Some risk factors at the time of MI also contribute to the prognosis of recovery. Some of the risk factors that contribute to worse outcome are: age (risk increases with age), sex (men compared to women), family history, previous history of CAD, sedentary lifestyle, obesity, diabetes, cholesterol , alcohol, smoking. Myocardial infarction usually involves the left ventricle of the heart, but can sometimes involve the right ventricle. MI can be classified as subendocardial; a myocardial infarction without Q wave, involving the inner layer of the myocardium, subepicardial, involving the inner and middle layer, and transmural, a myocardial infarction with Q wave depression, involving all 3 layers of the myocardium. We diagnose myocardial infarction based on clinical history, Q wave changes in the ECG, and increases in cardiac marker enzymes, such as troponin and