Problem: A patient with a long history of angina pectoris came to the emergency department complaining of increasing anginal pain that he could not relieve with nitroglycerin and rest. The pain occurred again about an hour prior to arrival at the ED and subsequently increased in severity Cardiac catheterization done recently showed some occlusion of the right coronary artery . It was decided to go ahead with a percutaneous transluminal coronary angioplasty (PTCA ), administering a thrombolytic agent to a coronary artery , in the hope of averting what appeared to be an impending myocardial infarction . The procedure was carried out without incident and the infarction was averted, but the patient did have an occlusion of the coronary artery