A 48-year-old male patient was presented with atypical chest pain and dyspnea. Coronary CT angiography showed a diffuse chronic total occlusion of the left anterior descending coronary artery, a severe stenosis (80–90%) of proximal to mid-left circumflex arteries, and near-total occlusion of the mid-right coronary artery (Figure 1A-C). Echocardiography showed severe left ventricular dysfunction with an ejection fraction of approximately 20%. Emergent percutaneous coronary intervention (PCI) after application of extracorporeal membrane oxygenation (ECMO) was successfully performed (Figure 1D-G). ECMO was weaned after the 3rd day from the index procedure. However, although follow-up echocardiography after PCI showed much improvement in ejection fraction from 20% to 45%, his blood pressure could not be maintained for 6 days without the use of inotropes. His blood pressure dropped severely whenever the dosage of inotropes was reduced and it was impossible to reduce the dosage of inotropes. The level of his serum free cortisol in the morning was 10.18 µg/dL. The interpretation of this test result was that a state of adrenal insufficiency could have occurred considering the critical illness. After administration of steroid, inotropes could be discontinued (Figure 2).