Biventricular or conduction system pacing for cardiac resynchronization therapy: a proposed treatment algorithm based on interventricular conduction delays

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Cardiac resynchronization therapy (CRT) is usually performed with biventricular pacing (BiVP), but recently conduction system pacing (CSP) has been proposed as an alternative in case of unsuccessful coronary sinus lead implantation. CSP was performed as His Bundle pacing or Left bundle branch pacing(1). However, further evidence is needed to determine when CSP should be used in lieu of BiVP to improve clinical benefit. PURPOSE: To assess the clinical benefit of a treatment algorithm based on interventricular conduction delays (IVCD) to choose between BiVP or CSP in candidates to CRT(figure1). METHODS: Consecutive patients presenting at our Institution from January 2018 to December 2020 with an indication to CRT were prospectively enrolled in the study group (delays-guided resynchronization group, DRG). IVCD were measured after left ventricle (LV) lead positioning in a lateral or posterior-lateral cardiac vein, when feasible, using endocavitary electrogram(2). Treatment algorithm based on IVCD was used to decide whether to leave LV lead to perform BiVP or pull it out and perform CSP. Outcomes from the DRG group were compared to a historical cohort of CRT patients (resynchronization standard guide group,SRG). The primary endpoint was a composite of cardiovascular mortality, heart failure (HF) hospitalization, or HF event at 1 year after the date of intervention. RESULTS: Study population consisted in 292 patients, of which 160 (54.8%) in the DRG and 132 (45.2%) in the SRG. In the DRG 41 of 160 patients underwent CSP based on treatment algorithm (25.6%). The primary endpoint was significantly reduced in the DRG (35/160, 21.8%) compared to SRG (48/132, 36.4%) (hazard ratio(HR):1.72;95% confidence interval(CI):1.12-2.65;p=0.013)(figure2). CONCLUSION: A treatment algorithm based on IVCD shifted 1 patient every 4 from BiVP to CSP, with consequent reduction in cardiovascular deaths, HF hospitalizations or HF event after implantation. Therefore, its application could be useful to determine whether to perform BiVP or CSP in CRT candidates. [Figure: see text] [Figure: see text]