Multipoint pacing improves peripheral hemodynamic response: Noninvasive assessment using radial artery tonometry

Background: Multipoint left ventricular (LV) pacing (MultiPoint™ Pacing [MPP], Abbott, Sylmar, CA, USA) improves the response rate to cardiac resynchronization therapy (CRT). We evaluated the feasibility of noninvasive radial artery tonometry (RAT) to characterize arterial pressure morphology changes (pre-ejection period [PEP] and ejection duration [ED]) between conventional CRT and MPP pacing interventions. Methods: Patients with a MPP-enabled CRT device (Quadra Assura MP™, Abbott) underwent noninvasive RAT assessment (SphygmoCor CVMS, AtCor Medical Inc., Itasca, IL, USA) at 3–6 months after implantation. A pacing protocol was performed in a randomized order including one optimized conventional biventricular CRT (CONV) configuration using the distal electrode and five MPP configurations. The PEP, ED, and PEP/ED ratio were determined for each intervention from the RAT pressure waveform and electrocardiogram. Results: Pressure waveforms were successfully recorded in 19 patients (89% male, QRS 147 ± 16 ms, 63% ischemic). In 17/19 (89%) patients, at least one MPP intervention resulted in improved PEP, ED, and PEP/ED compared to CONV. The MPP intervention with greatest separation of LV cathodes and minimum intra-LV delay significantly improved PEP (mean PEP –15 ± 33% vs –8 ± 32% [CONV], P = 0.04) and ED (mean ED +8 ± 8% [MPP] vs +4 ± 7% [CONV], P = 0.02), and PEP/ED (–0.07 ± 0.14 [MPP] vs –0.04 ± 0.13 [CONV], P = 0.02) compared with CONV. Conclusions: Noninvasive RAT efficiently characterizes changes in PEP and ED between CONV and MPP interventions. MPP configurations using the widest separation among LV cathodes and minimum intra-LV delay may significantly improve RAT-derived parameters as compared to conventional CRT.