Clinical introduction An 80-year-old male with a medical history of hypertension, diabetes and moderate calcific aortic stenosis, presented with ischaemic chest pain at rest. Cardiovascular examination revealed soft systolic murmur only. ECG (see online supplementary figure S1) demonstrated inferolateral ST segment depression with ST elevation in lead aVR, suggesting diffuse subendocardial ischaemia possibly consistent with a threatening left main or proximal left anterior descending (LAD) coronary lesion. Emergency coronary angiography demonstrated tandem smooth stenoses in the proximal left circumflex (LCx) and LAD arteries (figure 1A), which persisted throughout the cardiac cycle, and after 200 mcg bolus of intracoronary nitrate. Aortogram is shown (figure 1B).

Question What diagnosis underlies the cause of this patient's symptoms?

1. Congenital coronary artery anomaly.

2. Coronary artery vasospasm.

3. Myocardial bridging.

4. Obstructive coronary artery disease.

5. Unruptured left sinus of Valsalva aneurysm.