Diagnostic Services

Cardiac Case Studies

Cardiac Case Studies

Echo

An apical 4 chamber view of the heart
An apical 4 chamber view of the heart.

In this image, the left side of the heart is displayed to the right of the image. The ventricles (the main squeezing chambers) are at the top and the atria are below. There is a valve displayed on each side, between the atrium and ventricle. These ensure blood only moves in one direction through the heart.

A Colour Flow M-mode image
A Colour Flow M-mode image.

The Echo machine combines two separate imaging techniques to create this image. It displays one of the features used to determine the diastolic (filling) function of the left ventricle.

Tissue Doppler Imaging
Tissue Doppler Imaging.

The principle behind creating this image is similar to the function of a speed camera determining whether a motorist is travelling too fast. This image uses heart muscle movement to assess both systolic (squeezing) function and diastolic (filling) function of the left ventricle. Doppler may also be used to view blood flow within the heart and large blood vessels.

Contrast Study Image
Contrast Study

Determination of shunting (movement of blood between two chambers of the heart) can be challenging by ultrasound alone. This technique utilises agitated saline to generate microbubbles which move down the blood stream and into the heart. Because air is a very good reflector of ultrasound the right side of the heart becomes white with contrast. If shunting is present, bubbles will appear on the left side of the heart. The remaining contrast is pumped to the lungs and the air in the bubbles is breathed out.

Stress Echo

Stress Echocardiogram Image
Stress Echocardiogram

The coronary arteries themselves can not be observed with this technique. Instead the operator interrogates for inadequate blood flow to the heart muscle due to a significant narrowing in one of the arteries. At high level exercise the heart muscle will not respond normally if the supply is inadequate. The machine displays images of the heart at rest on the left and post exercise images on the right. A direct comparison is then made on several views of the heart to determine the diagnosis.

ECG

A standard ECG
A standard ECG

From the 10 electrodes (sticky dots) placed on the skin, 12 separate tracings are displayed. The size and direction of electrical impulses through the heart can be observed. The machine will generate an interpretation, although a final judgement by a cardiologist is necessary. In this instance the interpretation is correct. This is a normal ECG.

Stress Test

A standard Bruce Protocol stress test
A standard Bruce Protocol stress test

ECG recordings are made continuously during and after exercise. This image depicts a positive test (identifies a problem). The patient experienced shortness of breath and chest heaviness during exercise, both of which can be features of angina. The inferior leads (II, III and aVF) and lateral leads (V4, V5 and V6) all show ST depression, a positive marker for is chaemeia (inadequate blood supply to heart muscle). Both the patient’s symptoms and the ECG tracings support the diagnosis.

Holter

A Holter report example
A Holter report example

This is an example of a report and some of the data supplied to your doctor about a patient’s heart rhythm.

Two selected ECG tracings from a Holter report
Two selected ECG tracings from a Holter report

This is an example of the ECG tracings stored by the monitor. The top image depicts a form of heart block where conduction has started in the atria (top chambers of the heart) and has not progressed to the ventricles (bottom chambers of the heart). The bottom tracing displays a heart beat with electrical conduction originating in the ventricle. It occurs earlier than a normal beat and there is a brief pause after. Some people are aware of these and report them as palpitations.

BP

Blood pressure profile over 24 hours
Blood pressure profile over 24 hours

This image displays the recording made over 24 hours by an Ambulatory Blood Pressure monitor. The systolic and diastolic blood pressure readings are displayed in blue. The normal range should be between the two white lines. This indicates that the medication taken by the patient partially controls blood pressure during the day, with very poor control during the night.

The statistical results report made from the recordings
The statistical results report made from the recordings

This is a detailed layout of the maximum and minimum recordings and a percentage of the time blood pressures are above normal.

Histograms of frequency distribution in the final report
Histograms of frequency distribution in the final report

This is an example of the typical data a referring doctor will receive. It displays the percentage of recorded values for systolic and diastolic blood pressures. This can be displayed for the full 24 hours, day time only or night time only recordings.

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