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 the pumping function of the heart.

The left ventricle is the chamber of the heart that pumps blood to the body. The strength of the left ventricle is measured by something called the ejection fraction. The ejection fraction 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 and can identify other problems in the left ventricle.

Why is this scan done?

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

The test 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, in which the heart does not pump efficiently, which causes fluid buildup in the lungs. The condition may also cause swelling (edema) in the legs.
• if you have a condition in which the heart's ability to pump blood is reduced because the left ventricle is enlarged and the muscle is weakened (dilated cardiomyopathy). This enlargement leads to less blood being pumped from the heart (lower ejection fraction).
• To help assess the risk of surgery such as coronary artery bypass graft surgery.

How do I prepare for this scan?

To prepare for the RVG, 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 healthcare provider for special instructions. Be sure to wear comfortable and loose-fitting clothing and comfortable shoes or slippers.

How is the scan done?

During the RVG, electrodes are placed on your body so that an electrocardiogram (ECG) can be watched. 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. Radioactive chemicals attach to red blood cells and pass through your heart. Since the red blood cells fill the heart chambers, the camera produces an outline of those 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.

The left ventricular ejection fraction (LVEF) is the most commonly used way to measure heart function. The ejection fraction is the proportion of blood that is pumped out from the ventricle with each heart beat.

When should I call my healthcare provider?

Your healthcare 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.