Objective: To determine the effects of interventricular pacing interval and left ventricular (LV) pacing site on ventricular dyssynchrony and function at baseline and during biventricular pacing, using tissue Doppler imaging.
Methods: Using an angioplasty wire to pace the left ventricle, 20 patients with heart failure and left bundle branch block underwent temporary biventricular pacing from lateral (n = 20) and inferior (n = 10) LV sites at five interventricular pacing intervals: +80, +40, synchronous, −40, and −80 ms.
Results: LV ejection fraction (EF) increased (mean (SD) from 18 (8)% to 26 (10)% (p = 0.016) and global mechanical dyssynchrony decreased from 187 (91) ms to 97 (63) ms (p = 0.0004) with synchronous biventricular pacing compared to unpaced baseline. Sequential pacing with LV preactivation produced incremental improvements in EF and global mechanical dyssynchrony (p<0.0001 and p = 0.0026, respectively), primarily as a result of reductions in inter-LV–RV dyssynchrony (p = 0.0001) rather than intra-LV dyssynchrony (NS). Results of biventricular pacing from an inferior or lateral LV site were comparable (for example, synchronous biventricular pacing, global mechanical dyssynchrony: lateral LV site, 97 (63) ms; inferior LV site, 104 (41) ms (NS); EF: lateral LV site, 26 (10)%; inferior LV site, 27 (10)% (NS)). ECG morphology was identical during biventricular pacing through an angioplasty wire and a permanent lead.
Conclusions: Sequential biventricular pacing with LV preactivation most often optimises LV synchrony and EF. An inferior LV site offers a good alternative to a lateral site. Pacing through an angioplasty wire may be useful in assessing the acute effects of pacing.
- biventricular pacing
- lead position
- interventricular pacing interval
- tissue Doppler imaging
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Funding: This work was supported by a research grant from Medtronic Inc.
Competing interests: REL received a research grant from Medtronic Inc and has received sponsorship to attend scientific meetings from Medtronic Inc and Guidant Corporation. AWCC is a consultant on a research grant from Guidant Corporation; he has received sponsorship to attend scientific meetings from Medtronic Inc, Guidant Corporation, and St Jude Medical. JM is a consultant on two research grants from Medtronic Inc and has received sponsorship to attend scientific meetings from Medtronic Inc. DPF has acted as a consultant for Medtronic Inc. NSP has received sponsorship to attend scientific meetings from Medtronic Inc and Guidant Corporation. RJS has received sponsorship to attend medical meetings from St Jude Medical and Guidant Corporation. DWD is a consultant on two research grants from Medtronic Inc; he has received sponsorship to attend scientific meetings from Medtronic Inc and St Jude Medical; he is on the advisory board for St Jude Medical Atrial Fibrillation Division. His partner is an employee of Medtronic Inc.