A 38-year-old female smoker presents with recurrent episodes of chest discomfort at rest, typically between midnight and early morning. During an episode, ECG shows transient ST segment elevation in leads II, III, and aVF that resolves completely with sublingual nitroglycerin. Troponin is undetectable. Coronary angiography shows no fixed obstructive stenosis. What is the most appropriate next step to confirm the diagnosis?
- A Exercise treadmill stress test with echocardiography
- B Coronary spasm provocation test with acetylcholine or ergonovine ✓
- C Fractional flow reserve measurement across all epicardial vessels
- D CT coronary angiography for plaque characterization
Correct answer: B. Coronary spasm provocation test with acetylcholine or ergonovine
Explanation
The presentation is classic vasospastic (Prinzmetal) angina: rest pain with transient ST elevation resolving with nitrates and unobstructed coronaries. When spontaneous spasm is not documented, provocation with intracoronary acetylcholine or ergonovine reproduces focal spasm and confirms the diagnosis. Stress testing detects fixed obstructive disease and would typically be normal here. FFR and CT angiography assess structural stenosis and cannot demonstrate dynamic vasomotor abnormality.
Reference: Braunwald's Heart Disease, 12th ed.
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