A 52 year old woman with hypercholesterolaemia and hypertension had a history of typical chest pain on exertion. An exercise treadmill test was performed, and her baseline ECG was unremarkable. She developed chest pain typical of angina at one minute of standard Bruce protocol associated with ST segment elevation in leads II, III, aVF, V1–V6, and T wave alternans (below left). The chest pain and ST segment elevation resolved with sublingual glyceryl trinitrate spray. The patient subsequently underwent coronary arteriography which showed a 99% diameter stenotic narrowing of the mid left anterior descending coronary artery (below right). Balloon angioplasty with stenting was successfully performed without residual stenosis. The patient had no symptoms after the procedure. A repeat exercise test was performed, the results of which were negative without symptoms or ST changes.

T wave alternans is a rare phenomenon. Patients who develop T wave alternans have an increased chance of malignant ventricular arrhythmia and sudden cardiac death.