Coronary artery disease (CAD)- clogged coronary arteries - can cause angina when blood flow is restricted, or heart attack when flow is severely reduced or completely blocked. If CAD is suspected, the most common initial tests to be given are electrocardiograms (EKGs), chest X-rays, blood tests, and "stress tests". If initial tests confirm the presence of heart disease, then additional tests may be performed. These could include coronary angiograms, echocardiograms, PET scans, and myocardial perfusion scans.