Background: Cardiac resynchronization therapy (CRT) with MultiPoint Pacing (MPP) can improve electrical resynchronization of the left ventricle (LV) compared to conventional CRT. The SyncAV™ algorithm dynamically combines intrinsic atrioventricular (AV) conduction with pacing, improving electrical synchrony. The study objectives included assessment of the change in electrical synchrony with SyncAV and MPP, using non-invasive mapping with electrocardiographic imaging (ECGi).
Methods: Patients with LBBB (QRSd ≥150 ms), in sinus rhythm, scheduled for CRT device (MPP enabled CRT P/D, quadripolar LV lead) implantation underwent ECGi acutely. Mapping was done during intrinsic rhythm, nominal AV delay (140/110ms paced/sensed) and optimized SyncAV (individualized SyncAV offset minimizing QRSd) during: biventricular (BiV) and MultiPoint pacing (MPP). BiV activation time (AT) duration and AT dispersion on the LV (LVED=coefficient of variation of AT) were calculated.
Results: ECGi mapping was completed in 10 patients (80% male, mean age 66.4±16 years, 60% ischaemic, LVEF 30±6%, intrinsic QRSd 167±15ms) following SyncAV optimization. Compared to intrinsic conduction (AT: 136.1±15.8ms, LVED: 22.4±3.6%), AT duration was reduced using BiV SyncAV (104.2±20.4ms, p=0.027), MPP nominal (105.1±17.1ms, p=0.023) and MPP SyncAV (96.7±20.2ms, p=0.001); LVED was reduced only by MPP SyncAV (12.1±4.4ms, p=0.008). With respect to BiV nominal (119.0±31.2ms) MPP SyncAV reduced both AT duration (p=0.049) and LVED (12.1±4.4ms, p=0.049).
Conclusions: The duration and dispersion of LV activation may be reduced incrementally by SyncAV and MPP, whereas the combination of MPP and SyncAV achieved significant improvements in the dyssynchrony of activation.