Bifocal left ventricular stimulation or the optimal left ventricular stimulation site in cardiac resynchronization therapy: a pressure-volume loop study.
OBJECTIVE
Several implantation strategies have been proposed to improve response to cardiac resynchronization therapy (CRT), including bifocal left ventricular (LV) stimulation and optimal single-LV lead placement. This study aimed to compare these two strategies during invasive pressure-volume (PV) loop measurements.


RESULTS
Thirty-three patients eligible for CRT were included [21 (64%) men, 20 (61%) ischaemic aetiology, QRS 155 ± 23 ms], and underwent cardiac magnetic resonance (CMR) imaging and invasive PV loop measurements. Left ventricular pump function was characterized by stroke work (SW) and dP/dtmax (5.1 ± 3.4 L mmHg and 856 ± 190 mmHg/s, respectively). Haemodynamic response was assessed during stimulation at single-LV sites and during bifocal LV [anterolateral and posterolateral (PL)] stimulation. Response during bifocal LV stimulation was not significantly higher compared with standard PL pacing (SW; β = 9.4 ± 5.4, P = 0.080; dP/dtmax, β = 0.2 ± 1.9, P = 0.922). However, mean pump function improvement was significantly higher during stimulation at the optimal LV site compared with bifocal LV stimulation (SW; β = 12.7 ± 5.1, P = 0.012; dP/dtmax, β = 3.3 ± 1.2, P = 0.020). Myocardial tissue properties were assessed by CMR tissue tagging. Mechanical activation at the optimal LV site was significantly more delayed compared with the worst LV site (431 ± 93 ms vs. 326 ± 127 ms; P = 0.004).


CONCLUSIONS
Stimulation at the optimal LV site showed a significantly higher pump function improvement compared with bifocal LV stimulation. Mechanical activation at the optimal LV site was significantly more delayed compared with the non-optimal LV site. In general, these results suggest that implantation of a second LV lead yields no additional benefit over implantation of one optimally placed LV lead. However, a bifocal approach might be beneficial in the individual patient.
Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1118, Amsterdam1081 HV, The Netherlands gj.deroest@vumc.nl.
Gerben Jan
GJ
de Roest
Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1118, Amsterdam1081 HV, The Netherlands.
LiNa
L
Wu
Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1118, Amsterdam1081 HV, The Netherlands.
Carel C
CC
de Cock
Department of Cardiology, Isala Klinieken, Zwolle, The Netherlands.
Peter-Paul H M
PP
Delnoy
Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1118, Amsterdam1081 HV, The Netherlands.
Matthijs L
ML
Hendriks
Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1118, Amsterdam1081 HV, The Netherlands Interuniversity Cardiology Institute of the Netherlands (ICIN), Utrecht, The Netherlands.
Albert C
AC
van Rossum
Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1118, Amsterdam1081 HV, The Netherlands.
Cornelis P
CP
Allaart
D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods*; D002921:Cicatrix / Q000209:etiology; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000628:therapy*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006439:Hemodynamics; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D016277:Ventricular Function, Left / Q000502:physiology; D017725:Ventricular Pressure
Bifocal left stimulation; Cardiac resynchronization therapy; Lead targeting; Pressure–volume loops