Clinical and Epidemiological Profile of Atrial Fibrillation in a High-Altitude Tertiary-Care Setting.

Background and Objectives: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major cause of stroke, heart failure, and death. Evidence on AF in Latin American and Andean tertiary-care settings remains limited. The objective was to describe the demographic and clinical profile, documented thromboembolic and bleeding risk, in-hospital management, and outcomes of adults with AF treated at a tertiary hospital located at 2850 m above sea level. Materials and Methods: We retrospectively reviewed unique adult patient records from January 2021 through December 2023 identified by ICD-10 code I48 and explicit clinician documentation of AF. Independent electrocardiographic adjudication was not performed. Demographics, comorbidities, chart-recorded AF category, risk scores, echocardiographic findings, in-hospital treatments, and outcomes were summarized descriptively. Results: Among 238 patients, mean age was 77.9 ± 13.3 years, 55.0% were male, and 97.1% were recorded as mestizo. Hypertension (58.0%) and heart failure (22.7%) were the most frequent comorbidities. CHA2DS2-VASc and HAS-BLED scores were documented for 199 patients (83.6%); their respective means were 3.3 ± 1.4 and 2.3 ± 1.1. Any anticoagulant was administered during hospitalization to 195 patients (81.9%), but previous and discharge therapy, indications, contraindications, dosing, and temporary interruptions were not consistently available. Five patients died in hospital (2.1%). Secondary exploratory comparisons by survival status were hypothesis-generating, and none remained significant after false-discovery-rate correction. Conclusions: This cohort describes an older, comorbid population treated at a hospital situated at high altitude. The study does not establish an altitude-related AF phenotype, the appropriateness of chronic anticoagulation, or prognostic factors for mortality. Prospective multicentre studies with adjudicated AF, individual altitude exposure, oxygenation and haematologic measures, and longitudinal treatment data are warranted.