Abstract Case presentation and management A 81-years old female presented to the emergency department of our hospital with dyspnea and chest pain. She had a history of chronic kidney disease and left bundle brunch block (LBBB) never further investigated. Non diagnostic ECG was performed in the setting of pre-existing LBBB. HS-T-Troponin level was significantly elevated (986 ng/L). A transthoracic echocardiogram (TTE) revealed inferior and posterior wall hypokinesis. NSTEMI was diagnosed and coronary angiography via the femoral artery revealed subocclusive stenosis of the right coronary artery (RCA) and 80% stenosis of left anterior descending artery (LAD). Coronary stent positioning was performed for the RCA culprit lesion and staged complete revascularization was planned. Complications After two days, the patient experienced sharp pain in the right groin and a femoral pseudoaneurysm was diagnosed by Ultrasound Color Doppler. Subsequently anemia suggested the development of retroperitoneal hematoma but it was excluded by contrast CT. Unfortunately, the patient developed acute chest pain, wheezing and erythematous pruritic rash 10 minutes after injection of contrast medium agent. The ECG didn't show any new ischemic abnormalities in the setting of pre-existing LBBB. The peak CK- MB level was significantly elevated (87 ng/mL). New onset apical region akinesia and anterior wall hypokinesia were detected on TTE. Acute coronary syndrome (ACS) was suspected consistent with symptoms, new onset wall motion abnormalities and CK-MB elevations. The patient was diagnosed with allergic reaction and coronary vessel spasm secondary to contrast agent injection in pre-existing atherosclerotic plaque. Due to the high probability of an hypersensitivity reaction to the contrast medium agent we did not perform a new coronary angiography to confirm the diagnosis. Promethazine, Urbason and Nitroglicerin were administered with clinical improvement. The next day we observed recovery of the anterior and apex wall motion abnormalities consistent with coronary vessel spasm. Echocardiographic wall motion abnormalities before and after coronary spasm: Take home message We presented the case of an allergic reaction leading to the release of inflammatory mediators responsible of coronary vessel spasm causing acute myocardial infarction. It can also be induced by injection of contrast medium like in the presented case. Therefore, clinicians and radiologist should recognize this rare but critical disease to ensure prevention and appropriate management.