Patients presenting with ST elevation myocardial infarction

Complete total occlusion of the vessel

Unprotected left main disease

Presentation with acute coronary syndrome and actively rising troponin

Contraindication to adenosine (advanced heart blocks, bronchospasm, HSN to the drug)

Known hypersensitivity to nicardipine

Severe aortic stenosis

Left Ventricular dysfunction with ejection fraction less than 30%

Hemodynamically unstable defined as systolic blood pressure \< 90 mmHg and not responding to IV fluids

Significant chronic renal insufficiency (Glomerular filtration rate \[GFR\] \<30)

Unwilling or unable to provide informed consent

Prevention of Coronary Microvascular Dysfunction Post-PCI by Intracoronary Nicardipine