The last 15 years the introduction of primary angioplasty has radically improved outcomes for acute myocardial infarction (AMI). However, the system wide availability of prompt investigation has revealed an important group of patients where progress has stalled, the diagnosis is unclear and therapeutic approaches are uncertain. Myocardial infarction with non-obstructive coronary arteries (MINOCA) is found in 1 - 13% of all patients with a clinical diagnosis of AMI. These patients present a therapeutic predicament since coronary revascularization is not appropriate. Guidelines do not exist for their management - yet the condition is not benign - the 12-month prognosis, although better than obstructive coronary artery disease patients is still guarded with recent data suggesting many questions remain unanswered.