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.
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.
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.
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.
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.
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.
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
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
angioplasty) and the insertion of a stent (a stiff cylindrical tiny ‘piping’
to keep the blockage open) after
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
Reducing the risk of heart attack
means making healthy lifestyle
choices. These include:
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
National Heart Centre SingaporeTel: 6704 2000
Subscribe to our mailing list to get the updates to your inbox