Circumflex masquerade

A 62-year-old man with a history of hypertension, borderline hypercholesterolemia, and unstable angina underwent a cardiac catheterization that revealed a 100% occlusion of the left anterior descending artery with poor distal filling. The left circumflex was an abnormal appearing large vessel, and the distal branch demonstrated a 100% proximal occlusion. The right coronary artery was totally occluded, and the posterior descending artery filled from left to right via collateral flow. The patient experienced several bleeding complications from intravenous heparin and was transferred to our institution for urgent revascularization. Coronary artery bypass graft times four was performed and included reverse saphenous vein graft to the LAD, first diagonal branch, distal left circumflex, and PDA. Approximately 22 months later, the patient began experiencing a burning sensation in the anterior part of the neck after riding a bicycle for 1 mile. Stress Tc-99m MIBI was requested, and the patient stressed via the standard Bruce Protocol. Acquisition was performed in a 180° rotation from 45° RPO to 45° LAO. SPECT images at rest revealed a septal infarct and good perfusion to the remaining myocardium. Given the patient's known situs inversus, the extensive infarction, apparently within the lateral wall, corresponds to the interventricular septum in this complete dextrocardia. For the clinician unaware of this anatomic variant, the LAD territory would be misconstrued as left circumflex pathology.