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Heart Attack and Ischaemic Heart Disease

​Heart Attack and Ischaemic Heart Disease: What is it

Your heart pumps blood 72 times each minute, 100,000 times each day, making sure all parts of the body are supplied with blood. How does the heart itself receive blood? The coronary arteries, coming straight from the main artery or aorta, supply blood to the heart.

What is coronary artery disease?

Ischaemic heart disease, also called coronary artery disease, is what the layman refers to as having ‘heart problem’. The coronary arteries are narrowed, causing chest discomfort, breathlessness and tiredness because of inadequate blood flow to the heart muscle. ‘Ischaemic’ means ‘inadequate blood flow’.

These narrowings occur because the lining of the coronary vessels become accumulated with cholesterol and fat in layers called atherosclerotic plaques. In Singapore, heart disease and cancer are the top two causes of death.

What is a heart attack?

A heart attack occurs in someone with ischaemic heart disease when any of these three arteries get suddenly (acutely) blocked. This may happen because a blood clot suddenly forms over the narrowed portion, or a fatfilled plaque bursts or ruptures. The heart muscle (myocardium) that has its blood supply interrupted will die (‘infarction’) if flow is not restored. A heart attack is also called acute myocardial infarction.

Consequences of a heart attack
A severe blockage will result in immediate death. Heart attacks are the leading cause of sudden death for both men and women worldwide. Less severe blockage will weaken the heart and result in heart failure later on, where the person feels breathless as the heart cannot pump enough for the body’s needs. Irregular or slow heart rates can also happen.

Signs and symptoms of a heart attack

Chest pain or discomfort is the most common symptom (angina). Discomfort can occur in the centre or left side of the chest, may go up to the neck, jaw or left arm. The discomfort can feel like uncomfortable pressure, squeezing, fullness or pain. It can be mild or severe.

It can be associated with shortness of breath, nausea, vomiting, palpitations, sweating and anxiety. Women may experience fewer typical symptoms than men and approximately one quarter of all heart attacks are silent, without chest pain or other symptoms.

Causes of heart attacks and ischaemic heart disease

The four main preventable causes of plaque formation are smoking, diabetes, hypertension and hyperlipidaemia (high blood cholesterol and fat). Other contributing factors are obesity, lack of exercise, stress, and increasing age.

Men older than 45 years and women older than 55 years after menopause are at higher risk. Your risk increases if your father or brother had a heart attack before 55 years of age, or if your mother or a sister had a heart attack before 65 years of age.

Diagnosis of heart attacks and ischaemic heart disease

An electrocardiogram (ECG) records the electrical activity of the heart, and blood cardiac enzyme levels detect heart muscle damage. Coronary angiography shows exactly where the blockage is. It requires the insertion of a fine tube (catheter) via an artery in the leg directly into the coronary vessels. Dye is injected into each of them to outline where the blockage is as viewed by an x-ray examination.

Treatment of heart attacks and ischaemic heart disease

If a heart attack is suspected, the person must be rested, kept calm, propped up and brought to a hospital immediately. Initial measures will be to administer oxygen and relieve pain by nitroglycerin placed under the tongue, via a skin patch or injection of morphine in severe cases. Aspirin is used to prevent more blood clots and drugs called beta-blockers to slow down the heart, are also used. The heart beat is monitored for irregularities.

If blood flow can be restored within six hours, the myocardium can be saved from totally dying. If a person arrives at hospital on time, doctors may attempt to open up the blockage through a catheter by a balloon inflated at the site of the blockage (PTCApercutaneus transluminal coronary angioplasty) and the insertion of a stent (a stiff cylindrical tiny ‘piping’ to keep the blockage open) after ballooning.

Coronary artery bypass grafting may be offered where there are multiple blockages. This is a heart operation where other blood vessels such as veins from the leg are removed and sewn across the blocked portions, thereby ‘bypassing’ the blockages.

Can PTCA and CABG be done early to prevent a patient with ischaemic heart disease from developing a heart attack?

Both PTCA and CABG can be done where there are significant blockages but a heart attack has not occurred yet. This in fact would be better. People with risk factors and symptoms of chest pain and breathlessness may benefit from a cardiology referral for coronary angiography or other tests to look for blockages.

Prevention of heart attacks and ischaemic heart disease

Reducing the risk of heart attack means making healthy lifestyle choices. These include:

  • A low-fat diet rich in fruits and vegetables, lower in salt
  • Losing weight and cutting back on calories if you’re obese
  • Quitting smoking
  • Exercise to improve heart fitness.
    Ask your doctor what kinds of physical activity are safe for you.

The best prevention is to prevent risk factors even before they occur. However, not everyone has the opportunity to do this early enough. If hypertension, diabetes and hyperlipidaemia are already present, these conditions must be well treated.

If significant risk factors are present, regular screening e.g. annually for heart disease may need to be done. These include ECG, treadmill test (ECG while exercising), echocardiogram (ultrasound of the beating heart), and in high-risk cases, CT ( computer) scan of the heart that shows up blockages.

If you have risk factors and symptoms such as chest pain, breathlessness and sweatiness on exertion, consult a doctor immediately to be assessed for ischaemic heart disease. Blockages may already be present. If detected early, PTCA/CABG done before a heart attack occurs will produce a far better outcome.

Please consult your Family Doctor if you have any concerns about your health.

Specialist services available at the following SingHealth institutions:

National Heart Centre Singapore
Tel: 6704 2000