Atrial fibrillation and associated cardiovascular disorders in adults with hyperthyroidism: a retrospective cohort study from two teaching hospitals.

INTRODUCTION: Atrial fibrillation (AF) is a major cardiovascular complication of thyrotoxicosis but its burden and predictors are poorly described in sub-Saharan Africa. We assessed the prevalence, clinical course, and predictors of AF and related cardiovascular complications in adults with hyperthyroidism at two tertiary hospitals in Addis Ababa, Ethiopia. METHODS: Retrospective cohort study of adults (≥ 18 years) with biochemically confirmed hyperthyroidism managed between April 2019 and September 2024. Clinical, ECG and echocardiographic data were abstracted from records; primary outcomes were AF at presentation and persistent AF on follow-up. Associations were examined with multivariable logistic regression. RESULTS: Of 174 patients (mean age 41.2 ± 11.6 years; 91.9% female), 43 (24.7%) had AF at presentation and 34 (19.5%) remained in persistent AF. Thromboembolic events (echocardiographic contrast n = 2; LV thrombus n = 1; ischemic stroke n = 1) occurred only in persistent AF. Independent predictors of AF included left atrial enlargement (LA ≥ 3.8 cm; AOR 8.6, 95% CI 1.9–38.5), NYHA class III–IV at presentation (AOR 8.9, 95% CI 2.5–33.0), diastolic dysfunction (AOR 5.4, 95% CI 1.4–21.5) and elevated baseline free T3 (AOR 12.5, 95% CI 3.1–50.2). Most patients received propylthiouracil (97.7%) and beta-blockers; anticoagulation was infrequently prescribed (n = 3). Biochemical normalization was slow, and AF was associated with delayed thyroid hormone normalization. CONCLUSION: In this Ethiopian tertiary-care cohort, AF was common and frequently persistent; elevated thyroid hormone levels and atrial structural changes were strong predictors. Early ECG and targeted echocardiography, prompt restoration of euthyroidism, and guideline-directed anticoagulation for high-risk patients are warranted to reduce thromboembolic and heart-failure complications.