Cardiac Testing

What is a 12 lead ECG?

An electrocardiogram (ECG, also known as EKG) captures the electrical activity of the heart, including the rate and rhythm. A 12 lead ECG can be used to identify arrhythmia, conduction abnormalities, some abnormal heart structures, and ischaemia.

You will often also have an ECG during other forms of cardiac testing, such as echocardiogram or exercise testing.

What happens during an ECG?

After you have laid down on the bed, a cardiac technician will attached adhesive electrodes to your limbs and chest and attach these to a ECG machine, which will create an image (“tracing”) of the heart rate and rhythm. There is no pain and no risks associated with ECG. You may have an ECG during a consultation, but usually you will not see a doctor for this test. A cardiologist will interpret the ECG tracings before sending a report to your referring doctor.

How do I prepare for an ECG?

Nil, although you may prefer to wear a two-piece outfit (e.g. shirt and pants or skirt), as you will be asked to lift up or remove your shirt to attach arm and chest electrodes (ladies can leave their bra on). You may be asked to remove tights/stockings or slightly adjust your pants to attach the leg electrodes. If you have hairy legs or chest the technician may shave a small patch in order to stick the electrodes to the skin. It is best to avoid moisturiser on the day of the test as this may affect the adherence of electrodes.

How long does an ECG take?

An ECG takes only about 5 minutes, but allow around 15 minutes for your appointment to check in and pay the bill afterwards.

What is a 24 hour blood pressure monitor?

A 24 hour blood pressure monitor – also known as an ambulatory blood pressure monitor – is a wearable device that measures your blood pressure as you go about your daily life over a 24 hour period. This gives insight into the variability of your blood pressure, allowing identification of hypotension (low blood pressure), hypertension (high blood pressure), response to blood pressure medication, or other abnormalities.

What happens during ambulatory blood pressure monitoring?

A blood pressure cuff, like that you may have worn previously in your doctor’s office, is placed on the upper arm and attached to a small recorder which is carried over the shoulder. The monitor is worn non-stop for a 24 hour period and measures your blood pressure at regular intervals, including while you sleep. You will be asked to keep a diary of your activities and symptoms so that the interpreting cardiologist can correlate any symptoms with blood pressure abnormalities. You ought to go about your usual activities, such as working, exercising, driving a car, and so on, to give an accurate representation of your blood pressure, but you will not be able to bathe, shower, or swim. You will return to the office with the device after 24 hours. You will see a cardiac technician for this test and your results will be reviewed and reported by a cardiologist.

How do I prepare for 24 hour blood pressure monitoring?

As you will not be able to shower, bathe, or swim for the duration of the 24 hour monitoring period, please ensure that you are refreshed before attending. Wear a loose, short-sleeved shirt to your appointment; you will be asked to pull up the sleeve or slip your arm out of the shirt so the cuff can be attached. There are no risks associated with this type of test.

Please ensure that you are available to return the monitor along with your symptom & activity diary to us at the end of the 24 hour period. This will usually just take a few minutes; the technician will give further instructions for return at the time of fitting the monitor. 

What is coronary calcium scanning?

A HeartRisk scan – also known as coronary calcium scoring/scanning – measures the degree of calcium build up in the vessels of the coronary (heart) arteries. Coronary calcium scoring uses computed tomography (CT) to scan the heart, looking for hardening and narrowing of the arteries. Your calcium score is interpreted as a percentile indicating your risk of experiencing a major cardiac event, such as heart attack, over the next several years compared to others of your age and sex.

What does coronary calcium scanning involve?

You will be asked to undress from the waist up (gowns provided). A technician will measure your blood pressure and perform a resting ECG. You will then be asked to lie on the CT scanner sliding bed and ECG leads will be attached to your chest. You will be asked to hold your breath for a few seconds whilst the bed moves through the scanner. You will not feel any discomfort during the procedure and there is no risk.

How long does coronary calcium scanning take?

The HeartRisk scan will take approximately 20 minutes.

How do I prepare for a coronary calcium scan?

No special preparation is required for HeartRisk scanning, but it is recommended that you wear a two-piece outfit.

Do I need a referral?

Western Cardiology does not require patients to have a doctor’s referral for HeartRisk scanning. Please note that all other forms of cardiac testing do require a referral.

What is an echocardiogram?

Transthoracic echocardiogram (or “echo”) visualises the heart and blood flow using ultrasound in order to assess the structure and function of the heart. You may be referred for an echocardiogram to assess –

• the function of the heart valves and check for regurgitation
• the size, structure, movement and behaviour of the heart
• stenosis (narrowing) of the heart valves and large external vessels
• the presence of tumours, blood clots, and inflammation of the pericardium
• other forms of heart disease and changes to any of the above over time.

We offer both adult and paediatric echocardiography.

What happens during an echocardiogram?

You will be asked to undress to the waist and the sonographer will attach ECG electrodes before asking you to lie on your side. The room is darkened to better allow them to see the ultrasound images. The sonographer applies conductive jelly and moves a small transponder around your chest. You may be asked to briefly hold your breath or move slightly to improve imaging, and apart from the pressure of the probe on the chest there is nothing else to feel and no risks.

How long does echocardiography take?

Approximately 45 minutes.

How to prepare for an echocardiogram?

Wear a two-piece outfit. No other preparation is necessary.

Like a Holter monitor, the event monitor (sometimes called King of Hearts monitor) is a wearable electrocardiogram device used to record the heart rate and rhythm. However, the event monitor is patient activated: when you experience symptoms and activate the device, a short recording (tracing) of the heart beat is captured.

Why have I been referred for event monitoring?

Cardiac symptoms sometimes come and go and may not always be present during a typical brief 12 lead ECG or even a 24 hour Holter recording. By wearing the event monitor for a week or more, there is a greater likelihood of detecting abnormalities such as arrhythmia. Event monitoring can be used to help correlate symptoms (such as dizziness or shortness of breath) with changes to the heart beat. It may also be used to assess the effectiveness of certain medications.

What does event monitoring involve?

Adhesive electrodes will be placed on the chest and connected to a small recorder. When you experience symptoms, you will press a button to activate the device and note the event in a diary. The device may be used for a week or longer, and you should go about your normal activities of daily living. It may be temporarily removed for showering.

How do I prepare for event monitoring?

• Wear a two-piece outfit. You will be asked to remove your top for application of the electrodes.
• Men may require some shaving of chest hair. The technician will do this at your appointment if required.

What is an exercise stress test?

An exercise test or stress test measures your exercise capacity, helping to diagnose exercise-related symptoms, such as chest pain, and indicating treatment. Stress tests are useful for indicating the presence or risk of coronary artery disease, such as cardiac ischaemia. It involves exercising on a stationary bike or treadmill in the presence of a doctor and technician while your ECG and blood pressure are monitored continuously.

What happens during a stress test?

You will be asked to undress to the waist (bra can be left on for ladies) and a blood pressure cuff and ECG electrodes attached. The exercise will start at a low, gentle level and, while monitoring your blood pressure and heart rate, the intensity will gradually increase until the doctor feels it is appropriate to stop. Reasons for stopping exercise include excessive breathlessness or fatigue, chest or other pain, ECG and blood pressure abnormalities, or having reached your maximum predicted effort. Your recovery will then be monitored for a short time.

How long will an exercise test take?

Approximately 40 minutes, with the exercise component lasting up to around 20 minutes.

How to prepare for exercise stress testing:

• Unless specifically told, please continue to take all your usual medications prior to test.
• Bring a list of current medication and your referral.
• Do not eat for 2 hours prior to test.
• Wear a comfortable two-piece outfit and rubber soled shoes suitable for exercise.
• You will be asked to undress to the waist (ladies may leave their bra on) as electrodes are attached to the chest. Men may require some chest hair to be shaved – this will be done at the appointment if necessary.

What is a thallium exercise test?

An exercise thallium scan involves includes an injection of a safe weak radioactive material (thallium or sestamibi) into a vein and two scans of the heart: one immediately following the injection and one after several hours. Used where the ECG alone may not provide diagnostic information. Instructions will be mailed to you once appointment is confirmed.

What happens during a thallium exercise test?

You will be injected with thallium or sestamibi. Adhesive electrodes will be applied and connected to an electrocardiogram (ECG) machine and blood pressure monitor, and then asked to walk on a treadmill (or cycle on a stationary bike). As your heart rate, heart rhythm, and blood pressure are monitored, the speed and incline of the treadmill (or resistance of the bike) will be gradually increased until you feel you can’t exercise anymore.

A doctor and nurse will be present, and the test may be stopped if there are any concerning changes to your ECG or blood pressure or other concerning symptoms.

After the test, a gamma camera is used to capture images of the heart for 30 minutes. This is followed by a break, and further imaging later in the day.

If you are unable to exercise at all, your referring doctor may instead request a dipyridamole thallium scan. You will be injected with dipyridamole, which will physiologically simulate exercise – your heart will beat harder and faster, just as if you were exercising. You may experience some minor side effects such as flushing or nausea.

How do I prepare for thallium exercise testing?

Wear shoes and clothing that is comfortable/appropriate for exercising, such as sneakers, shorts and a t-shirt. You will be asked to remove your shirt to facilitate use of ECG and blood pressure monitoring. Female patients may wear a bra/sports bra.

Thallium/sestamibi exercise tests at Western Cardiology are conducted in conjunction with SKG Radiology, and you will receive bills from both providers. Detailed instructions for the procedure will be provided ahead of time. You will need to:

• fast and avoid caffeine for 24 hours prior to the test
• avoid any eating, drinking, chewing, or smoking for 4 hours prior to the test, and
• take all your regular medications (unless instructed by your doctor).

How long does thallium exercise testing take?

This test is done in stages over a number of hours at SKG and Western Cardiology. You will be able to leave the hospital between the first and second imaging sessions.

What is a Holter monitor?

A Holter monitor is a small wearable/portable electrocardiogram (ECG) device used to record the heart rate and rhythm over 24 hour period or longer. Holter monitors are used to assess for arrhythmias, check the effect of medications, identify problems with a pacemaker, and for surveillance/observation of changes over time.

What does Holter monitoring involve?

You will be asked to remove your shirt. A cardiac technician attaches adhesive electrodes on the chest – these connect to a small recording unit worn on a belt or over the shoulder. You will be asked to keep a diary of your activities and any symptoms experienced during the 24 hours. You ought to go about your usual activities, including exercise, but will not be able to bathe/shower/swim. You will return to the office with the device at the end of the monitoring period, and the rhythm tracings will be interpreted by a cardiologist and a report sent to your referring doctor.

How to prepare for a Holter monitor:

• Bathe/shower in the morning – you will not be able to do so while wearing the Holter monitor.
• Wear a two-piece outfit – you will need to remove your shirt to attach the electrodes.
• Men may require some shaving of chest hair.

Please ensure that you are available to return the monitor along with your symptom & activity diary to us at the end of the 24 hour period. This will usually just take a few minutes; the technician will give further instructions for return at the time of fitting the monitor. 

What is a stress echocardiogram?

The stress echocardiogram – commonly known as “stress echo” – combines standard transthoracic echocardiography with exercise testing, taking images of the heart to assess for functional abnormalities before and after exercise. This test is used when the normal exercise test alone may not provide adequate information or when additional information about heart function is required. Usually a stress echocardiogram is ordered to assess coronary artery disease.

What happens during a stress echo?

At the beginning of the test you will be connected to a 12 lead ECG and your blood pressure taken. A sonographer will ask you to lie on a bed and perform an echocardiogram study, using a small probe covered in water-based gel to view ultrasound images of your heart. You will then be asked to walk on a treadmill or cycle on a stationary bike, with the intensity of exercise (speed and incline/resistance) increasing gradually.

A doctor and cardiac sonographer will be present for the duration of the test, monitoring your blood pressure and ECG and looking out for concerning symptoms, such as shortness of breath, fatigue, and chest pain. The test will be stopped if you experience adverse symptoms or reach your target heart rate. Immediately on ceasing exercise the sonographer will do a second echocardiogram study of your heart while the rate is still elevated post-exercise, and your heart beat and blood pressure monitored for a brief recovery period.

How to prepare for a stress echo?

• Fast for 2 hours prior to the test.
• Wear comfortable two-piece clothing (such as shorts and t-shirt) that is suitable for exercising and rubber-soled shoes.
• Please let us know at the time of booking if you have mobility problems that inhibit your use of a treadmill or bicycle.
• Bring a list of current medications and your referral.