This is a single-center double blind, placebo controlled study of patients undergoing a cardiac catheterization where the need for a percutaneous coronary intervention (PCI) is anticipated or will be determined during the early diagnostic phase. The study will assess the use of intracoronary nicardipine vs. sterile saline injection in reducing the index measurement of microcirculatory resistance (IMR). Fifty consecutive patients presenting to the Thomas Jefferson University (TJUH) Cardiac Catheterization lab will be randomized in a 1:1 fashion to receive either intracoronary nicardipine or sterile saline injection prior to PCI. IMR values will be assessed pre and post procedure. Data on clinical outcomes and adverse events will be collected by phone at 30 days and 1 year following the procedure.