The management of acute myocardial infarction (AMI) 1 has evolved over the past century and particularly in the past 50 years. Important milestones include the development of the electrocardiogram, coronary care units, coronary angiography, reperfusion therapies, and troponin assays. These innovations are the foundation of contemporary AMI management strategies that include a diagnosis centred on elevated troponin values associated with corroborative clinical evidence, 1 early use of coronary angiography, and reperfusion therapies. 2–4

Pivotal in the evolution of these contemporary strategies were the early AMI coronary angiography studies undertaken by DeWood et al. These pioneering studies demonstrated that, in patients presenting with ST elevation myocardial infarction (STEMI), almost 90% had an occluded coronary artery provided that angiography was undertaken within 4 h of chest pain onset. 5 In contrast, in AMI patients who did not present with ST elevation (non-ST elevation myocardial infarction or NSTEMI), only 26% had an occluded coronary artery when angiography was performed within 24 h of symptom onset. 6 In both of these landmark studies, 5, 6. 90% of the acute MI patients had angiographic evidence of obstructive coronary artery disease (CAD), underscoring the importance of the atherosclerotic process in the pathogenesis of AMI. Although DeWood’s studies underscore the importance of obstructive CAD in AMI, it is fascinating that 10% had no significant CAD on coronary angiography. This is confirmed in several large AMI registries 7–9 where 1–13% of AMI’s occurred in the absence