• Subject must be at least 19 years of age

• Acute ST-segment elevation myocardial infarction (STEMI)

• \*STEMI: ST-segment elevation ≥0.1 mV in ≥2 contiguous leads or documented newly developed left bundle-branch block

• Acute non-ST-segment elevation myocardial infarction (NSTEMI)

• \*NSTEMI: NSTEMI is defined as a combination of criteria with mandated elevation of a cardiac biomarker, preferably high-sensitive cardiac troponin with at least one value above 99th percentile of the upper reference limit and at least one of the following:

⁃ Symptoms of ischemia.

⁃ New or presumed new significant ST-T wave changes

⁃ Development of pathological Q waves on electrocardiography.

⁃ Imaging evidence of new or presumed new loss of viable myocardium or regional wall motion abnormality.

⁃ Intracoronary thrombus detected on angiography.

• Successful primary percutaneous coronary intervention (PCI) in \< 12 h after the onset of symptoms for STEMI patients (In case of NSTEMI, PCI should be performed within 72 hours of symptom onset)

• Multivessel disease (at least one stenosis of \>50% in a non-IRA ≥2.25 mm by visual estimation)

• Subject is able to verbally confirm understandings of risks, benefits and treatment alternatives of receiving invasive physiologic evaluation and PCI and he/she or his/her legally authorized representative provides written informed consent prior to any study related procedure.