Non-ST elevation myocardial infarction, non-obstructive coronary arteries and severe regional microvascular dysfunction in a patient with dilated cardiomyopathy.

Cardiac magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) is a key modality in providing localisation and characterisation of myocardial injury in patients diagnosed with myocardial infarction with non-obstructive coronary arteries (MINOCA). We present a case that demonstrates the unique ability of CMR to provide crucial information in instances of uncertainty. A 71-year-old patient with dilated cardiomyopathy (DCM) presented with symptoms suggestive of acute myocardial infarction. The diagnosis of MINOCA was confirmed following coronary angiography. CMR imaging with LGE confirmed presence of apical infarction. Quantitative myocardial perfusion mapping demonstrated severely reduced blood flow in the non-infarcted septal segments proximal to the distal infarcted territory. The precise aetiology of apical infarction remains uncertain and is likely attributed to coronary plaque rupture. However, concomitant severe regional microvascular dysfunction is also appreciated. This is a recognised, but not well described, phenomenon in DCM and may contribute to repetitive ischaemic injury and disease progression.