Acute procedural outcomes of left bundle branch area pacing compared to His-bundle pacing

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Conduction system pacing (CSP), encompassing left bundle branch area pacing (LBBAP) and His-bundle pacing (HBP), is a novel pacing strategy, which overcomes limitations of conventional right ventricular pacing. Feasibility and early safety of both strategies have been established previously. While HBP is mentioned as an alternative pacing strategy in the latest European and American pacing guidelines, implantation recommendations regarding LBBAP are scarce. Notably, HBP was described to be associated with a significantly higher procedural failure rate compared to LBBAP, making it potentially more contestable. PURPOSE: To compare procedural outcomes after HBP and LBBAP lead implantation. METHODS: We prospectively assessed 303 consecutive CSP lead implantation attempts at our center from 08/2018 to 11/2022. 81% of all implantations were performed by two high-volume device implanters. Successful conduction system pacing was established according to standard criteria (HBP: QRS morphology, R-wave peak time in V6, programmed stimulation, visibility of a His potential; LBBAP: R-wave peak time in V6, V1-V6-interpeak interval, programmed stimulation or visibility of a left bundle potential) and pacing thresholds (HBP: <4.0V/1.0ms; LBBAP: <2V/0.5ms). Patient selection and the implantation strategy used was at the operator’s discretion. RESULTS: Patients with a HBP attempt were younger and had a narrower QRS complex but did not differ with respect to left or right ventricular function and dimension (table showing percentages and median values/interquartile ranges). LBBAP systems were more often implanted in lieu of CRT, whereas HBP systems were more commonly used in case of AV block without heart failure (table). Acute procedural success rate, overall procedure duration and fluoroscopy time were significantly better during LBBAP implantations (all p<0.001). Success rates, sensing values and capture thresholds (@1ms for HBP and @0.5ms for LBBAP) were superior in LBBAP systems, while achieved paced QRS duration was slightly shorter in HBP systems (table, figure 1). CONCLUSION: Success rates and acute procedural outcomes favor implantation of LBBAP compared to HBP systems. [Figure: see text] [Figure: see text]