LAUSR

A 54-year-old female presented with chest pain and was noted to have new T-wave inversion on her electrocardiograph (ECG) in leads V2-V6. The patient has a past history of recurrent DVT/PE and recently had a subtotal colectomy for ulcerative colitis. Serial troponin I measurements were normal (<0.040 μg/l). Transthoracic echocardiogram revealed an impaired left ventricular ejection fraction of 35-40% with hypokinesis within the lateral and apical segments. A coronary angiogram was performed and the left main coronary artery (LMCA) could not be located despite cuspal injections, ascending aortogram and left ventriculogram. A large, dominant right coronary artery (RCA) was visualised which passed around the left ventricular apex to the area normally supplied by the obtuse marginal (OM), diagonal and distal left anterior descending (LAD) arteries. Computed tomography coronary angiography (CTCA) revealed a superdominant RCA supplying the LV apex and lateral wall with no LMCA coming off the left coronary cusp. The left circumflex (LCx) was small and arose from a conus branch with a separate origin to the RCA. No significant stenosis was visualised on CTCA. The T-wave changes were deemed to be secondary to physiological stress/supply-demand ischaemia particularly at the distal end of the RCA, where it supplied the LAD. The patient was commenced on metoprolol 25mg b.d. and continued warfarin on discharge.