Multipoint pacing by a left ventricular quadripolar lead improves the acute hemodynamic response to CRT compared with conventional biventricular pacing at any site.

Abstract

Response to cardiac resynchronization therapy (CRT) remains challenging. Pacing from multiple sites of the left ventricle (LV) has shown promising results. The purpose of this study was to systematically compare the acute hemodynamic effects of multipoint pacing (MPP) by means of a quadripolar lead with conventional biventricular (BiV) pacing. Twenty-nine patients (23 men; mean age 72 ± 12 years; LV ejection fraction 29% ± 7%; 15 with ischemic cardiomyopathy, 17 with left bundle branch block; mean QRS 183 ± 23 ms) underwent CRT implantation. Per patient, 3.2 ± 1.2 different veins and 6.3 ± 2.4 pacing sites were tested. LV electrical delay (Q-LV) was measured at each location, along with the increase in LV dP/dtmax (maximum rate of rise of LV pressure) obtained by BiV and MPP. The effect of MPP, by means of simultaneous pacing from distal and proximal dipoles, was investigated at all available sites. Overall, 3.2 ± 1.2 different MPP measurements were collected per patient. When all sites were considered, LV dP/dtmax increased from 951 ± 193 mm Hg/s at baseline to 1144 ± 255 and 1178 ± 259 mm Hg/s on BiV and MPP, respectively. When the best site was considered, LV dP/dtmax increased from a baseline value of 942 ± 202 mm Hg/s to 1200 ± 267 mm Hg/s (BiV) and 1231 ± 267 mm Hg/s (MPP). The mean QRS duration at any site during MPP and conventional CRT was 171 ± 18 and 175 ± 16 ms (P = .003), respectively. Compared with BiV pacing at any LV site, MPP yielded a small but consistent increase in hemodynamic response. A correlation between the increase in hemodynamics and Q-LV on MPP was observed for all measurements, including those taken at the best and worst sites. The MPP-induced improvement in contractility was associated with significantly greater narrowing of the QRS complex than conventional BiV pacing.