The Diagnostic Dilemma of Myocardial Infarction with Unobstructed Coronary Arteries

Cardiovascular magnetic resonance imaging (CMR) is increasingly used in modern cardiology to complement the diagnostic work-up of patients with cardiovascular diseases, and to contribute to risk stratification and patient management. We describe a case of a patient in whom CMR was pivotal in reaching the final diagnosis which carried important implication for patient management and prognosis. A 72-year-old woman presented to the emergency department with intense crushing central chest pain, not radiating to arms/jaw. After clinical assessment, blood tests, echocardiography and angiography, which showed unobstructed coronary arteries, the patient was discharged with a diagnosis of acute myocarditis. She was treated accordingly, and referred for CMR for confirmation of the diagnosis. The CMR revealed myocardial oedema and myocardial scarring. In view of the unobstructed coronary arteries on angiography, this is consistent with a recent myocardial infarction with spontaneous recanalisation. Therefore, the final discharge diagnosis was changed from myocarditis to recent myocardial infarction and the patient’s therapy was modified accordingly (she was started on secondary prevention therapy). This case illustrates the increasing clinical role of CMR in patients with acute coronary syndrome and unobstructed coronary arteries, and its usefulness in reaching the correct diagnosis, which has important implications for clinical management.