High Quality Content by WIKIPEDIA articles! Multifunction CardioGramTM (MCGTM) is an FDA and AMA approved diagnostic tool used to diagnose myocardial ischemia due to Coronary Artery Disease (CAD). MCG records resting ECG data between the Myocardium and intra-cardiac blood flow to accurately detect CAD without the stress, radiation, chemicals and invasiveness of the current modality set.