Heart Screening

Heart or cardiovascular disease is one of the leading causes of deaths worldwide. This refers to disorders of the blood vessels supplying the heart and other major parts of the body. A heart screening is able to detect abnormalities and early detection reduces suffering and prevents ailments such as heart failure, stroke and kidney disease.

Early diagnosis means potential lives saved. In many patients, the first symptom of heart disease is heart attack or sudden death, with no preceding chest pain as a warning. Screening tests are used to detect early signs of heart disease before serious complications occur. These tests are designed to detect early illness before a coronary artery becomes completely blocked. Screening tests are of particular importance for patients with high risk factors for heart disease which include a family history of heart problems, an abnormal blood cholesterol profile, cigarette smoking, elevated blood pressure (hypertension), and diabetes mellitus.

Patients have to take the basic tests which include height and weight measurements, blood pressure measurements, blood lipid profile, blood glucose (for diabetes), electrocardiogram (ECG), exercise treadmill and echocardiography.

The Electrocardiogram (ECG) is a test that captures the electrical activity of the heart recorded by electrodes placed on the skin. Treadmill exercise test (TMX) measures the heart’s tolerance for exercise and helps to detect coronary heart disease. The treadmill stress test involves walking and/or running on a treadmill machine while recording the patient’s EC G and blood pressure throughout the test.

Echocardiography test uses ultrasonic energy that is directed over the chest wall to obtain images of the heart. These images show the heart’s position, motion of the walls of the heart, the interior chambers, and blood flow within the chambers of the heart. This can help to determine if the heart valves are functioning properly or if there is an abnormal communication or flow between the chambers or the major blood vessels.

Depending on the patient’s risk factors, more sophisticated and detailed screenings include the following:

• Carotid Ultrasound for evaluation of possible future coronary artery disease: Carotid ultrasound uses high frequency sound waves to image the interiors of the two large arteries in the neck which supply the brain with oxygen-rich blood. Too much plaque in a carotid artery can cause a stroke.
• Multi-slice CT coronary angiography and calcium scoring: Computed Tomography Coronary Angiography (CTA) is a non-invasive heart imaging modality that produces high-resolution, three-dimensional pictures of the heart and large vessels, to determine the presence of fatty or calcium deposits (plaques) in the coronary arteries. Coronary CTA is able to rule out significant narrowing of the major coronary arteries and detect “soft plaque,” in the coronary artery walls that may lead to heart problems in the majority of individuals. The calcium-score screening is a test used to detect calcium deposits found in atherosclerotic plaque in the coronary arteries. It is used to evaluate the risk for future coronary artery disease. The two major factors that doctors are mindful about are radiation and contrast allergy. Doctors will counsel the patients on the associated radiation risks, especially in premenopausal women. However, the latest scanners can drop radiation exposure to below two milli Sieverts and hence the radiation risks will be negligible.
• Cardiac PET (positron emission tomography): patients are evaluated using a PET scanner after intravenously injected with a radioisotope. This test is much faster than traditional myocardial stress test and can be completed within 30 minutes. It is also more accurate with the advantage of assessing individual coronary arteries and coronary flow reserve non-invasively. All these make cardiac PET ideal for intermediate risk patients requiring risk stratification. This includes diabetics, stroke patients, renal impaired patients, patients with implants and post revascularisation patients (stents, CA BG).

The Health Promotion Board, Singapore recommends that every adult aged 18 years and above should go for screening of cardiovascular risk factors. More importantly, patients with risk factors for heart disease should go for regular screening. Individuals aged 18 years and above should be screened for obesity and high blood pressure. Individuals aged 40 years and above should have proper heart screening. However, heart screening is indicated in younger people if they have risk factors or those competing in athletic sports.