The purpose of this study is to determine whether a single intracoronary infusion of an adenovirus serotype 5 virus expressing the gene for human fibroblast growth factor-4 (Ad5FGF-4) is effective in improving angina-limited exercise duration, angina functional class, frequency of angina attacks, frequency of nitroglycerin usage, and quality of life. Half of the study participants will receive Ad5FGF-4, and half will receive placebo. The primary endpoint is the change from baseline to Month 6 in Exercise Tolerance Test (ETT) duration. Long-term safety of Ad5FGF-4 will also be assessed.