In patients with cardiac sarcoidosis (CS), left bundle branch area pacing (LBBAP) is feasible and provides stable long-term lead performance, according to a single-center retrospective study published Nov. 21 in JACC: Clinical Electrophysiology. Larger studies are still needed to assess the clinical benefit of LBBAP in the presence of septal inflammation and fibrosis.

Michael Gurin, MD, et al., identified patients with CS who underwent LBBAP at a single tertiary center from January 2020 through March 2024. Echocardiographic data, device parameters and procedural metrics were assessed at baseline and follow-up, and CS was defined using Heart Rhythm Society criteria using histologic or imaging-based evidence. LBBAP was confirmed using criteria from the European Heart Rhythm Association.

Of the 19 patients (mean age, 59 years; 21% female) who met inclusion criteria, atrioventricular block was the most common indication (58%). Additionally, septal involvement was seen in 61% on positron emission tomography and 53% in cardiac magnetic resonance imaging.

LBBAP was successful in all patients without acute complications. Of note, baseline-paced QRS duration was 139 ± 25 ms; mean threshold was 0.75 ± 0.26 V, R-wave amplitude was 15.2 ± 6.3 mV, and impedance was 738 ± 208 Ω. Lead parameters remained stable over a 437-day follow-up, and no differences in pacing parameters were seen based on septal involvement. QRS was >130 ms and LVEF <50% in four patients and LVEF improved from 27% to 50% (p=0.06) among patients with LBB block.

"Integration of advanced imaging into procedural planning allows better patient selection and may optimize long-term outcomes" write Gurin and colleagues. "Further studies are needed to define optimal timing of conduction system pacing in CS and other inflammatory cardiomyopathies."

Edoardo Bressi, BMBS, and Jordana Kron, MD, FACC, emphasize that these findings "highlight the need for an integrated pacing-defibrillation approach in this population" in an accompanying editorial comment. "Ongoing research should focus on long-term outcomes, imaging-guided implantation, and the potential of LBBAP-based systems to provide physiological resynchronization and arrhythmic protection in this challenging patient population."