Identifying predictors and cutoff values for pacemaker implantation in ATTR patients

Introduction Cardiac amyloidosis (CA) is recognized as an intrinsic cause of bradycardia, yet current evidence does not suggest different pacing indications for CA patients compared to the general population. Identifying red flags for pacemaker (PM) implantation could help prioritize patients who require closer monitoring Purpose This study aimed to identify patterns and key predictors for PM implantation in ATTR patients, and to establish cutoff values for determining future need for pacing. Methods This study included consecutive ATTR patients diagnosed at a single referral center between 2016 and 2023. A detailed analysis of clinical, laboratory, and echocardiographic data was conducted. The primary outcome was the requirement for pacemaker implantation during follow-up. Patients with PM (n = 54) at ATTR diagnosis were excluded. Results The study cohort consisted of 269 patients, with a median age of 83 years, and 84.4% were male. The median time to PM implantation was 6 months [1.75;11.25].During a fixed 24-month follow-up, 50 patients (18.6%) underwent PM implantation. Indications for pacemaker implantation included complete atrioventricular (AV) block (13 patients, 26%), advanced conduction disturbances (13 patients, 26%), CRT-P (8 patients, 16%), symptomatic atrial fibrillation (AF) with low heart rate (16%), and AF unresponsive to rhythm and rate control (16%). Risk factors associated with PM implantation included a history of AF, QRS >128 ms, left atrial volume index (LAVI) >50 ml/m², interventricular septum (IVS) thickness >18 mm, NT-proBNP >2200 pg/ml, and E/e’ >11. Multivariate regression analysis revealed that QRS duration >128 ms (HR 2.669, 95% CI 1.487–4.792, p < 0.001), IVS thickness >18 mm (HR 2.744, 95% CI 1.533–4.911), and E/e’ >11 (HR 4.298, 95% CI 1.029–17.942) were the strongest independent predictors of future PM implantation. Conclusion In our cohort of ATTR patients, 18.6% required pacemaker within two years after diagnosis. QRS >128 ms, IVS >18 mm, and E/e’ >11 were identified as significant predictors of future pacemaker implantation, providing potential clinical markers for identifying patients at high risk for pacing needs..