Embolic Myocardial Infarction as a Consequence of Atrial Fibrillation: A Prevailing Disease of the Future.

Abstract

Acute myocardial infarction (AMI) is a major cause of death and disability worldwide. When spontaneous AMI occurs, there is a >90% chance that the underlying etiology is primarily due to coronary events such as plaque rupture, erosion, or dissection referred to as myocardial infarction (MI) type 1.1 MI can also occur secondary to an ischemic insult in the absence of overt coronary artery disease (CAD), by an imbalance between myocardial oxygen supply and demand termed type 2 MI, which embodies a myriad of diseases (Table). In general, it is estimated that 4% to 7% of all patients diagnosed with AMI, however, do not have CAD at coronary angiography or autopsy.3 View this table: Table. List of Reported Causes of Myocardial Infarction From Coronary Embolism in the Absence of Coronary Atherosclerotic Disease Article see p 241 Another important category that falls within this realm is coronary artery embolism (CE) in which a thrombus arising from sources other than the coronary vasculature propagates into the coronary arteries causing AMI. Previous work on this subject is limited by the small numbers of patients examined, and, given the vast distribution of patients presenting with AMI worldwide, a more systematic approach would greatly improve our understanding of its diverse etiologies, in particular, the role of CE. In this issue of Circulation , Shibata et al4 report on 1776 consecutive cases of new-onset AMI between 2001 and 2013 that were screened for etiology with a focus on CE and a diagnosis based on histological, angiographic, and other diagnostic imaging modalities. Overall, 52 patients were identified with CE, with a prevalence of 2.9%, defined as probable in 20 cases, and definite in 32. The authors implicate atrial fibrillation (AF) as the most common cause of CE, 38 of 52 (73%) patients in comparison with non–AF-related CE, 116 of …