Atrial Fibrillation And Worse Outcomes In St-Segment-Elevation Myocardial Infarction Is It All About Infarct Size, Or Do We Need To Look Elsewhere?

Atrial fibrillation (AF) is a common cardiac arrhythmia in patients admitted to a hospital with myocardial infarction (MI). In a large study looking at 106 780 patients, AF prevalence was 22%, with half of AF patients presenting with and half developing AF during their hospitalization for acute MI.1 With the use of implantable cardiac monitoring, AF incidence was as high as 39% at 24 months in post-MI patients with left ventricular systolic dysfunction.2 The relationship between AF and MI is complex and bidirectional, but it is clear that MI patients with AF uniformly have worse outcomes.3,4 Despite the clear association between AF and poor prognosis in MI, the influence of infarct characteristics on this relationship has remained unclear, mostly because prior studies have lacked the ability to directly assess this important question.See Article by Reinstadler et al Cardiac magnetic resonance (CMR) is a noninvasive tool with the ability to provide myocardial tissue characterization. Gadolinium contrast agent has increased extracellular distribution and delayed washout in areas of myocardial infarct or scar, and late gadolinium enhancement CMR imaging has become the gold standard for assessing myocardial infarct size.5 T2-weighted imaging allows visualization of myocardial edema, and in patients with acute MI, these areas of edema represent the amount of myocardium at risk.6 Amount of myocardial salvage is then …