Stimulation at the optimal LV site yielded significantly higher pump function improvement compared with bifocal LV stimulation (SW β = 12.7 ± 5.1, P=0.012).
Does bifocal LV stimulation improve left ventricular pump function compared to optimal single-LV site stimulation in patients eligible for CRT?
Implantation of a single optimally placed LV lead yields greater acute haemodynamic benefit than a bifocal LV pacing approach in CRT patients.
Effect estimate: β = 12.7 ± 5.1
p-value: p=0.012
AIMS: 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. METHODS AND 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). CONCLUSION: 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.
Roest et al. (Sun,) conducted a other in Eligible for cardiac resynchronization therapy (CRT) (n=33). Stimulation at the optimal LV site vs. Bifocal LV stimulation was evaluated on Left ventricular pump function improvement (stroke work) (β = 12.7 ± 5.1, p=0.012). Stimulation at the optimal LV site yielded significantly higher pump function improvement compared with bifocal LV stimulation (SW β = 12.7 ± 5.1, P=0.012).