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Aims: To determine whether new pacing lead technology can be used to overcome problems with left ventricular (LV) lead placement during cardiac resynchronisation therapy (CRT). To establish whether cardiac magnetic resonance (CMR) data can be used to guide LV lead placement in real-time at CRT implant. To establish the best method of multi-site pacing. Methods: We investigated the incidence of problems with phrenic nerve stimulation (PNS) and high capture thresholds at implant and at 4 and 6 month follow-up periods in 40 patients who underwent CRT with a new quadripolar lead. In 20 patients we used a pressure wire to assess the acute haemodynamic response (AHR) to pacing within different regions of the coronary sinus (CS) to determine whether problems with poor AHR can be overcome with electronic repositioning. In 23 patients we used CMR acquisition, processing, overlay and registration tools to guide LV lead placement in real-time during CRT. In 12 patients we turned on the multi-site function of a quadripolar lead, implanted temporary endocardial and epicardial pacing leads and measured the AHR whilst pacing in multiple different ways. Results: Quadripolar lead technology successfully overcame problems with PNS and high capture thresholds at implant and at follow-up but not poor AHR. A CMR dyssynchrony-guided approach to LV lead placement gave an AHR comparable to the best that can be achieved anywhere and was associated with improved reverse remodelling at 6 months. Endocardial pacing gave the best overall AHR but in different patients different methods of multi-site pacing were best. Conclusions: New lead technology can be used to overcome some LV lead problems but not poor AHR. Real-time CMR dyssynchrony guided CRT may be better than conventional empirical LV lead placement. Endocardial pacing gives excellent overall AHR but different methods of pacing (including multi-site) may be better in individual patients. |
