What is the provocative agent used to diagnose vasospasm during angiography for Prinzmetal angina?

• A. Acetylcholine
• B. Ergonovine
• C. Adenosine
• D. Atropine

Answer: (B)

Provocation testing during coronary angiography is used to reveal or confirm vasospastic angina by temporarily triggering a coronary artery spasm in susceptible vessels. Ergonovine is a classic provocative agent for this purpose. It is a potent ergot alkaloid that increases vascular smooth muscle tone by stimulating serotonin (5-HT) receptors and alpha-adrenergic pathways, leading to reproducible coronary vasoconstriction in patients with hyperreactive coronaries. If a spasm occurs, the patient often develops chest pain and ischemic ECG changes, and the spasm typically resolves with nitroglycerin or discontinuation of the agent.

Other options don’t fit as the primary provocative test in this setting. Acetylcholine can provoke vasospasm in some protocols, especially in patients with endothelial dysfunction, but ergonovine is the traditional and widely used agent for inducing coronary spasm during angiography. Adenosine tends to dilate coronary vessels, not provoke spasm, and atropine is an anticholinergic used for different indications.