There are only a limited number of hospitals in Singapore who operate a full facility cardiac rescue unit, commonly referred to as a full cardiac suite. Apart from being able to run investigations like those listed below, the facility will also have a cardiologist on 24-hour duty. He will be able to perform the required surgery, be it interventional or coronary artery bypass graft (CABG) surgery to alleviate coronary heart disease symptoms.

If you have risk factors for coronary artery disease, your doctor may advise diagnostic testing, even if you present no symptoms of narrowed arteries. The following diagnostic techniques are available within the Parkway Group of facilities including Mount Elizabeth Hospital, Gleneagles Hospital as well as our various cardiac specialists' clinics.

AN EXAMINATION FOR CORONARY ARTERY DISEASE MAY INCLUDE THE FOLLOWING TESTS:

Electrocardiogram (ECG)
This is a simple test in which stick-on patches with wires (electrodes) are attached to your skin to measure electrical impulses given off by your heart. This test can show evidence of a previous heart attack or one that's in progress. It can also yield other useful information, such as rhythm and the status of the electrical system in your heart.

ECG readings taken continuously over a period of 24 hours or longer may help detect silent ischemia. This technique is called ambulatory electrocardiography monitoring, or Holter monitoring.

Electrodes attached to your chest are connected to a portable monitor about the size of a paperback book - that attaches to your belt or is carried by a shoulder strap. You wear the monitor for 24 hours as you go about your normal activities. Abnormalities recorded may show evidence of inadequate blood supply to your heart or it may detect abnormal heart rhythms called arrhythmias.

Stress Test
Stress tests help measure how well your heart muscle functions and whether it's getting adequate blood supply. They may be used to evaluate symptoms such as chest pain or shortness of breath during exertion.

Or if you have significant risk factors for coronary artery disease - even if you have no symptoms - a stress test can be used as a screening tool.

There are several kinds of stress tests and they can be combined with imaging tests to visualise your heart under "stress". The most common tests include:

§ Treadmill exercise stress test. You walk on a treadmill while an ECG records your heart's response to an increasing workload. The test is usually used for screening or as a first-line evaluation of symptoms. It is generally safe and is useful for detecting significant coronary artery disease. For those who cannot walk on a treadmill, other forms of exercise, such as pedalling a stationary bicycle or doing arm exercises, are sometimes used.

§ Non-exercise (pharmacologic) stress tests. These tests are for people who are not able to exercise, such as those with arthritis or leg problems. A medication, such as adenosine, dipyridamole or dobutamine, is used to "stress" your heart and mimic the state that one would be in during exercise.

§ Stress tests with imaging. Imaging tests provide further information by generating pictures of your heart during and after exercise or pharmacologic stress. They may be used alone or can help clarify results of previous stress tests that were not combined with imaging.

CT (Computed Tomography)
CT combines X-ray technology and computers to produce cross-sectional images of the heart. This process enables physicians to obtain an accurate diagnosis through "non-invasive" imaging. The Multi-Slice CT is the world's first scanner to help doctors simultaneously capture multiple images of a patient's anatomy, while increasing image clarity for diagnosis in brain, chest, abdomen, pelvis, spine, sinus and vascular studies

This new method is useful as a screening modality for those people who are at risk of having blockages but have not developed complications; it gives an approximate picture of the blockages in the arteries as well as the details like calcification of the blockages.

CT based angiography gives better information about the coronary arteries than what is provided by other non invasive procedures like stress tests. Approximately 10 to 20% of patients undergoing coronary angiography do not have significant coronary artery disease.

With the multi-slice CT scan angiography, patients can now be spared of undergoing an invasive procedure like catheter based angiography.

(This article first appeared in Parkway Medicine, April 2002)