Non-invasive Tests

A wide range of tests are available to diagnose the different forms and stages of heart disease. In general, a doctor will start by taking the patient’s medical history and conducting a physical examination. Depending on the findings, a series of non-invasive and/or invasive tests may then be used to pinpoint the specific nature and severity of the heart condition which the patient is suffering from.

Non-invasive Tests:

Chest X-ray
A conventional X-ray of the chest yields basic information about the size and shape of the patient’s heart, blood vessels, and lungs.

Electrocardiography / Electrocardiogram
Electrocardiography is a method of measuring the electrical impulses in the heart. This is usually done by placing 12 electrodes on the patient’s chest and limbs. The electrodes are then connected to a machine which records the rhythm, frequency of beats, and electrical conduction of the patient’s heart. The test takes about 10 minutes to complete, and the printed result is known as an electrocardiogram, or “ECG” for short.

It contains information about:
– The patient’s heart rhythm and heart rate
– Any previous or on-going heart attacks
– The thickening of the heart muscle and enlargement of the chambers of the heart, if any;
– Whether or not blood supply to the patient’s heart is poor.

Together, such data provides clues to the likely reasons for the patient’s cardiac condition as well as the appropriate course of treatment.

Holter Monitoring
A variation on conventional electrocardiography is Holter monitoring. This is ECG monitoring done over time, usually in the course of a normal day’s activities. For this form of electrocardiography, the patient carries an ECG monitor in a small satchel worn on his body so that measurements may be taken of any spontaneous periods of chest pains and/or irregular heart rhythms which he may experience during the test period.

Exercise Stress Test
Sometimes, an ECG is done while the patient is exercising. Typically, the patient is asked to run on a treadmill while wearing the usual ECG electrodes. Recordings are taken simultaneously at 3-minute intervals, with the speed and elevation of the treadmill being gradually increased in the course of the test until the patient either reaches his target exercise heart rate or develops chest pains and indicates that he is unable to continue with the test. An exercise ECG is most helpful for a patient who experiences chest pains only upon physical exertion, but who otherwise has normal ECG results when at rest. It allows doctors to assess the amount of physical activity which such a patient can undertake comfortably (also known as his “exercise tolerance”). It also sheds light on how well his heart responds to the stress arising naturally from exercise.

Echocardiography is a technique which uses sound waves (ultrasound) to evaluate the internal structure, movement, chambers, and valves of the patient’s heart. It is also useful in the diagnosis of heart attacks and coronary heart disease. Spectral Doppler echocardiography is a special form of echocardiography which analyses the speed and direction of blood flow in the patient’s cardiovascular system. It helps to highlight any disorders of the heart valves, coronary muscles, and coronary arteries which the patient might have.

Computed Tomography (CT) scan
Also known as a CAT scan, a CT scan provides cross-sectional images of the patient’s chest, including his heart and the surrounding blood vessels. It is useful in the diagnosis of cardiac tumours, aortic disease, as well as pericardial disease (disease of the pericardium).

Magnetic Resonance Imaging (MRI)
In MRI, powerful magnets are used to produce three-dimensional, high-resolution images of the patient’s internal body structures. Such images, which include detailed information about the heart muscle, are vital in the detection of damage caused by a heart attack, diseases of the coronary arteries, and other cardiovascular defects.