Among patients with ischemic heart disease who are referred for coronary angiography, a substantial proportion have non-obstructive coronary artery disease (CAD). Myocardial infarction (MI) with non-obstructive coronary artery disease (MINOCA) accounts for 5-20% of patients with MI and preferentially affects women. MINOCA pathogenesis is varied and may include atherosclerotic plaque rupture, plaque erosion with thrombosis, vasospasm, embolization, dissection or a combination of mechanisms. Other patients may have clinically unrecognized myocarditis, or takotsubo syndrome masquerading as MI. Among patients referred for coronary angiography for the evaluation of stable ischemic heart disease, non-obstructive CAD is present in up to \~30% of men and \~60% of women. Stable ischemia with non-obstructive coronary arteries (INOCA) may be due to coronary microvascular dysfunction in up to 40% of these patients. Our understanding of mechanisms of MINOCA and INOCA remain incomplete. Coronary inflammation has been hypothesized as a potential mechanism contributing to coronary spasm in MINOCA and microvascular disease in INOCA.