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

Pulse arrival time variation as a non-invasive marker of acute response to cardiac resynchronization therapy

AIMS

Successful cardiac resynchronization therapy (CRT) shortens the pre-ejection period (PEP) which is prolonged in the left bundle branch block (LBBB). In a combined animal and patient study, we investigated if changes in the pulse arrival time (PAT) could be used to measure acute changes in PEP during CRT implantation and hence be used to evaluate acute CRT response non-invasively and in real time.

METHODS AND RESULTS

In six canines, a pulse transducer was attached to a lower limb and PAT was measured together with left ventricular (LV) pressure by micromanometer at baseline, after induction of LBBB and during biventricular pacing. Time-to-peak LV dP/dt (Td) was used as a surrogate for PEP. In twelve LBBB patients during implantation of CRT, LV and femoral pressures were measured at baseline and during five different pacing configurations. PAT increased from baseline (277 ± 9 ms) to LBBB (313 ± 16 ms, P < 0.05) and shortened with biventricular pacing (290 ± 16 ms, P < 0.05) in animals. There was a strong relationship between changes in PAT and Td in patients (r2 = 0.91). Two patients were classified as non-responders at 6 months follow-up. CRT decreased PAT from 320 ± 41 to 298 ± 39 ms (P < 0.05) in the responders, while PAT increased by 5 and 8 ms in the two non-responders.

CONCLUSION

This proof-of-concept study indicates that PAT can be used as a simple, non-invasive method to assess the acute effects of CRT in real time with the potential to identify long-term response in patients.

Multisite pacing via a quadripolar lead for cardiac resynchronization therapy

Cardiac resynchronization therapy is challenging. Up to 40% of patients are non-responder. Multisite pacing via a quadripolar lead, also called multipoint/multipole pacing (MPP), is a debated alternative. In this review, we summarize evidence in the literature, tips and pitfalls related to MPP programming, and the different algorithms of MPP in different manufacturers.

Benefits of Multisite/Multipoint Pacing to Improve Cardiac Resynchronization Therapy Response

This article provides a general overview of the underlying mechanisms that support pacing from more discrete points and/or a wider vector (multisite and multipoint pacing) to improve left ventricular resynchronization. We performed a critical overview of the current literature and to identify some remaining knowledge gaps to spur further research. It was not our goal to provide a systematic review with a comprehensive bibliography, but rather to focus on selected publications that, in our opinion, have either expertly reviewed a specific aspect of cardiac resynchronization therapy or have been landmark studies in the field.