Conduction System Pacing in Cardiac Amyloidosis: Current Evidence, Outcomes, and Knowledge Gaps

Conduction System Pacing (CSP) is a physiologic alternative to right ventricular pacing and may be advantageous in Cardiac Amyloidosis (CA), where conduction disease and septal infiltration are common.

A systematic review of 9 published studies, including 7 case reports or small series and 2 retrospective cohorts, identified 59 patients with CA who underwent CSP.

Left bundle branch area pacing was the predominant technique. Implant success was high overall, ranging between 80 and 95%, with acute capture thresholds between 0.5 and 1.0 V at 0.5 ms and stable performance during follow-up. Paced QRS duration was typically 120-140 ms, representing QRS narrowing in most patients. In individual cases, improvement in New York Heart Association class, natriuretic peptide levels, and left ventricular ejection fraction was observed; however, cohort data demonstrated stable systolic function (45.5% to 41.9%) and unchanged NT-proBNP concentrations. Heart failure hospitalization occurred in 17-35% of patients, and mortality was limited to disease progression in AL amyloidosis. No device-related complications were reported.

CSP in cardiac amyloidosis appears technically feasible and electrically stable in CA and may mitigate the deleterious effects of chronic right ventricular pacing. However, reproducible and longitudinal clinical benefit has not been demonstrated.

Conduction system pacing in cardiac amyloidosis is feasible with favourable electrical parameters, but its clinical utility remains uncertain. Larger prospective registries are required to define its role relative to conventional biventricular pacing.