ST-Elevation Myocardial Infarction by Nitrate Interruption Immediately after an Ergonovine Provocation Test

A 54-year-old female patient visited our outpatient department complaining of chest pain while sleeping. Two months earlier, she had visited the emergency room with chest pain, and at the time, her electrocardiography (ECG) was normal. However, during the current visit, there was a T-wave inversion on V3 to V6 (Fig. 1A). Her echocardiography (TTE) showed mild hypokinesia at the apex. For further evaluation, we performed a coronary angiography (CAG) and ergonovine (ERG) test. The ERG test confirmed diffuse severe narrowing of right coronary artery (RCA) and left anterior descending artery (LAD) (Fig. 2). After the ERG test, intravenous nitroglycerin (NTG) was administered and her blood pressure dropped to 90 mmHg. Subsequently, administration of the NTG fluid was stopped and she complained of chest pain. The ECG showed ST-elevation at several leads (Fig. 1B). After administration of 0.5 mg of sublingual NTG, the ST elevation disappeared and chest pain was relieved. Instead of NTG fluid, nicorandil fluid was continuously infused. Her troponin-I level was increased to 13702 pg/mL at 6 hours after the event. On the 3rd day of hospitalization, the patient was discharged with a prescription of 5 mg of nicorandil and 90 mg of diltiazem twice a day.

FIG. 1
A) E CG s howed T-wave i nversion on V3 to V6. (B) During recurring chest pain, the ECG showed ST-elevation at II, III aVF, V5, and V6.

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FIG. 2
Coronary angiography (CAG) with the ergonovine (ERG) test. ERG test was first conducted on the LAD. Since the LAD spasm was severe and intracoronary nitroglycerin (NTG) was injected right after the LAD-ERG test, the RCA-ERG test could not be performed. (A) Baseline CAG showed diffuse RCA narrowing before the intracoronary NTG injection. (B) After intracoronary NTG injection, the RCA spasm was relieved. (C) After intracoronary ERG injection, the mid-LAD showed a focal spasm. (D) After intracoronary NTG injection, the LAD spasm was relieved. LAD: Left anterior descending coronary artery, RCA: right coronary artery.

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In most hospitals, intracoronary and intravenous NTG are administered at the end of the ERG provocation test. This is done because of the delayed effect of ERG, which causes contraction of the coronary arteries. For severe variant angina patients whose CAG shows a spasm even before the provocation test, as in this case, we recommend that the discontinuation of NTG fluid should be considered very carefully.