Abstract Background Arrhythmias are poorly tolerated by patients with transthyretin cardiac amyloidosis (ATTR). The occurrence rate of pacemaker (PM) implantation among ATTR, along with its predictors and impact on outcomes has not been extensively investigated. Our objective was to analyze the patterns of permanent PM implantation and to identify predictors for future PM placement in ATTR patients. Methods Consecutive patients with wild-type ATTR diagnosed in one single center between 2016-2022 were included. The primary outcome of the study was PM implantation. Patients with pre-existing PM (n = 31) were excluded. The study population included 160 patients, 88% male, median age 82 (76, 85) years. Clinical, laboratory, electrocardiography (ECG) and comprehensive echocardiography data were analysed. Results During a median follow-up of 30.5 months, 37 (23.1%) patients underwent PM implantation. The main indications for PM implantation were complete atrioventricular (AV) block (9 patients, 24.3%) and advanced conduction impairment (9 patients, 24.3%). ECG demonstrated a more prolonged PR interval and increased QRS duration (both p<0.001) with higher rate of first-degree AV block and right bundle branch block (both p=0.003) in patients requiring PM implantation. The echocardiogram showed greater wall thickness, a more dilated left atrium, along with biventricular dysfunction in the PM group. At multivariable analysis, first-degree AV block (HR=2.96, p=0.012), interventricular septum (IVS) thickness (HR=1.27, p=0.001) and biomarker-based staging system (HR= 2.43, p=0.008) were independently associated with PM implantation. PM implantation was associated with increased mortality or HF hospitalization. Conclusions In our cohort of ATTR patients, 23.1% required a pacemaker, primarily due to conduction system disease. Independent predictors for new pacemaker implantation included first-degree AV block, increased IVS thickness, and the biomarker-based staging system.
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