Abstract
BACKGROUND: Cardiac amyloidosis is more common than previously thought with an incidence of up to 15% in aortic stenosis and heart failure with preserved ejection fraction. Pacemaker need in these patients ranges from 9.5% to 20%; however, its prevalence and clinical relevance in patients with unexplained cardiac conduction defects remain unclear. METHODS: This retrospective, single-center cohort study evaluated 1107 patients who underwent intracardiac device implantation for unexplained cardiac conduction defects between 2015 and 2024. Patients with secondary conduction defects or known cardiomyopathy were excluded. The prognostic value of the T-AMYLO score and associated red flag findings were assessed in relation to the composite primary endpoint: all-cause mortality, non-fatal myocardial infarction, and non-fatal stroke. RESULTS: Over a median of 58 months for follow-up, 460 patients experienced a primary event, including 346 deaths. Higher event rates were observed in older males, those with atrioventricular block, and patients receiving single-lead ventricular devices. T-AMYLO score and the presence of red flag findings, particularly aortic valve disease, AV block, peripheral neuropathy, low voltages and increased septal thickness were significantly associated with adverse outcomes. Multivariate Cox regression identified elevated T-AMYLO score (HR: 1.06, p = 0.012), aortic valve disease (HR: 1.29, p = 0.016), and AV block (HR: 1.43, p = 0.009) as independent predictors of mortality. Survival analyses confirmed a stepwise decline in prognosis with an increasing T-AMYLO risk group and red flag burden (p < 0.001). CONCLUSION: These findings highlight the importance of incorporating T-AMYLO scoring and red flags assessment in patients with conduction defects to improve early detection of cardiac amyloidosis and guide risk stratification for outcomes.