Procedures

Procedures Performed

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Transthoracic echocardiography (TTE)

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Complex TTE (bubble and contrast imaging)
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Stress Echocardiography (Treadmill exercise and Dobutamine)
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Trans-oesophageal echocardiography (TOE)
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Cardiac CT Scan

Transthoracic echocardiogram (TTE)

An echocardiogram (also known as an echo) is an ultrasound scan of the heart.

It is the same technique that is used on pregnant women in order to assess the baby in the womb. It is performed either by a consultant or a specialist member of the team (a cardiac physiologist) and involves pressing a probe on different areas on the front of the chest in order take images of the heart. It is very safe and does not use the use of any x-rays.

It allows for a very detailed view of all the structures in and around the heart, including measurements of the heart chambers, evaluation of the heart valves and assessment of the heart pump function.

It provides essential information about the heart structure and is a very commonly used test to screen for many underlying heart conditions.

 

Some more complex scans can also be performed using this technique:

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Bubble echo : a small cannula (plastic tube) is put into a vein and salt water is mixed with small amount of air and is injected. This test is used to look for any holes or abnormal connections in and around the heart

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Contrast echo : a small cannula is put into a vein and a contrast agent (dye) is injected into the vein. This allows clearer assessment of the heart to be made particularly if the images are poor or if assessments of blood clots within the heart are required. This dye is different from the dyes used in X-rays and CT scanners; it does not contain iodine, does not affect kidney function and is very short acting. The risk of any allergic reaction to the dye is very low and is estimated at less than 1 in 10,000.

Stress echocardiogram

A stress echocardiogram is a specialised form of echo which involves assessment of the heart dynamically as opposed just at rest. Typically this test is used in the investigation of chest pain or breathlessness to see if there is an underlying issue with the arteries that supply blood to the heart.

Patients undergo stress usually by exercising on a treadmill in order to raise the heart rate and potentially recreate their symptoms. The treadmill exercise allows for an accurate measure of an individual’s ability to exercise, assessment of heart rate and blood pressure response and continuous monitoring of their ECG (heart tracing) during exercise.

An echo is performed before and immediately after exercise and the 2 sets of images are compared to look for any differences. Whilst the arteries themselves are not seen, any effect of any significant narrowing arteries can be seen by changes in heart function. Contrast agents (dyes) are commonly used to allow for the accurate assessment of any change in heart function.

In some patients, a drug is used in order to increase the heart rate. This is started at a low dose and the drug gradually increased until the heart rate reaches the required level. This is primarily used in patients who are physically unable to exercise on the treadmill or in some specialist investigations to assess the pump function if there has been an old heart attack or in assessments of heart valve disease.

Transoesophageal echocardiogram (TOE)

A transoesophageal echocardiogram is a more advanced type of echocardiogram. Similar to a standard echo it still involves taking pictures of the heart using ultrasound. Unlike a normal echo however it is not done on the front of the chest. A small probe is passed through the mouth and positioned in the food pipe which sits directly behind the heart. Very detailed images of the heart can be then obtained.

The procedure is commonly used in the assessment of heart valve disease. This is particularly done if any intervention on the valve is being considered or if the imaging on a normal echocardiogram is of insufficient quality to assess the severity of the valve disease.

The procedure is performed with a local anaesthetic spray to the back of the throat. Given its invasive nature it is also very commonly performed under sedation. Whilst this is not a full general anaesthetic, a sedative drug is given through a drip in the arm. Close monitoring of heart rate, blood pressure and oxygen levels are carried out during the whole of the procedure.

In order for the procedure to be carried out safely patients are asked to not eat or drink anything for 6 hours prior to the procedure being carried out. It is also imperative that someone they trust is able to accompany the patient home and be with them overnight as the sedative drug has the effect of causing forgetfulness potentially up to 24 hours after administration.

Cardiac CT Scan

A cardiac CT (computed tomography) scan uses multiple X-rays form different angles to construct detailed three-dimensional images of the heart and surrounding structures.

New scanner and computer technology allows detailed assessment of the coronary arteries, with the aid of an injection of a colourless dye (contrast) through a small cannula.

The main reason to perform the scan is to look for any calcium or plaque build up in the coronary arteries that supply blood to the heart. It is usually used as appt of the assessment of unexplained chest pain or breathlessness.