Multifocal spasm with acetylcholine in Prinzmetal angina

A 60-year-old female was awakened early one morning with extreme chest discomfort radiating to both her arms. She felt weak and light-headed and she fainted when she tried to get up. She regained consciousness quickly without sequelae. Upon arrival at the hospital she was without symptoms. The ECG was normal. Physical examination revealed no abnormalities. During her hospital stay she had two more early morning episodes of chest discomfort with inferior ST-segment elevation and second degree as well as complete AV block (figure 1). She is a cigarette smoker with no other classical risk factors. Coronary angiography in the absence of ischaemia revealed a normal left coronary artery and a mild fixed coronary obstruction in the distal segment of the right coronary artery (RCA). The diagnosis of Prinzmetal angina was made.1She was treated with calcium antagonists and nitrates. She was referred for percutaneous coronary intervention (PCI) of the non-critical obstruction (figure 2A), but we decided to perform a provocative test with selective intracoronary infusions of acetylcholine in incremental doses.2 Infusion of acetylcholine at the third dose level (50 μg) induced diffuse mild vasoconstriction and multifocal hyperreactive vasoconstriction (spasm) in apparently normal coronary segments but not at the site of the alleged culprit lesion (figure 2B). The mild constriction and spasms were promptly resolved by intracoronary nitroglycerin (figure 2C). We refrained from PCI and advised an intensification of the therapy with calcium antagonists, nitrates, aspirin and statins, and avoidance of β-blockade and smoking.

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