Myocardial infarction with non-obstructive coronary arteries (MINOCA) complicating myocarditis

Abstract

Myocarditis can lead to myocardial infarction in the absence of coronary artery obstruction. We report a case of probable myocarditis, complicated by myocardial infarction with non-obstructive coronary arteries. A 19-year-old man presented with chest pain typical of myocarditis. He was a smoker but was otherwise well. Electrocardiogram revealed diffuse ST-elevation and echocardiography revealed a thin, akinetic apex. Troponin-T levels on admission were raised leading to an initial diagnosis of myocarditis being made. However, late gadolinium enhancement study on cardiac magnetic resonance imaging demonstrated transmural enhancement typical of ischaemia. Coronary angiogram was normal, leading to a likely diagnosis of myocardial infarction with non-obstructive coronary arteries. It is important to highlight that coronary assessment remains important when working up for myocarditis, as myocardial infarction with non-obstructive coronary arteries can often complicate myocarditis in cases of normal angiography. Another important lesson was on how cardiac magnetic resonance imaging provided vital evidence to support underlying ischaemia despite normal coronary angiogram, leading to a diagnosis of myocardial infarction with non-obstructive coronary arteries. Myocardial infarction with non-obstructive coronary arteries remains a broad ‘umbrella’ term and cardiac magnetic resonance imaging, as well as more invasive coronary imaging techniques during angiography, can further assist in its diagnosis. Our case provides a reminder that myocardial infarction with non-obstructive coronary arteries, although increasingly recognised, remains under-diagnosed and can often overlap with peri-myocarditis, highlighting the need to employ multi-modality imaging in guiding management.