Tests to Diagnose Heart Disease
Many tests can help to diagnose heart disease. Which tests you have depends on your symptoms, risk factors, and history of heart problems. Tests used to diagnose heart disease include:
- coronary angiogram
- chest X-ray
- computed tomography (CT) scan
- electrocardiogram (ECG or EKG)
- exercise stress test
- event monitor or Holter monitor
- magnetic resonance imaging (MRI)
- magnetic resonance angiography (MRA)
- multigated graft acquisition (MUGA) scan
- positron emission tomography (PET) scan
- radioisotope stress test.
Angiograms are X-ray pictures of blood vessels. A special dye that can be seen on an X-ray is injected into a blood vessel through a thin tube called a catheter. As the dye flows in the blood vessel, a series of X-rays are taken.
Angiograms allow your healthcare provider to check the inside of a blood vessel to see if it is narrowed, leaking, or blocked. There are many kinds of angiograms to examine different kinds of blood vessels. Angiograms generally look at arteries. For example:
- A carotid angiogram examines the carotid arteries. These arteries travel up each side of the neck and carry blood to the brain.
- A cerebral angiogram shows the blood vessels in the head.
- A coronary angiogram looks at the arteries that bring blood to the heart muscle.
X-rays are a form of electromagnetic energy, or radiation. X-rays are able to penetrate body tissues. They are used to create pictures of body structures on film. An X-ray of your chest can show, for example:
- if the heart is enlarged or normal
- fluid in the lungs.
Computed tomography (CT) scan
Cardiac electron-beam computed tomography is a computer-assisted X-ray scan of the heart. It is also called ultra-fast CT. It can be used to check for coronary artery disease. CT can also check the heart in other ways, including looking at heart valves and the size and function of the lower chambers of the heart. CT can help healthcare providers check nearby blood vessels, such as the aorta, which carries blood from the heart.
After you are positioned in an X-ray scanner, a series of X-ray pictures are taken quickly. The whole test is painless and takes only a few minutes.
An echocardiogram makes pictures of the structure of the heart and its valves by bouncing high-frequency (ultrasound) waves off the heart. The echoes of the sound waves, translated by a computer and recorded on a videotape or computer disk, provide a picture of your heart as it beats. The heart valves, heart chambers, blood vessels, and heart muscle itself can be carefully measured and examined. Ultrasound pictures of the heart are better than X-rays for outlining details of the heart. A special part of the echocardiogram called the color Doppler signal shows blood flow through your heart.
There are 2 types of echocardiograms:
- Transthoracic. In this type of echocardiogram, the sound waves are produced by a transducer placed on your chest.
- Transesophageal. For this type of echocardiogram, you swallow a transducer, or probe. The transducer is carefully placed in your esophagus, which is behind your heart. (The esophagus is the tube that carries food from the throat to the stomach.) Because the probe is much nearer your heart when it is inside you instead of outside and on your chest, the pictures of the heart structures are much clearer.
An electrocardiogram (ECG or EKG) is a recording of the electrical activity of the heart. (Each heartbeat starts with an electrical impulse that causes the heart to squeeze.) For this test small, sticky patches or suction cups are placed on your chest, wrists, and ankles. These electrode patches are connected to a machine that records the electrical activity of your heart. The recording is printed on paper for your healthcare provider to interpret.
Exercise stress test
Many people with narrowing of the coronary arteries have symptoms only when they are physically active. The heart works harder during exercise and needs more blood than when you are resting. If the supply of blood to the heart cannot keep up with the amount of blood the heart needs, there will be changes in the EKG. Recording the EKG before, during, and after exercise shows these changes. The exercise test helps check for narrowing in your arteries.
You will be asked not to eat for about 2 hours before the test. Small sticky patches or suction cups are placed on your back and chest for the EKG. Your blood pressure and an EKG are recorded while you are resting. You then start a slow walk on a treadmill or peddle a stationary bicycle. The treadmill or bicycle will make you have to walk faster or peddle harder every couple of minutes. The EKG and blood pressure continue to be recorded while you exercise and just after the test.
Event monitor and Holter monitor (ambulatory electrocardiogram)
Ambulatory electrocardiographic monitoring (AEM) is a way to record a continuous EKG for up to several weeks. It is mostly used to observe and record your heart rhythm.
Event monitors come in many shapes. They are small devices that you keep with you. When you have pain or other symptoms, you push a button and the monitor stores a record of your heart rhythm at that time. You may then transmit the recordings to your healthcare provider over the telephone. You may be asked to use the recorder for a month or longer.
Holter monitors record the electrical activity of your heart on a tape cassette or digital memory device. Several sticky patches are placed on your chest. Small plastic wires are snapped on to these patches and connected to a monitor. You will keep this device on for 24 to 48 hours.
With both kinds of monitors you will also need to keep a diary of your symptoms and activities.
Magnetic resonance imaging (MRI)
Magnetic resonance imaging (MRI) produces pictures of the heart and blood vessels. You lie on a special table inside the opening of an MRI unit. Radio waves in a strong magnetic field create the images. The MRI is painless. MRI images are very sharp and detailed. They are used to check the structure and function of the heart.
If you have a pacemaker, permanent pacemaker lead, or implantable cardiac defibrillator (ICD), you should not have an MRI.
Magnetic resonance angiography (MRA)
MR angiography (MRA) is an MRI study of the blood vessels. It uses magnetic resonance technology to detect, diagnose, and aid the treatment of heart disorders, stroke, and blood vessel diseases.
Multigated graft acquisition (MUGA) scan
A MUGA scan shows how well the heart is pumping. It measures the amount of blood that is pumped with each heartbeat, and the flow of blood into the pumping chamber. A MUGA scan also gives information about the size of the pumping chambers of the heart and the strength of the heart muscle. This test is also called a radionuclide ventriculogram (RVG) or a gated blood pool scan.
The scan uses an injection of a radioactive chemical, which temporarily highlights your red blood cells. A camera linked to a computer follows the blood moving through the heart. Information from several hundred heartbeats is collected and analyzed.
Positron emission tomography (PET) scan
A PET scan measures chemical changes that occur before signs of disease can be seen on CT and MRI images.
PET scans use a small amount of a radioactive chemical that is attached to a substance that is used by heart cells. The radioactive substance is injected into a vein. A special camera is then used to take pictures of the heart. The PET scan shows how different parts of the heart use the substance. It can identify decreased blood flow and problems with the heart muscle.
Radioisotope stress test
A radioisotope stress test uses radioactive tracers that allow blood flow patterns to be seen on a camera. These tracers are not harmful to you. This test is done along with an exercise stress test on a treadmill or bicycle. An echocardiogram (ultrasound images of the beating heart) is done just before and just after exercise. Sometimes the stress is provided by medicine instead of by exercise.
If there is good blood flow through the arteries, the pictures will show heart muscle that picks up the tracer. If there is decreased or no blood flow though an artery, the pictures will show heart muscle that is not picking up the tracer.
Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.
HIA File diag3652.htm Release 13/2010