Myocardial infarction in the young adult. CAD in young male adults below the age of 40 years has generally been found to be associated with the usual risk factors associated with CAD. In a lesser number of young adults, MIs may be related to cocaine use. Sympathomimetic effects and increase in myocardial oxygen demand are factors considered responsible for acute MI in cocaine-abusing patients. In young adults who are asymptomatic following an acute MI and who are able to pass treadmill exercise stress tests at levels of Bruce stage 4 have been shown to have normal coronary arteriograms. Thus this subset should not require routine coronary angiograms following an acute MI. 