Coronary artery vasospasm is an infrequent cause of acute coronary syndrome (ACS). A 50-year-old female developed persistent chest discomfort related to anterior STEMI. After an unsuccessful thrombolysis attempt, due to delay concern, the patient was then sent to the catheterization laboratory for rescue PCI. The coronary angiogram revealed a TIMI 3 flow proximal LAD significant stenosis with spastic appearance of the coronary arteries which has improved after intracoronary nitrates administration. Optical Coherence Tomography (OCT) excluded coronary artery dissection and haematoma also revealed thrombus on moderate atherosclerotic plaque. The patient was then pain-free;she was managed medically and discharged after few days of monitoring. Three weeks later, she developed transient chest pain with ST segment elevation while cycling during rehabilitation program. Provocation test by Ergonovine was positive with complete occlusion of proximal RCA (right coronary artery) complicated by transient complete heart block and shock. She was stabilized with 7 mg of intracoronary nitrates injection. She was discharged after close monitoring with calcium channel blocker and tobacco cessation. ACS may complicate prolonged coronary artery vasospasm making the diagnosis challenging. OCT may help understand ACS mechanism and exclude spontaneous coronary artery dissection. Provocation test is crucial for confirmation.