDO pacing was delivered at the target site (baseline 876.8 6 196.8 mmHg/s vs optimal site 1013.7 6 241.4 mmHg/s, p <0.01) yielding a mean improvement in AHR of 15.6%. At six months, 77% of patients were classified as BiV ENDO CRT responders, having achieved a significant reduction in their LVESV. Conclusions: GUIDE implants were associated with significant imporvements in AHR and greater improvements in LV cavity reverse remodeling than have been previously achieved using indiscriminate BiV ENDO pacing.