Variability of electrocardiographic responses to repeated ergonovine provocation in variant angina patients with coronary artery spasm

We reviewed our experience with serial ergonovine provocative tests for coronary artery spasm (CAS) in ten variant angina patients with angiographically proved CAS. Of the 26 ergonovine tests performed in the ten patients, only four patients exhibited reproducible ECG response to ergonovine. The remaining six patients had variable and unpredictable ECG responses to ergonovine. All patients were in an active phase of their disease. The variability of ST segment directional response to ergonovine is considered to be on the basis of disparate sensitivity of the coronary circulation to intravenous ergonovine. Because of this variable response, the ECG response alone should not be considered as the standard indicator for CAS presence but should be utilized with other hemodynamic and angiographic criteria.