Resumen:
Background: Interatrial block (IAB) is associated with atrial fibrillation (AF) in different clinical situations, but little information exists in elderly patients with myocardial infarction (MI) and its association with frailty. Methods: Consecutive MI patients aged ≥ 75 years were prospectively included. Frailty was assessed during the admission, as well as the prevalence of IAB. Main outcome measure was mortality and new onset AF at one year. Results: We included 254 patients. From 220 patients with sinus rythm (86.6%), 37 had partial IAB (16.8%) and 34 advanced IAB (15.5%). Patients with advanced IAB had lower values of handgrip strenght (19.8 vs 21.7 kg, p 0.073). These patients had a trend toward higher incidence of AF or mortality during follow up (HR 1.51, 95% CI 0.85–2.70, p = 0.164). Conclusions: Advanced IAB was associated with a trend toward higher prevalence of frailty. Elderly patients with MI and advanced IAB had a trend toward higher incidence of AF.