De novo atrial fibrillation and acute myocarditis Fibrilación auricular de novo y miocarditis aguda

Abstract

Introduction:  myocarditis (MCT) is characterized by an inflammatory infiltration into the myocardium associated with degeneration and/or necrosis. Its etiologies include multiple bacteria, toxins, and autoimmune diseases among others. But most commonly it is induced by viruses. Diagnosis is challenging due to its variable presentation, imaging, and laboratory results. Objective: to describe two cases of myocarditis which debuted with atrial fibrillation as an unusual manifestation. Methodology: two cases were registered in Cali, Colombia, with myocarditis diagnosed by contrasted cardiovascular magnetic resonance imaging (cMRI). Cases: the first case corresponds to a 66-year-old female patient with a history of diabetes and hypothyroidism who was admitted for a syncope episode. The second case is a 43-year-old male with chest pain and a negative medical history. Atrial fibrillation (AF) and acute MCT were documented by cMRI. Patients received medical treatment and evolved satisfactorily presenting no cardiac failure at follow-up. Discussion and conclusions: these cases show the heterogeneity of acute MCT clinical manifestations and the importance of suspecting MCT in the presence of de novo AF. Diagnosis may be delayed in our setting due to the lack of access to cMRI, which has become a fundamental tool to distinguish MCT from other life-threatening conditions, such as myocardial ischemia, which also elevate markers such as ultrasensitive troponin.