643 Results of implantation of active electrodes in the RVOT in CRT and non-CRT patients

Abstract

pseudobipolar (LV tip -right ventricle (RV) ring or RV distal coil) and extended pseudobipolar (LV ring -RV ring or RV distal coil) configurations. In pacemaker devices, we also evaluated: unipolar (LV distal electrode -can) and extended unipolar (LV proximal electrode -can) pacing configurations. For each configuration we tested the LV pacing threshold, the diaphragmatic capture threshold and the pacing impedance. Results: we included 19 consecutive patients with advanced heart failure and left bundle branch block, they were 18 men, mean EF=23,14-8,2%, QRS=176,44-33,2 ms, NYHA=2,84-0,7, 47,4% with ischaemic and 31,6% with dilated cardiomyopathy. Twelve patients received an ICD resynchronization device. All leads are implanted in posterolateral vein. No failures of implant have been observed. Nominal bipolar pacing was not optimal in any patient. In ICD patients, the optimal pacing configuration was pseudobipolar in 9 and extended pseudobipolar in 3. In pacemaker patients, the optimal configuration was unipolar in 3, pseudobipolar in 2 and extended pseudobipolar in 2. The optimal pacing threshold was lower than the nominal bipolar (1,24-0,8 vs 2,34-1,6; p<0,001), reducing this parameter from 0,2 to 3V. One patient presented diaphragmatic stimulation that was resolved changing the left lead to pseudobipolar pacing, achieving safety margin enough between left ventricle and diaphragmatic capture thresholds. Conclusions: new configurations of pacing through left ventricle lead improved implant pacing parameters, avoiding in some cases the need to reposition. Generally, the optimal results were obtained with a pseudobipolar configuration. Background: cardiac resynchronization therapy (CRT) has shown to reverse left ventricular (LV) remodeling in patients with congestive heart failure (CHF), but its relationship with clinical response has not been assessed. The objective of this study was to analyze if patients who improve clinically have greater LV remodeling than those who do not respond (NR). Methods and results: forty-eight consecutive patients with end-stage CHF, left bundle branch block and LV ejection fraction (EF < 35%) treated with CRT were included. Echo-Doppler scans were taken just before and immediately after the implantation of the pacemaker, and at 6 month follow-up. We compared LV diameters, volumes and ejection fraction (EF) (obtained by M mode and Simpson's method). We considered responders those patients who improved by 10% or more in the 6 minutes walking test, did not die or need a heart transplantation during follow-up. Nine out of 48 patients (19%) did not respond to CRT. There were no differences in baseline LV dimensions between responders and NR. At follow-up, LV volumes and diameters decreased significantly in responders, but did not change in NR (graph Background: pacing and sensing parameters have been described in a general pacemaker population, but not in patients who received a pacemaker in the RV outflow tract (OT) for cardiac resynchronisation therapy (CRT). This study describes the ...