Multiple coronary artery fistulae unmasked by myopericarditis

Acoronary artery fistula (CAF) is an abnormal connection between a coronary artery and another structure. This rare condition has an incidence in the general population of 0.002%. A 57-year-old woman presented with angina, a normal electrocardiogram (ECG) and a peak troponin I of 0.22 µg/L (normal <0.04 µg/L). She was treated with a standard medical regimen for non-ST-elevation myocardial infarction. Coronary angiography revealed non-obstructed coronary arteries, with fistulae arising from the left anterior descending, left circumflex and right coronary arteries, all terminating in the pulmonary artery. Cardiac magnetic resonance (CMR) imaging was performed to investigate coronary steal syndrome. This confirmed there was no significant shunt or evidence of infarction. There was a small concentric pericardial effusion with a focal region of inferolateral epicardial fibrosis, suggesting a diagnosis of myopericarditis. The patient was treated with colchicine for three months. CAF can cause patients to present with a variety of symptoms or potentially life-threatening complications, including fistula rupture and myocardial infarction. Early recognition, characterisation and shunt analysis are imperative to facilitate management. Although left/ right heart catheterisation is considered the gold standard, CMR proved to be a useful diagnostic tool in our case, ruling out significant shunting and helping to identify a differential diagnosis.