Left Ventricular and Biventricular Multipoint Pacing With Dynamic Atrioventricular Delays: 6-Month Cardiac Resynchronization Therapy Response.

BACKGROUND: The response to cardiac resynchronization therapy (CRT) can depend on when and where the right and left ventricles (RV, LV) are paced. Dynamic atrioventricular (AV) delays (SyncAV CRT, Abbott) and multi-site LV pacing (e.g., MultiPoint Pacing [MPP], Abbott) are features that may enhance CRT response. Their combined impact has not been evaluated in a chronic clinical setting. OBJECTIVE: Evaluate the 6-month echocardiographic and clinical response to SyncAV when combined with either biventricular MPP (MPP+SyncAV: RV + LV1 + LV2 pacing) or LV-only MPP (LVMPP+SyncAV: LV1 + LV2 pacing). METHODS: CRT-indicated patients with LBBB and intact AV conduction (PR < 250 ms) were implanted and randomized to either MPP+SyncAV or LVMPP+SyncAV in an international, multi-center clinical study. Patient-specific SyncAV offsets were selected to minimize QRS duration at implant. The following response metrics were captured at baseline and 6 months post-implant: LV end-systolic volume (ESV), LV ejection fraction (EF), NYHA class, quality of life score (QoL), and Packer score. RESULTS: CRT implant and 6-month visits were completed in 70 patients (69 years old, 73% male, 179 ms PR, 164 ms QRS). MPP+SyncAV (n = 36) and LVMPP+SyncAV (n = 34) groups demonstrated comparable 6-month response magnitudes and responder rates for ΔESV ≤ -15% (85% vs. 74%) and ΔEF ≥ 5% (94% vs. 77%), as well as improvements in NYHA class (43% vs. 47%), QoL (59% vs. 64%), and Packer score (70% vs. 70%); p > 0.05 for all. CONCLUSIONS: The 6-month echocardiographic (ESV, EF) and clinical (NYHA class, QoL, Packer) response rates observed in LBBB patients were promising when SyncAV was combined with MPP, in both biventricular and LV-only pacing modes. TRIAL REGISTRATION: NCT03567096.