Coronary Artery Disease (CAD) Diagnosis

Written by the Healthline Editorial Team | Published on August 8, 2014
Medically Reviewed by George Krucik, MD, MBA on August 8, 2014

Diagnosing CAD

Only a doctor can diagnose coronary artery disease (CAD). If you are having symptoms such as chest pain or shortness of breath, you should visit your doctor. Your doctor will perform a routine physical exam, assess your risk factors, and discuss your family health history.

If CAD seems like a possibility, your doctor may order tests or refer you to a cardiologist. A cardiologist specializes in treating heart problems.

There is no one definitive test to diagnose CAD, so you will probably need several.

Tests for CAD can be either invasive or noninvasive. An invasive test requires a device — a catheter, for instance — to be inserted by your doctor into your body via a blood vessel. Noninvasive tests are diagnostic studies that provide information without entering the body’s portals or making an incision. The difference is important. Invasive tests carry a greater risk of complications, such as infection and bleeding.

Invasive Tests

Coronary Angiogram and Cardiac Catheterization

Arteries and veins don’t show up on X-rays unless a special dye is injected into the body to make them visible. This dye, or contrast solution, is injected by means of a catheter. A catheter is a long, flexible tube that is snaked up to the coronary arteries through an incision in the groin, arm, or neck. Arteries narrowed by plaque deposits can be identified easily once the dye has been released.

Coronary Calcium Scan

Plaque is composed, in part, of calcium. Calcium deposits in the arteries — a condition known as calcification is an early indicator of CAD. Calcium shows up well on computed tomography (CT) scans. In order to find calcification in the coronary arteries, a coronary calcium scan is performed. The amount of calcification found in the coronary arteries indicates the degree of atherosclerosis (hardening of the arteries) present. Your score on this test is an indication of the risk that you will have a heart attack within a few years. The results are difficult to interpret and must be considered along with the many other risk factors for CAD. This scan may involve the injection of dye to make your arteries more visible.

Noninvasive Tests


An electrocardiogram (ECG) is a test that measures your heart’s electrical activity. The test records electrical impulses by means of a set of electrodes attached to the chest. The electrical activity is represented graphically by a rhythm strip. An ECG can tell your doctor if you have had a heart attack in the past or if you are having one at present. It can indicate inadequate blood flow to the heart. In some cases, you may be asked to wear a Holter monitor, which is a portable ECG that monitors your heart over a period of time.


An echocardiogram relies on ultrasound technology to create a dynamic picture of heart structure and function, including blood flow. An echocardiogram is sometimes combined with a stress test to see how the heart functions during exertion.

Exercise Stress Test

A stress test reveals how well the coronary arteries deliver oxygen-rich blood to the heart when the heart is put under stress. You may be asked to walk on a treadmill, or stress can be artificially induced with drugs that increase the heart rate. The heart’s performance is tracked using electrocardiography or echocardiography and a blood pressure cuff.

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