Heart Tests

What is an ECG?

An ECG is a 10 second recording of the electrical activity of the heart. The test takes 5 to 10 minutes to perform. It involves placing small adhesive electrodes on your chest, arms, and legs to record your heart’s electrical activity. You do not need to prepare for this test. It is painless and harmless. In rare cases the adhesive electrodes may irritate the skin.

Why do I need an ECG?

The ECG is a key test for the heart. Through the different electrodes, it provides 12 electrical tracings of your heart’s electrical activity taken from different angles. For this reason, it is often called a 12-lead ECG.

An ECG is particularly useful when performed while you are experiencing symptoms. It reveals whether your heart rhythm is regular or irregular, and whether your heart rate is normal, too fast, or too slow. It provides clues about the health of your heart muscle.

What is a Holter Monitor?

A Holter monitor is a portable device that can continuously record your heart rhythm over 24 hours or longer. The test is performed by placing electrodes on your body. These are connected by cables to a portable device that is strapped to your chest. After the monitor is fitted, you may leave the practice and go about your usual activities over the next 24 hours or longer if required. You will need to keep a diary of your symptoms so that these can be matched to your recording. After the specified time period, you will be asked to return the monitor for analysis.

You do not need to prepare for this test. The test is painless and harmless. In rare cases the adhesive electrodes may irritate the skin.

Why do I need Holter Monitoring?

If your symptoms “come and go”, an ECG performed at your appointment is unlikely to reveal the problem, unless you are experiencing symptoms at the time of the recording. Holter monitoring improves the chance of detecting whether an abnormal heart rhythm is responsible for your symptoms.

What is an event monitor?

An event monitor is a portable device that continuously monitors your heart rhythm over several days. It appears similar to a holter monitor but has a major difference. It does not record your heart rhythm for the entire period that it is worn, but instead has a looping memory function that records your ECG for a period of time, such as 5 minutes.

When you experience your symptoms, you must push a button to activate the recorder so that it stores your ECG for the period before and during your symptoms. If you faint and push the button after you recover, it will record your ECG during the time you felt faint and passed out, and right after you pushed it.

How is an event monitor test performed?

The test is performed by placing electrodes on your body. These are connected by cables to a portable device that is strapped to your chest. After the monitor is fitted, you may leave the practice and go about your usual activities over the next 7 days or longer if required. You will need to activate the device when you experience symptoms, and keep a diary of your symptoms so that these can be matched to your recording. After the specified time period, you will be asked to return the monitor for analysis.

You do not need to prepare for this test. The test is painless and harmless. In rare cases the adhesive electrodes may irritate the skin.

Why do I need an event monitor test?

If your symptoms occur infrequently, say once or twice a week, then an ECGs and holter monitors are unlikely to reveal the problem, unless you happen to experience your symptoms at the time of the recording. Event monitoring improves the chance of detecting whether an abnormal heart rhythm is responsible for your symptoms.

What is an echocardiogram?

An echocardiogram, or echo, is an ultrasound scan of the heart performed from the front or side of the chest. It is also known more specifically as a transthoracic echocardiogram or TTE. It provides moving images of the heart used to assess the structure and function of the cardiac chambers and valves.

How is an echo performed?

This test takes around 30 min to complete. You will first need to remove the upper layer of clothing and change into a gown. A technician will put a gel on your chest. The gel improves the quality of the imaging. It will feel cool and is harmless to your skin.

An imaging probe will be placed firmly against the side or front of your chest to acquire ultrasound images of your beating heart. You will be asked hold your breath briefly at different times during the test.

You do not need to prepare for this test. It is a non-invasive test and carries no risk.

Why do I need an echo?

An echo helps us determine if your heart is well formed and functioning normally. Heart rhythm disorders are sometimes associated changes in the structure or function of the heart. If these are present, an echo is likely to reveal them.

What is an exercise stress test?

An EST examines your heart’s electrical system under conditions of normal exercise. It involves monitoring your 12-lead ECG while you are resting, then during exercise, and finally as you recover from exercise.

How is an EST performed?

An EST takes around 30 min to perform. You will be attached to a 12-lead ECG monitor, with small adhesive electrodes placed on your chest, arms, and legs to record your heart’s electrical activity. A blood pressure cuff will be placed on your arm.

You will be asked to walk on a treadmill. The speed and incline of the treadmill will increase every 3 min till you are jogging or running. Your ECG and blood pressure will be monitored for as long as you are able to exercise, or until your target heart rate is achieved. This normally takes around 10 min.

After your exercise is complete, you will be monitored for several minutes while you are resting on a bed.

Do I need to prepare for this test?

You may be asked to stop taking certain cardiac medications prior to the test. This will be confirmed prior to your procedure. If you are unsure, please contact the Clinic for clarification.

Please wear comfortable two-piece clothing allowing access to the chest area and shoes suitable for running in. For men, areas of chest hair may need to be shaved to allow the electrodes to adhere to the skin. If required, the technician will perform this at the time of the test.

Are there any risks involved?

An EST involves only normal levels of exercise, adjusted for your age and gender. If your heart is at risk of exercise induced arrhythmias or insufficient blood supply due to narrowed arteries, then an EST may reveal these risks. Heart attack, cardiac arrest, and death are extremely rare.

Why do I need an EST?

If you have an exercise-induced arrhythmia, an EST may allow us to capture a 12-lead ECG of the rhythm disturbance, providing important clues about the mechanism of the arrhythmia.

What is a stress echo?

A stress echo combines an exercise stress test with echocardiography. It examines your heart’s electrical function and pump function under conditions of rest and normal exercise.

How is a stress echo performed?

A stress echo normally takes around 30 min to perform. You will be attached to a 12-lead ECG monitor, with small adhesive electrodes placed on your chest, arms, and legs to record your heart’s electrical activity. A blood pressure cuff will be placed on your arm.

A resting echo will be performed while you are lying in bed. A technician will put a gel on your chest. The gel improves the quality of the imaging. It will feel cool and is harmless to your skin. An imaging probe will be placed firmly against the side or front of your chest to acquire ultrasound images of your beating heart. You will be asked to hold your breath briefly at different times during the test.

You will then be asked to walk on a treadmill. The speed and incline of the treadmill will increase gradually till you are jogging or running. Your ECG and blood pressure will be monitored for as long as you are able to exercise, or until your target heart rate is achieved. This normally takes around 10 min.

Once your exercise is complete, you will return to the echo bed to record more pictures. You will be asked to breathe out and hold your breath briefly several times. This allows clear pictures to be recorded.

It is very important that you do your best to hold your breath during this part of the examination because the technician has only 1-2 minutes to obtain these images before your heart slows down to a normal rate.

Do I need to prepare for this test?

You may be asked to stop taking certain cardiac medications prior to the test. This will be confirmed prior to your procedure. If you are unsure, please contact the Clinic for clarification.

Please wear comfortable two-piece clothing allowing access to the chest area and shoes suitable for running in. For men, areas of chest hair may need to be shaved to allow the electrodes to adhere to the skin. If required, the technician will perform this at the time of the test.

Are there any risks involved?

A stress echo involves only normal levels of exercise, adjusted for your age and gender. If your heart is at risk of exercise induced arrhythmias or insufficient blood supply due to narrowed arteries, then a stress may reveal these risks.

Why do I need a stress echo?

A stress echo reveals areas of the heart muscle receiving insufficient blood supply during exercise. In addition, if you have an exercise induced arrhythmia, a stress echo may allow us to capture a 12-lead ECG of the rhythm disturbance, providing important clues about the mechanism of the arrhythmia.

What is a TOE?

TOE is short for transoesophageal echocardiogram. This is a specialized ultrasound scan of the heart performed under sedation or general anaesthesia using an ultrasound probe passed through the mouth and into the gullet. This allows us to capture clear images of the structures in the back of the heart which cannot be clearly visualized with a standard echo performed from the front or side of the chest. It most often used to make sure there is no evidence of blood clot in your heart prior certain arrhythmia procedures.

How is a TOE performed?

A TOE normally takes around 30 min and is performed by a specially trained cardiologist.

• A technician will spray your throat with a medicine to numb it and suppress the gag reflex.
• You will lie down in a bed and a mild sedative will be given through an intravenous line in your arm.
• Adhesive electrodes will be placed on your chest and limbs and an ECG will be performed.
• The doctor will gently guide a thin, flexible ultrasound probe through your mouth and down your throat, and you will be asked to swallow as it goes down.
• The transducer on the end of the probe will send sound waves to your heart and will collect the echoes that bounce back. These echoes become pictures that show up on a video screen. This part of the test takes 10 to 15 minutes.
• When the doctor is finished taking pictures, the probe, IV line, and electrodes are removed, and nurses watch you until you are fully awake.

 What happens after a TOE?

• You may have a little trouble swallowing right after the test, but this will go away within a few hours.

• Your throat may be numb for a short time. Don’t eat or drink anything until the numb feeling goes away because you could choke.

• It is common to have a sore throat for a day or two after the test.
• Because of the sedative you get during the procedure, don’t drink alcohol for a day or two.

 Do I need to prepare for this test?

Do not eat or drink anything for 6 h prior to the test, except for your usual tablets which may be taken with a sip of water. Avoid alcohol for 3 days before the test.

You will need to arrange for someone to drive you home after the test, as the sedative medication may take some time to fully wear off.

 Are there any risks involved?

A sore throat for a day or two is common after the procedure. Injury to your lips, teeth, throat, or gullet is unusual. Serious or life threatening complications are extremely rare.

Why do I need a TOE?

A TOE is used to visualize the deep structures of the heart. It is often used to ensure no clots are present in heart before performing procedures such as DCR (electric shock to the heart to restore normal rhythm) or arrhythmia ablation.

What is a cardiac CT?

A cardiac CT scan is an advanced X ray scan that takes many detailed pictures of your heart and its blood vessels. These pictures are combined by a computer to create a 3D model of your heart and surrounding blood vessels.

How is a cardiac CT performed?

Your cardiac CT scan will be performed in a hospital or medical imaging facility. The scan itself takes 15 minutes to complete. However, including preparation time, the whole process may take an hour or more.

You may be given a medication called a beta blocker to slow your heart rate down in preparation for your scan. This improves the quality of the scan images. Just before the scan, a contrast dye containing iodine may be administered via an intravenous line in your arm. This dye allows different structures of the heart to be highlighted in the scan images, such as the coronary arteries or cardiac chambers.

The CT scanner is a large, tunnel-like machine with a table that goes through it. You will be lying still on the table, as it slides into the scanner. The scan is brief, however if you feel you may be uncomfortable in narrow or closed spaces then do mention this to staff prior to the scan.

During the scan, your ECG will be monitored. You will hear soft buzzing, clicking, and whirring sounds within the scanner. You may also be asked by the technician you to hold your breath for a few seconds during the test.

 Do I need to prepare for a cardiac CT?

There is no special preparation required for a cardiac CT scan. You may continue taking your usual medications, but do avoid caffeine and smoking for 4 hours before the test.

Wear loose and comfortable clothing for the scan. You may be given a gown to wear. Metal objects such as jewelry will affect the scan images and will need to be removed prior to the test. Women will be asked to remove bras that contain metal underwire. Piercings may need to be removed depending on their location.

You must inform the staff performing the test if you are or could be pregnant. You may be asked to take a pregnancy test. Alternatively, it may be best to cancel the scan and depend on information from an alternative scan.

Are there any risks involved?

You may feel some discomfort while the intravenous line is placed in your arm. The contrast dye injection will briefly make you feel warm and cause a metallic taste in your mouth.

An allergic reaction to the contrast dye are rare. There is a very slight increase in the overall risk of cancer, particularly in those aged under 40 years. This is because the test uses radiation, approximately equivalent to what you would naturally be exposed to over two years.

Another risk is of an incidental finding, which is something that doesn’t cause symptoms now but may require further tests after being identified.

You must inform the staff performing the test if you are or could be pregnant. You may be asked to take a pregnancy test. Alternatively, it may be best to cancel the scan and depend on information from an alternative scan.

Why do I need a cardiac CT?

A cardiac CT scan can be performed in different ways for different purposes. It may be used to evaluate coronary artery disease, calcium buildup in the coronary arteries,problems with the aorta, problems with heart function and valves, and pericardial disease.

Prior to a catheter ablation procedure, a cardiac CT scan is sometimes used to obtain a roadmap to guide the operator during the procedure.

What is a cardiac MRI?

A cardiac MRI scan uses a strong magnet and radio waves to create detailed 3D images of the heart. It avoids the use of ionizing radiation necessary for other scans such as X rays and CT scans.

Some cardiac MRIs might involve the injection a contrast agent called gadolinium. This may be used to evaluate the blood supply to the heart muscle, or to highlight blood vessels, cardiac chambers, or scar tissue within the heart muscle walls.

Our Clinic normally arranges cardiac MRIs to be performed at the Alfred Hospital. We have close clinical and research ties with the cardiac imaging service at the Alfred, which is Victoria’s premier cardiac MRI centre, and a leading imaging centre both nationally and internationally.

How is a cardiac MRI performed?

A cardiac MRI is performed in a hospital or medical imaging facility. The scan normally takes 60 to 90 min including preparation time. You will be asked to change into a comfortable gown before the scan. An ECG will be fitted to monitor your heart.

You will lie on the scanner bed and an intravenous line will be placed in your arm if a contrast injection is required. The radiographer will give you headphones so that you can communicate during the scan. The headphones also block out noise from the MRI scanner which can be quite noisy at times. Special detectors enclosed in plastic will be placed on your chest. The bed will move inside the MRI machine which is shaped like a tunnel.

The radiographer will perform the MRI scan from the next room, called the control room. You will hear humming and knocking sounds during the scan. You will be asked to hold your breath at different times to allow the best pictures to be taken. If you feel uncomfortable or anxious at any time during the scan, you will be able to communicate with the radiographer who can then bring you back out of the tunnel if necessary.

If your scan requires contrast, the supervising doctor will administer this through your intravenous line. The gadolinium is very safe, but as with all medications, allergic reactions may occur. The hospital radiology department or radiology practice where you are having the scan will be equipped to deal with this should it arise.

If you are having a cardiac stress perfusion MRI which assesses blood flow to the heart, then injection of both contrast and a medication called adenosine will be given during the scan. Adenosine causes most people to feel briefly flushed and may cause discomfort around the chest and jaw. These sensations pass after a few seconds to minutes. Adenosine washes out of the system within minutes and has no long term consequences. A follow-up series of images is taken at the end of the exam which requires another contrast injection, but no adenosine.

 Do I need to prepare for a cardiac MRI?

You will be asked to complete a safety questionnaire prior to the scan to ensure that you are suitable. If you have a history of kidney disease, a blood test will be required to ensure that the contrast medium can be administered safely.

No special preparation is required unless you are having a scan specifically to assess blood flow to your heart muscle called a cardiac stress perfusion MRI. If so, you will need to avoid caffeine for 24 h prior to the scan. This includes tea, coffee, herbal teas, even decaffeinated coffee and soft drinks containing caffeine. Your doctor will tell you beforehand if this is necessary.

Are there any risks involved?

MRI scanning itself has no after effects. Most people can undergo cardiac MRI scanning, however there are some restrictions on individuals with certain types of implanted cardiac devices such as pacemakers and ICDs which may not be compatible with MRI scanning. This especially applies to older generation devices.

MRI scanning is usually well tolerated, but if you are uncomfortable in enclosed spaces or suffer from claustrophobia, then do inform the staff prior to your scan. You may not be able to complete the scan, in which case we may need to depend on information from an alternative scan.

If your scan requires a contrast injection of gadolinium, this is very safe and causes no issues with the following exceptions:

• Transient reactions. Some people experience transient headache, nausea, or dizziness following the injection. These symptoms resolve quickly and without treatment.
• Allergy-like reactions. Rarely (1 in 1,000 individuals), an itchy skin rash occurs which settles in 1 h. Very rarely, (1 in 10,000 individuals), this may progress to a severe anaphylactic reaction causing difficulty breathing and swelling of the lips and mouth. Severe reactions usually respond well to standard emergency drug treatments which are available in all radiology facilities that administer gadolinium.
• Nephrogenic systemic fibrosis (NSF). Nephrogenic systemic fibrosis (NSF) is a rare debilitating disease causing diffuse scarring of the internal organs including skin contractures. It is extremely rare and has only ever been documented patients with either renal transplantation or severe pre-existing kidney disease. The risk of NSF in those with severe pre-existing kidney disease is estimated to be well below 1 in 100 injections. To avoid this risk, your kidney function will be tested and gadolinium will be avoided if you have moderate to severe impairment of your kidney function.
• Pregnancy and possible pregnancy. If you are or may be pregnant, or are trying to conceive, please inform your doctor. Contrast-enhanced cardiac MRI scans provide excellent clinical information about your heart. However, for the purpose of evaluating and treating cardiac arrhythmias, gadolinium is unlikely to be essential. Our Clinic therefore avoids using contrast-enhanced cardiac MRI in all individuals who are pregnant, possibly pregnant, or trying for to conceive.

 Why do I need a cardiac MRI?

A cardiac MRI scan can be performed in different ways for different purposes. It provides accurate information about your heart structure and function, and in many areas provides more detailed images of your heart than can be obtained by echo or CT scanning. It may be used to evaluate scarring in the heart muscle tissue, coronary artery disease, problems with the aorta, problems with heart function and valves, pericardial disease, and blood flow.

Prior to a catheter ablation procedure, a cardiac MRI scan is sometimes used to obtain a roadmap to guide the operator during the procedure.

What is a coronary angiogram?

A coronary angiogram is a test that uses x-ray imaging and contrast dye to view the coronary arteries. The coronary arteries are the blood vessels that deliver blood to the muscle of the heart. The test allows your doctor to visualize the anatomy of the coronary arteries and is typically used to identify narrowings or blockages along their course.

Who requires a coronary angiogram?

A coronary angiogram may be required to evaluate the cause of chest pain, breathlessness, or ventricular arrhythmias. It may be used to plan a further procedure such as coronary angioplasty, bypass surgery, or valve surgery. In special cases, a coronary angiogram may be required during an arrhythmia ablation procedure, avoid injury to the coronary arteries which can occur if ablation is performed to close to these vessels.

How do I prepare for a coronary angiogram?

You will receive a letter from the hospital bookings clerk or doctor’s secretary outlining the date, time, and other details of your hospital admission for the procedure. A nurse may call you to confirm your personal and medical details. You may need to attend a blood collection service for a blood test approximately 1 week prior to your procedure. If so, a blood test request slip will be provided.

You will receive specific instructions about any medications changes that are necessary prior to your procedure. If you are unsure about the instructions, please do contact the clinic for clarification. You will be required to fast for at least six hours before your procedure. If your procedure is in the morning or early afternoon, do not eat or drink after midnight, except for a sip of water to help you swallow your pills. If your procedure is in the mid to late afternoon, you may have a light, early breakfast.

How is a coronary angiogram performed?

A doctor with special training performs the procedure with a team of nurses and technicians. The procedure is done in a hospital cardiac catheterization, or cath lab for short.

• An intravenous line will be placed in your arm for the administration of a sedative, and any other necessary medications during the procedure.
• The nurse will clean and shave the area where the doctor will be working. This is usually in the groin area, although sometimes the wrist may be used.
• A local anesthetic is usually given to numb the needle puncture site.
• The doctor will make a needle puncture through your skin and into a large blood vessel.  A small straw-sized tube (called a sheath) will be inserted into the vessel. The doctor will gently guide a catheter (a long, thin tube) into your vessel through the sheath. A video screen will show the position of the catheter as it is threaded through the major blood vessels and to the heart. You may feel some pressure, but you shouldn’t feel any pain.
• Various instruments may be placed at the tip of the catheter. They include instruments to measure the pressure of blood in each heart chamber and in blood vessels connected to the heart, view the interior of blood vessels, take blood samples from different parts of the heart, or remove a tissue sample (biopsy) from inside the heart.
• When a catheter is used to inject a dye that can be seen on X-rays, the procedure is called angiography.
• When a catheter is used to clear a narrowed or blocked artery, the procedure is called angioplasty or a percutaneous coronary intervention (PCI).
• The doctor will remove the catheters and the sheath. Your nurse will put pressure on the site to prevent bleeding. Sometimes a special closure device is used. The procedure lasts about an hour.

What happens after coronary angiogram?

You will be transferred to a recovery room for a few hours. During this time, you have to lie flat.

• Pressure will be applied to the puncture site to stop the bleeding.
• You will be asked to keep your leg straight and will not be able to get out of bed.
• Your heartbeat and other vital signs (pulse and blood pressure) will be checked during your recovery.
• Report any swelling, pain or bleeding at the puncture site, or if you have chest pain.
• Before you leave the hospital, you will receive written instructions about what to do at home.

Discharge information

Your doctor will explain the results of the procedure and the need for any further procedures. The information about your heart and coronary arteries will help your doctor to recommend the best treatment for you. Unless coronary angioplasty or stenting is required you will be discharged home if someone is available to stay with you. You should avoid heavy lifting and stairs (if possible) for three days after your procedure and generally take things easy.

What are the risks involved?

As with any medical tests, there are some risks, but serious side effects are rare. Most people have no trouble, and the benefits usually far outweigh the risks. You should discuss with your doctor any questions or concerns that you may have about coronary angiography.