Radionuclide Ventriculogram

What is a radionuclide ventriculogram?

The radionuclide ventriculogram (RVG) measures the heart's pumping function. It is also called a MUGA (multi-gated acquisition) scan. The RVG is the most accurate test available to measure how well the heart is pumping.

The right ventricle is the chamber of the heart that pumps blood to the lungs. The left ventricle pumps blood to the rest of the body. A measurement that can be made with an RVG is the ejection fraction. The ejection fraction measures the strength of the left ventricle. It is the percentage of blood pumped out of the left ventricle with each heartbeat. A normal ejection fraction is 50% or more. The ejection fraction helps to guide treatment and helps predict your risk for future heart problems. The RVG can also measure the right ventricle's ability to pump blood to the lungs.

When is it done?

The RVG is very accurate. It can detect subtle, early changes in heart function that might easily be missed by other tests.

The RVG is used to check for damage from a heart attack, or to assess your risk of heart disease. It may also be done if:

• You have a serious condition called heart failure. This happens when the heart is not pumping well and there is a buildup of fluid in the lungs. Heart failure may also cause swelling (edema) in the legs.
• You have dilated cardiomyopathy, which means your heart's ability to pump blood is reduced because the left ventricle is enlarged and the heart muscle is weakened. This enlargement leads to less blood being pumped from the heart (a lower ejection fraction).
• Your healthcare provider wants to help assess the risk of surgery, such as coronary artery bypass graft surgery.

How do I prepare for this procedure?

• Do not eat for 4 hours before the test.
• You may take your medicines as usual with water or juice, unless your healthcare provider tells you not to.
• If you are diabetic, ask your provider for special instructions.
• Be sure to wear comfortable and loose-fitting clothing and comfortable shoes or slippers.

How is the procedure done?

During the RVG, electrodes are placed on your body for an electrocardiogram (ECG), which is a recording of the electrical activity of your heart. A radioactive chemical is injected into your vein. (The level of radiation is about the same as the amount you get during a chest X-ray.) The radioactive chemical attaches to red blood cells and passes through your heart. As these red blood cells fill the heart chambers, a camera that can detect the radioactive chemical shows an outline of the chambers. A computer then creates a movie of your heart beating.

The test is sometimes given while you are resting, then repeated with exercise or after you are given certain medicines.

What does the test result mean?

Abnormal results may indicate a heart attack, coronary artery disease, heart valve disease, or other heart problems.

When should I call my healthcare provider?

Your provider will review the results and let you know what the pictures show. Call your provider during office hours if:

• You have questions about the scan or its result.
• You want to make another appointment.