Incidence and risk factors for pacemaker implantation in light-chain and transthyretin cardiac amyloidosis

Aims The incidence and risk factors of pacemaker (PM) implantation in patients with cardiac amyloidosis (CA) are largely unexplored. We sought to characterize the trends in the incidence of permanent PM and to identify baseline predictors of future PM implantation in light-chain (AL) and transthyretin (ATTR) CA. Methods and results Consecutive patients with AL and ATTR-CA diagnosed at participating centres (2017-2020) were included. Clinical data recorded within +/- 1 month from diagnosis were collected from electronic medical records. The primary study outcome was the need for clinically-indicated PM implantation. Patients with PM (n = 41) and/or permanent defibrillator in situ (n = 13) at CA diagnosis were excluded. The study population consisted of 405 patients: 29.4% AL, 14.6% variant ATTR and 56% wild-type ATTR; 82.5% were male, median age 76 years. During a median follow-up of 33 months (interquartile range 21-46), 36 (8.9%) patients experienced the primary outcome: 10 AL-CA, 2 variant ATTR-CA and 24 wild-type ATTR-CA (p = 0.08 at time-to-event analysis). At multivariable analysis, history of atrial fibrillation (hazard ratio [HR] 3.80, p = 0.002), PR interval (HR 1.013, p = 0.002) and QRS >120 ms (HR 4.7, p = 0.001) on baseline electrocardiogram were independently associated with PM implantation. The absence of these three factors had a negative predictive value of 92% with an area under the curve of 91.8% at 6 months. Conclusion In a large cohort of AL and ATTR-CA patients, 8.9% received a PM within 3 years after diagnosis. History of atrial fibrillation, PR >200 ms and QRS >120 ms predicted future PM implantation.