Nuclear Cardiac Stress Test

Overview What to Expect Our Expertise & Doctors FAQ

What is a nuclear cardiac stress test?

A nuclear cardiac stress test is used to assess the blood flow to your heart muscles during exercise and rest. It is also called a nuclear perfusion scan or myocardial perfusion imaging.

A nuclear cardiac stress test is a common test used to diagnose heart problems. It may be used to complement a regular electrocardiogram (ECG), which detects abnormal electrical activity in the heart and pinpoints heart blockages exactly.

How it works

During the procedure, your doctor will inject a small amount of a radioactive compound (called a tracer) into a vein in your arm. The tracer will be swept from your blood quickly by heart muscle cells.

Your doctor will take 2 sets of images of your heart using a gamma camera — when you are resting and after you exercise. If radioactivity is not seen in parts of the heart, this means that there is a lack of blood supply to that part.

Why do you need a nuclear cardiac stress test?

Your doctor may request a nuclear cardiac stress test to:

Assess blood flow to your heart walls.
Determine the cause of chest pain if you experience chest pain for no clear reason or during exercise.
Check if any coronary (heart) arteries are blocked and the extent of any blockage.
Find out the extent of damage to your heart if you experienced a heart attack. If the tracer cannot be detected in some areas of the heart, this could indicate scar tissue, or damaged heart tissue from a heart attack.
Assess blood flow to your heart after a heart bypass surgery or angioplasty (re-opening of blocked heart arteries using a balloon or a stent).

Who should not undergo a nuclear cardiac stress test?

You should not undergo this test if you:

Have a flu with fever.
Have an infectious disease such as sore eyes or chicken pox.
Are pregnant or breastfeeding, to avoid exposure to radiation.
Are feeling lethargic.

What are the risks and complications of a nuclear cardiac stress test?

A nuclear cardiac stress test is generally safe. Rare complications include:

Abnormal heart rhythms (arrhythmias) occurring during a stress test. This is usually temporary. Life-threatening arrhythmias due to the test are rare.
Dizziness or chest pain can happen during a nuclear cardiac stress test. Other mild and brief symptoms may include feeling anxious, feeling out of breath, nausea, shakiness, headache and flushing during the test.
Heart attack due to the test. This is extremely rare.
Low blood pressure during or immediately after the exercise. You may feel dizzy or faint but will recover after the stress test.

How do you prepare for a nuclear cardiac stress test?

To prepare for the test:

Stop taking medications containing theophylline 48 hours before the test.
Avoid taking medications and food and drinks containing caffeine 12 hours before the test.
Shave your chest if you are a male patient. This allows the electrodes to stick to your skin better.
Wear or bring along exercise attire and shoes for exercising, or walking on the treadmill.
Have a light meal before the test.

What can you expect in a nuclear cardiac stress test?

The nuclear cardiac stress test has 2 parts:

Rest scan
Stress scan

Estimated duration

Depending on the type of nuclear tracer used, the complete test may take 2 – 6 hours.

A nuclear cardiac stress test uses a radioactive tracer to assess blood flow to your heart muscles during exercise and rest.

Before the procedure

Your doctor will insert an intravenous line into your arm to inject the radioactive tracer.

During the procedure

If you are undergoing a rest scan, your doctor will:

Inject the radioactive tracer.
Wait for the tracer to circulate through your heart's blood vessels.
Take images of your heart.

If you are undergoing a stress scan, your doctor will:

Inject the radioactive tracer.
Place electrodes on your chest. The electrodes are connected to an electrocardiogram to monitor electrical signals that trigger your heartbeat.
Ask you to exercise on a treadmill. If you are unable to exercise, your doctor will inject a medication to increase blood flow to your heart instead.
Monitor your blood pressure during the test.
Take images of your heart when your heart rate peaks.

After the procedure

Your doctor will compare the 2 sets of images to see how blood flows through your heart.

Care and recovery after a nuclear cardiac stress test

After the test, you may return to normal activities. Take note to:

Drink lots of fluid for the next 1 – 2 days to flush out any remaining radioactive tracer from your body.
Minimise contact with infants and pregnant mothers for 24 hours after the test. This avoids any risk of radiation exposure to them.
(If you are breastfeeding) Only resume breastfeeding 24 hours after the test.

Why choose Gleneagles Hospital?

At Gleneagles, your recovery is our priority. Established in Singapore for more than 60 years, our team of cardiologists and cardiothoracic surgeons work closely with multidisciplinary specialists to provide holistic care for your heart conditions.

We are equipped to conduct a range of cardiac tests, such as a nuclear cardiac stress test, in a comfortable and private setting.

Our cardiologists

At Gleneagles Hospital, we offer a comprehensive heart and vascular programme through our team of heart specialists. We will treat your heart condition holistically with expert help from our specialists.