Heart Tests Heart Tests

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Learn about different tests and procedures to help diagnose heart diseases and conditions.

Heart imaging tests take pictures of your heart or its arteries or blood vessels to help your doctor see whether there are any problems.

Cardiac CT scan

A cardiac computed tomography (CT) scan, also called a "CAT scan,” is a painless, non-invasive imaging test that uses X-rays to take many detailed pictures of your heart and its blood vessels. Computers can combine these pictures to create a three-dimensional (3D) model of your whole heart.

This imaging test can help doctors find heart diseases or problems with the heart or blood vessels supplying blood to the heart or the rest of the body. This test may also be used to check the results of coronary artery bypass grafting or to follow up on abnormal findings from earlier chest X-rays. You may go to a medical imaging facility or a hospital for a cardiac CT scan. The scan itself usually takes only about 15 minutes. However, it can take more than an hour to prepare for the scan, including time to take medicines such as beta blockers to slow your heart rate or nitroglycerin to help dilate your arteries. Before the test, a healthcare provider will inject a contrast dye, often iodine-based, into a vein in your arm. This contrast dye highlights your blood vessels and creates clearer pictures. You may feel some discomfort from the needle or, after the contrast dye is injected, you may feel a warm flush briefly throughout your body or have a temporary metallic taste in your mouth.

The CT scanner is a large, tunnel-like machine that has a table. You will lie still on the table, and the table will slide into the scanner. Talk to your doctor if you are uncomfortable in tight or closed spaces to see if you need medicine to help you relax during the test. During the scan, the technician will monitor your heart rate with an electrocardiogram (EKG). You will hear soft buzzing, clicking, or whirring sounds when you are inside the scanner and the scanner is taking pictures. You will be able to hear from and talk to the technician performing the test while you are inside the scanner. The technician may ask you to hold your breath for a few seconds during the test.

Cardiac CT scans have some risks. In rare cases, the contrast dye may cause damage to the kidneys, particularly in people who have known chronic kidney problems. Your doctor or the imaging center may do a blood test to check your kidney function before the exam. In rare instances, some people may have an allergic reaction to the contrast dye. If you have a known allergy, you may still be able to receive contrast if you receive medicine ahead of time. There is a very slight risk of cancer, particularly in people younger than 40 years old who undergo multiple CT scans, because the test uses radiation.

Talk to your doctor and the technicians performing the test about whether you are or could be pregnant or are breastfeeding.

Rarely, people with lung diseases or heart failure may have breathing problems during cardiac CT scans if they are given beta blockers to slow their heart rates for this imaging test.

Coronary calcium scan

A coronary calcium scan is a CT scan of your heart that measures the amount of calcium in the walls of your coronary arteries. Buildup of calcium, or calcifications, are a sign of atherosclerosis or coronary heart disease.

A coronary calcium scan may be done in a medical imaging facility or hospital. The test does not use contrast dye and will take about 10 to 15 minutes to complete. A coronary calcium scan uses a special scanner such as an electron beam CT or a multidetector CT (MDCT) machine. An MDCT machine is a very fast CT scanner that makes high-quality pictures of the beating heart. A coronary calcium scan will determine a score that reflects the amount of calcium found in your coronary arteries, often referred to as an Agatston score. A score of 0 is normal. In general, the higher your score, the more likely you are to have coronary heart disease. If your score is high, your doctor may recommend more tests.

A coronary calcium scan has few risks. There is a very slight risk of cancer, particularly in people younger than 40 years old who undergo multiple CT scans. However, the amount of radiation from one test is similar to the amount of radiation you are naturally exposed to over one year. Talk to your doctor and the technicians performing the test about whether you are or could be pregnant.

Cardiac MRI

A cardiac magnetic resonance imaging (MRI) is a painless, noninvasive imaging test that uses radio waves, magnets, and a computer to create detailed pictures of your heart. No ionizing radiation is used in this type of imaging. This test can provide information on the type and seriousness of heart disease to help your doctor decide the best way to treat your condition.

Cardiac MRI can help your doctor diagnose heart diseases or problems with the blood vessels. Cardiac MRI can provide an accurate look at the heart muscle, heart chamber sizes and function, and connecting blood vessels. It is an excellent tool to look for scarring of the heart muscle like you might see in a heart attack, or inflammation of the heart as you might see with heart infection. Cardiac MRI may be performed as a resting study or used in combination with a stress medicine or exercise to look for low blood flow to the heart muscle. Cardiac MRI is also an excellent tool for evaluating tumors or clots in the heart and to help your healthcare provider monitor congenital heart disease or problems with your heart valves or aorta. Cardiac MRI may be used when images from other studies like an echocardiogram are not clear. It can also help clarify results from other imaging tests such as chest X-rays and chest CT scans.

Cardiac MRI may be done in a medical imaging facility or hospital. Before your procedure, a contrast dye to highlight your heart and blood vessels may be injected into a vein in your arm. Some cardiac MRI studies don’t require contrast. The MRI machine is a large, tunnel-like machine that has a table. You will lie still on the table and the table will slide into the machine. Talk to your doctor if you are uncomfortable in tight or closed spaces to see if you need medicine to help you relax during the test. You will hear loud humming, tapping, and buzzing sounds when you are inside the machine as pictures of your heart are being taken. You will be able to hear from and talk to the technician performing the test while you are inside the machine. Your heart rhythm will be monitored by an electrocardiogram, and your pictures will be coordinated with your heart beat. The technician may ask you to hold your breath for a few seconds multiple times during the test.

Cardiac MRI has few risks. In very rare cases, the contrast dye may cause an allergic-type reaction. Talk to your doctor and the technicians performing the test if you are or could be pregnant or are breastfeeding. If you are breastfeeding and need to receive MRI contrast, you may be instructed to discard your breastmilk for up to 2 days after the MRI study.

Tell your doctor if you have:

• A pacemaker or other implanted device because the MRI machine can damage these devices or cause a metallic implant to move.
• Had any prior surgeries, even if you do not know if metal was involved. Metal inside your body from previous surgeries (for example from clips or metal parts) can interfere with the MRI machine, cause the metal to move, cause artifacts in your images, or cause local heating. A lot of surgery-related metal is safe in the MRI machine, but it is important for the imaging team to carefully screen you ahead of time.
• Metal on your body from piercings, jewelry, or some transdermal skin patches because they can interfere with the MRI machine or cause skin burns. Tattoos may cause a problem because older tattoo inks may contain small amounts of metal.

Carotid ultrasound

Carotid ultrasound is a painless imaging test that uses high-frequency sound waves to create pictures of the inside of your carotid arteries. Your carotid arteries are the major blood vessels that supply oxygen-rich blood to your brain. Carotid ultrasound can help detect plaque buildup in one or both of your carotid arteries. It can also see whether the buildup is blocking blood flow to the brain. If combined with Doppler ultrasound, this test can also show how blood is moving through your arteries.

Carotid ultrasound is usually done in a doctor’s office or hospital. This test uses an ultrasound machine, which includes a computer, a screen, and a transducer. The transducer is a handheld device that sends and receives sound waves.

You will lie on your back on an exam table for your test. The ultrasound technician will put gel on your neck where your carotid arteries are located. The gel helps the sound waves reach your arteries. The technician will move the transducer against different areas on your neck. The transducer will detect the sound waves after they have bounced off your artery walls and blood cells. A computer will use the sound waves to create and record pictures of the inside of your carotid arteries and to show how blood is flowing in your carotid arteries. Test results will help your doctor plan treatment to remove or stabilize plaque and help prevent a stroke.

Carotid ultrasound has no risks because the test uses harmless sound waves. They are the same type of sound waves that doctors use to create and record pictures of a baby inside a pregnant woman.

Nuclear heart scan

A nuclear heart scan is an imaging test that uses special cameras and a radioactive substance called a tracer to create pictures of your heart. This imaging test can detect if blood is not flowing to parts of the heart and can diagnose coronary heart disease. It also can check for damaged or dead heart muscle tissue, possibly from a previous heart attack, and assess how well your heart pumps blood to your body.

You may go to a medical imaging facility or a hospital for a nuclear heart scan. Your healthcare team will monitor your heart during this test with an electrocardiogram (EKG). They will take two sets of pictures, each taking 15 to 30 minutes. The first set of pictures is taken right after an exercise or medicine stress test because some problems happen only when the heart is working hard or beating fast. Shortly after the stress test, the healthcare provider will inject the tracer into a vein in your arm. You may bruise at the injection site. You will lie still on a table that slides through a tunnel-like machine as the first set of pictures is taken. The second set of pictures will be taken on either the same day or the next day after your heartbeat has returned to normal.

Nuclear heart scans have few risks. In rare instances, some people have a treatable allergic reaction to the tracer. If you have coronary heart disease, you may have chest pain during the stress test. Medicine can help relieve your chest pain. Talk to your doctor and the technicians performing the test about whether you are or could be pregnant.

Echocardiography, or echo, is a painless test that uses sound waves to create moving pictures of your heart. The pictures show the size and shape of your heart and how well your heart is pumping blood. A type of echo called Doppler ultrasound shows how well blood flows through your heart's chambers and valves.

Echo can detect blood clots inside your heart, fluid buildup in the pericardium (the sac around the heart), tumors, and problems with the aorta. The aorta is the main artery that carries oxygen-rich blood from your heart to your body. Echo also can help your doctor find the cause of abnormal heart sounds, such as heart murmurs, due to damaged heart valves. Your doctor also might use echo to see how well your heart responds to certain treatments.

There are several types of echocardiography:

• Transthoracic echocardiography is the most common type of echo. It involves placing a device called a transducer on your chest after a gel is applied to your skin. The device sends special sound waves, called ultrasound, through your chest wall to your heart. As the ultrasound waves bounce off the structures of your heart, a computer in the echo machine converts them into pictures on a screen.
• Stress echocardiography is done as part of a stress test. During a stress test, you exercise or take medicine to make your heart work hard and beat fast. A technician will use echo to create pictures of your heart before you exercise and as soon as you finish.
• Transesophageal echocardiography gives your doctor a more detailed view of your heart. During this test, the transducer is attached to the end of a flexible tube. The tube is guided down your throat and into your esophagus (the passage leading from your mouth to your stomach). Your doctor will inject medicine into a vein to help you relax during the test.
• Fetal echocardiography is used to look at an unborn baby's heart to check for heart problems. When recommended, the test is commonly done at about 18 to 22 weeks of pregnancy. For this test, the transducer is moved over the pregnant person's belly.
• Three-dimensional (3D) echocardiography creates 3D images of your heart. This may be done as part of a transthoracic or transesophageal echo.

You may have the echocardiography in your doctor’s office or at a hospital. You won’t need to do anything to prepare for most types of echo. For a transesophageal echo, your doctor may ask you not to eat or drink for 8 hours before the test. Echocardiography usually takes less than an hour to do. For some types of echo, your doctor will need to inject saline or a special dye into one of your veins. This makes your heart show up more clearly on the echo pictures.

For most types of echo, you will remove your clothing from the waist up. Women will be given a gown to wear during the test. You will lie on your back or left side on an exam table or stretcher. Soft, sticky patches called electrodes will be attached to your chest to allow an electrocardiogram (EKG) to be done. An EKG is a test that records your heart's electrical activity.

For a transesophageal echo, you’ll be given oxygen through a tube in your nose. The back of your mouth will be numbed with gel or spray. Your doctor will gently place the tube with the transducer in your throat and guide it down until it is in place behind your heart. The pictures of your heart are then recorded as your doctor moves the transducer around in your esophagus and stomach. You shouldn’t feel any discomfort as this happens. Your throat might be sore for a few hours after the test.

If you have a transesophageal echo, you may experience some side effects from the medicine given to help you relax, such as problems breathing or nausea (feeling sick to your stomach). Rarely, the tube used causes minor throat injuries.

An electrocardiogram, also called an ECG or EKG, is a simple, painless test that detects and records your heart’s electrical activity. An EKG can show how fast your heart is beating, whether the rhythm of your heartbeats is steady or irregular, and the strength and timing of the electrical impulses passing through each part of your heart. You may have an EKG as part of a routine exam to screen for heart disease.

An EKG may be recorded in a doctor’s office, an outpatient facility, in a hospital before major surgery, or as part of stress testing. For the test, you will lie still on a table. A nurse or technician will attach several electrodes to the skin on your chest, arms, and legs. Your skin may need to be shaved to help the electrodes stick. The electrodes are connected by wires to a machine that records your heart’s electrical activity on graph paper or on a computer. After the test, the electrodes will be removed.

An EKG has no serious risks. EKGs don’t give off electrical charges such as shocks. You may develop a slight rash where the electrodes were attached to your skin. This rash usually goes away on its own without treatment.

Holter and event monitors are small, portable electrocardiogram devices that record your heart’s electrical activity for long periods of time while you do your normal activities. These monitors can record how fast your heart is beating, whether the rhythm of your heartbeats is steady or irregular, and the strength and timing of the electrical impulses passing through each part of your heart. Information from these recordings helps doctors diagnose an arrhythmia, or irregular heartbeat, and check whether treatments for the irregular heartbeat are working.

There are many types of monitors. Most monitors have electrodes with sticky adhesive patches that attach to the skin on your chest. Some monitors and electrodes used for long-term recording may be implanted under your skin to make it easier for you to bathe and perform your daily activities. Your doctor will explain how to wear and use the monitor and tell you whether you need to adjust your activity during the testing period.

You should avoid magnets, metal detectors, microwave ovens, electric blankets, electric toothbrushes, and electric razors while using your monitor because electrical signals can interfere with the monitor function. Usually, you will be instructed to keep electronic devices such as cell phones and tablets away from the monitor and keep it dry. After you are finished using the monitor, you will return it to your doctor’s office or the place where you picked it up. If you were using an implantable recorder, your doctor will remove it from your chest.

There is a small risk that the sticky patches that attach the electrodes to your chest can irritate your skin. You may have an allergic reaction to the electrode adhesive, but the reaction will go away once the electrodes are removed. If you are using an implantable recorder, you may get an infection or have pain where the device was placed under your skin. Your doctor can prescribe medicine to treat these problems.

A stress test measures how healthy your heart is and how well it works during physical stress. Some heart problems are easier to identify when your heart is working hard to pump blood throughout your body, such as when you exercise.

Your doctor may recommend this test if you have symptoms of a heart problem, such as shortness of breath, chest pain, dizziness, and a rapid or irregular heartbeat. If your doctor does find a problem, the stress test also can help your doctor choose the right treatment plan and determine what types of physical activity are safe for you.

You may do a stress test in your doctor’s office or a hospital. The test usually involves physical exercise such as walking on a treadmill or riding a stationary bicycle. If you are not able to exercise, your doctor will give you medicine that will make your heart work hard and beat faster, as if you were exercising. Your doctor may ask you not to take some of your prescription medicines or to avoid coffee, tea, or any drinks with caffeine on the day of your test, because these may affect your results. Your doctor will ask you to wear comfortable clothes and shoes for the test.

For the stress test, your doctor will put sticky patches called electrodes on your chest and attach a blood pressure cuff to your arm and a pulse monitor to your finger or another part of your body. Your doctor will measure your heart activity and blood pressure before you start the test. 

You will slowly start to exercise on a treadmill or stationary bicycle, and then gradually increase the treadmill speed or bicycle resistance until your heart is working at the target heart rate for your age. Most often, a stress test includes an electrocardiogram to measure your heart’s electrical activity and heart rate, and a blood pressure monitor as you exercise. Your doctor may also measure your blood oxygen level. During the test, you will exercise for about 10 to 15 minutes. Your doctor will stop the test if you show any sign of a heart problem or if you are too tired to continue the test. If you are not able to exercise, your doctor will give you medicine over a 10- to 20-minute period through an intravenous (IV) line into one of your blood vessels.

Your doctor may use echocardiography, cardiac MRI, or a nuclear heart scan to take images of your heart during or right after the stress test. These tests will show how well blood is flowing through your heart and how well your heart pumps blood when it beats. If your doctor also wants to see how well your body uses oxygen you may be asked to wear a mask or mouthpiece to measure the gases that you breathe out during the stress test.

After the stress test, your doctor will measure your heart activity and blood pressure to make sure that both measurements are back within the normal range. You should be able to return to your normal activities right away.

Your doctor will carefully monitor you throughout the test to lower the risk of complications caused by the exercise or medicine used to raise your heart rate. Intense exercise during the test can rarely cause some heart problems such as chest pain or irregular heartbeats; these usually go away after exercise. Some stress medicines temporarily lower your blood pressure. If your doctor gives you medicine to make your heart beat harder instead of having you exercise, there is a small risk of developing certain heart problems after the test.

Coronary angiography is a procedure that uses contrast dye, usually containing iodine, and X-ray pictures to detect blockages in the coronary arteries that are caused by plaque buildup. Blockages prevent your heart from getting oxygen and important nutrients.

This procedure is used to diagnose heart diseases or after abnormal results from tests such as an electrocardiogram (EKG) or an exercise stress test. If you are having a heart attack, coronary angiography can help your doctors plan your treatment.

Coronary angiography is often done in a hospital. You will stay awake, but receive medicine to relax during the procedure. Coronary angiography is done via a cardiac catheterization procedure. For this, your doctor will clean and numb an area on the arm, groin or upper thigh, or neck before making a small hole in the skin and a blood vessel. Your doctor will insert a catheter tube into your blood vessel. Your doctor will take X-ray pictures to help place the catheter in your coronary arteries. After the catheter is in place, your doctor will inject the contrast dye through the catheter to highlight blockages and will take X-ray pictures of your heart. If blockages are detected, your doctor may use percutaneous coronary intervention, also known as coronary balloon angioplasty, usually with the use of a stent (a wire mesh that helps keep an blocked artery open), to improve blood flow to your heart.

After coronary angiography, your doctor will remove the catheter and close and bandage the opening on your arm, groin, or neck. You may develop a bruise and soreness where the catheter was inserted. You will stay in the hospital for a few hours or sometimes overnight. During this time, your healthcare team will check your heart rate, blood pressure, and the catheter insertion site.

Coronary angiography is a common procedure that rarely causes serious problems. However, as with any invasive procedure involving the heart, there is some risk. These risks include bleeding, allergic reactions to the contrast dye, kidney problems, infection, blood vessel damage, arrhythmias, and blood clots that can trigger a heart attack or stroke. The risk of complications is higher in people who are older or who have chronic kidney disease or diabetes.

Cardiac catheterization is a medical procedure used to diagnose and treat some heart conditions. During cardiac catheterization, a long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin or upper thigh, or neck through a small incision, or cut. The catheter is then threaded through your blood vessels to your heart.