How Doctors Diagnose Coronary Heart Disease

Your doctor has a variety of tests to assess your heart health and determine if you need treatment. Find out about options for diagnosing heart problems.

By Marie Suszynski

Medically reviewed by Lindsey Marcellin, MD, MPH

Coronary heart disease is the No. 1 killer of men and women in the United States. Diagnosing and treating it is crucial topreventing a heart attack.

When you have coronary heart disease, the small blood vessels that bring blood and oxygen to your heart muscle become narrow. This is usually because of plaque build-up in artery walls, a condition called atherosclerosis. When the amount of blood getting through these narrowed vessels slows down or stops, it can cause symptoms such as chest pain, fatigue, and breathlessness, and can even cause a heart attack.

Several tests, such as an echocardiogram and angiography, can give your doctor needed information about your heart health and help determine if you have heart disease. What tests your doctor chooses to run will be based on your symptoms and health history.

Testing for Heart Health

Getting your medical history, your family's medical history, and detailed information about your symptoms are key. Along with a physical examination, these are first steps your doctor will take toward making a diagnosis, says Prediman K. Shah, MD, director of the cardiology division at the Cedars-Sinai Heart Institute in Los Angeles.

This information gives your doctor an idea of what may be happening with your heart and guides his or her decision about which of the following tests to order:

• Blood tests. As part of a routine evaluation, your doctor will order blood tests to check for high cholesterol, diabetes, an underactive or overactive thyroid gland, and levels of electrolytes and potassium, which may affect the electrical system of the heart.
• Electrocardiogram (EKG). Doctors often give patients an EKG to get a starting point for a cardiac work-up. An EKG is inexpensive and easy to obtain. It measures the electrical activity of the heart, which can show characteristic patterns associated with heart disease.
  
  "An EKG can tell you whether a patient has an enlarged heart and which part of the heart is enlarged," Shah says. It can also tell your doctor whether the rhythm of your heart is normal or abnormal, and can raise suspicions that someone is currently having a heart attack or has previously had a heart attack.
• Stress test. If your doctor suspects that you have blocked coronary arteries, he may order one of the many forms of a stress test. One example is an exercise stress test, in which you walk on a treadmill or exercise on a stationary bike while your blood pressure and the electrical activity of your heart are measured. "It can unmask hidden obstructions" Shah says.
• Echocardiogram. In addition to other tests, your doctor may order an echocardiogram, which is a noninvasive ultrasound. Although this test is not primarily used to diagnose narrowed or blocked coronary arteries, it can uncover a hole in the heart, leaky heart valves, or signs and symptoms ofcongestive heart failure. It can also tell the doctor if there's fluid around the heart.
• Angiography. If your symptoms are severe, your doctor may decide to go straight to an angiogram to determine the condition of the heart's arteries. This involves threading a catheter through a large blood vessel — usually in the upper thigh area — towards the heart; a dye is then injected into the catheter to outline the coronary arteries. A noninvasive magnetic resonance angiography (MRI) or computed angiography (CT) can also show any narrowing of blood vessels.
• Electron-beam computed tomography. This test looks for calcium deposits in your arteries. Doctors use this test when they suspect plaque build-up (which can contain calcium) in the arteries despite a lack of heart disease symptoms. A doctor may use this test for patients who are at risk for heart disease, but not sure they want to modify their behavior or take medication.
• Nuclear ventriculography. This test uses a radioactive material injected into your vein to show your doctor the chambers of your heart. It is mostly used to measure how well your heart muscle is pumping the blood through your heart.

Fortunately, these tests are widely available in most localities, so your primary care doctor can order many of them to assess your heart health. Sometimes a patient is referred to a cardiologist before testing. Fifty percent of the time, the first sign of a blockage in an artery is a heart attack or sudden death, so it's important to talk to your doctor about your family history, health habits, and any symptoms you're experiencing. Together, you can decide if and when you should be tested for heart disease.