This study provides an almost real-time, three-dimensional image of the heart.
An echocardiogram is an essential diagnostic test providing images of heart movement. Using ultrasound, an echocardiogram delivers information about the shape, size, function, strength and movement of the heart as well as its wall thickness and valve function. It can also provide information about the pulmonary circulation and its pressures, the initial portion of the aorta, and whether there is fluid around the heart (pericardial effusion).
As ultrasound is used to obtain these images, echocardiography is an investigation which does not emit radiation (unlike other tests such as X-ray, CT, etc). Other advantages include that it is pain free and has no side effects.
Echocardiography is the most important test used to study heart valve function and blood circulation through the heart. Depending on the type of echocardiogram performed, it can also determine the size, shape and movement of the heart muscle and provide information on the arteries. At times it is used for the assessment and prognosis of ischaemic heart disease (functional or stress echocardiogram).
In the last few years image quality has significantly improved, partly due to the use of contrast and the ability to study myocardial perfusion with harmonic imaging.
There are two types of echocardiogram, depending on which way we choose to look at the heart:
- Transthoracic: performed through the chest wall.
- Transoesophageal: performed via a probe which is introduced into the oesophagus to allow clearer images. It is useful when certain conditions are suspected.
- Exertion: consists of viewing the heart during exercise.
- For transthoracic echocardiogram: The patient must undress to the waist and lie on their back on the examination couch. Electrodes are then placed to obtain an ECG tracing of the heart. After applying conductive gel, the ultrasound probe is then passed over the chest. The probe is moved across the ribs and sternum to obtain the images. The person performing the echocardiogram may ask the patient to breathe in a certain manner to improve the images.
- In transoesophageal echocardiogram: The back of the patient’s throat is anaesthetised; the probe is then passed down through the patient’s oesophagus to view the heart structures. The procedure takes around 20 minutes. Images are obtained in different planes to provide as much information as possible. Prior to a transoesophageal echocardiogram, the patient must have nothing to eat or drink for a period of time. Beforehand, an explanation of what the procedure involves is important as patient collaboration is essential throughout. It is recommended not to eat or drink anything for 1-2 hours after the procedure.
- Stress echocardiogram: This is performed with the patient lying on a couch, or, using an exercise bike or walking on a treadmill. The patient’s chest is uncovered so that electrodes can be placed to take an ECG tracing and so that a blood pressure cuff can be wrapped around the left arm (to measure blood pressure). Initial images are taken at rest.
Echocardiogram is used to help diagnose several conditions, including:
- Cardiac arrhythmias
- Congenital heart disease
- Valve disease
- Acute myocardial infarction
- Heart failure
Sources: Fundación Española del Corazón. (Spanish Heart Foundation).
September 4, 2019
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