A rare, life-threatening effort angina and anomalous origin of the left circumflex coronary artery: CT and SPECT findings.

To cite: Carboni GP, Sedati P. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2013009005 DESCRIPTION In July 2012, a 63-year-old man presented with effort angina occurring in a predictable fashion. He worked as a porter and when carrying heavy loads, angina with palpitations and feeling loss of consciousness, suggested prodromal symptoms of syncope owing to arrhythmia. Stress/rest thallium-201 singlephoton emission cardiac tomography (SPECT) revealed inferior and septal wall reversible defects (ischaemia) without ST-depression at peak during a bicycle maximal exercise test. Cardiac CT documented an anomalous origin of the left circumflex coronary artery (ACXCA) arising from the right sinus of Valsalva with an extramural course between the aorta and the left atrium (figure 1). The angina aetiology was mainly caused by the transient coronary flow reduction elicited by the systolic compression of the ACXCA that is produced by the aorta and the left atrium at peak exercise. In addition, the finding of hypoplastic right coronary artery (RCA) and myocardial bridge over the first diagonal branch (D1) contribute to the coronary reserve worsening during stress exercise (figure 2). The patient was treated with slow-release metoprolol, 200 mg was given once daily for 4 months and stress/rest SPECT was repeated. Metoprolol reduced the myocardial oxygen consumption, ACXCA systolic compression and thus provided the release of the exercise-induced ischaemia on SPECT (figure 3). The β-blocker therapy thus protects this patient from myocardial ischaemia, myocardial infarction and sudden death during daily activities. Combined cardiac CT and SPECT were thus crucial techniques in determining mechanisms and proper therapy of this rare and life-threatening effort angina.