Download Normal Coronary Artery Function Normal Heart Function

(Cross-sectional view)
Normal
coronary artery
Left coronary
artery
Heart Facts
• The heart beats
continuously, resting for
only a fraction of a
second between beats.
• Of all the blood pumped
by the heart, 5 – 7% is
needed by the heart itself.
Right coronary
artery
Normal Heart Function
Normal active
heart muscle
Enlarged view
(opposite page)
The heart is an active muscle that pumps a continuous supply of oxygen-rich blood through
arteries to all parts of your body. The coronary arteries surrounding the heart deliver oxygen-rich
blood to the heart itself. Each coronary artery supplies a different part of the heart.
Normal Coronary Artery Function
During exercise or periods of emotional stress, the heart beats faster and thus needs more oxygen.
Healthy coronary arteries can easily deliver the extra blood needed for the heart’s increased oxygen
demand.
Normal
Atherosclerosis, or
“hardening of the arteries”
Normal
Carotid artery
Plaque
(fatty
deposits)
Coronary
arteries
Atherosclerosis is a common disease in which
arteries (e.g. heart, brain, and legs) become
narrowed due to the gradual formation of
plaque inside the artery walls. Plaque
formation may be caused by high levels of
fat and cholesterol in the bloodstream.
Over time, the buildup of plaque
gradually reduces oxygen-rich blood flow
in the arteries. A crack in the plaque can also cause
small cells in the bloodstream called platelets
to clump together on or near the plaque and form
a blood clot. A blood clot may block the flow of
oxygen-rich blood in the artery and causes serious
health problems, including heart attack and stroke.
Plaque
buildup
Narrowing
of artery
Ruptured
artery
Area at risk
Leg arteries
Coronary Artery Disease
A person with atherosclerosis is at increased risk for both heart attack and stroke.
Coronary artery disease is a condition in which plaque gradually builds up in the cells lining
the wall of a coronary artery (i.e., atherosclerosis of the coronary arteries). Over time, plaque
buildup can obstruct blood flow to the heart muscle itself, causing heart damage.
Atherosclerosis
(Cross-sectional view)
Blood clot
Diagnostic Tests
Common Emergency Signs and
Symptoms of a Heart Attack
These tests are performed
to determine whether a
heart attack occurred.
Plaque
buildup
• Electrocardiogram (ECG)
• Echocardiogram
• Blood tests
If you experience one or more
of the following complaints, seek
medical assistance immediately:
• Intense, continuing chest pain
(“heavy pressure” or “tightness”)
• Pain that extends to the left shoulder
and arm, back, and even teeth and jaw
• Continuing pain in upper abdomen
• Shortness of breath
• Fainting spell
• Nausea, vomiting, fainting, and/or
profuse sweating may also occur.
Damaged muscle
begins to repair
Scar tissue
forms
Heart muscle
begins to die
Heart Attack
If a blood clot or plaque suddenly and severely restricts or cuts off blood flow in any of the coronary
arteries, the area of heart muscle supplied by that artery begins to die. This death of heart muscle is
known as a myocardial infarction or “heart attack.” A heart attack is a medical emergency.
A person who has had a heart attack is at three to four times greater risk of having a stroke.
Heart Attack Recovery
If doctors begin treatment soon after a heart attack, they may be able to limit the extent of
tissue damage to the area around the affected heart muscle. If prompt treatment restores adequate
blood flow soon after a heart attack, the damaged but viable heart muscle begins to heal.
However, dead heart muscle is replaced with scar tissue, which does not function normally.
Heart Attack
Cardiac Procedures
Treatment for a heart attack may begin with
medicines (thrombolytic agents) to help dissolve the
blood clot that is blocking blood flow in the coronary
artery. Coronary angioplasty or coronary artery bypass surgery
may also be performed to help restore blood flow.
Coronary Artery Bypass Surgery
Coronary artery bypass surgery is performed to
reroute, or “bypass,” blood flow around the clogged
coronary artery.
Obstructed area
Coronary Angioplasty
Balloon angioplasty is an intervention to widen
the narrowed arteries of the heart. The interventional
cardiologist threads a balloon-tipped catheter into
the obstructed artery and inflates it, flattening the
plaque against the arterial wall.
Balloon catheter
in coronary artery
Balloon
catheter
inserted
Balloon is
inflated,
compressing
plaque
Following balloon angioplasty, a coronary stent (expandable metal tube) is often delivered to
the newly dilated site. The stent is expanded and left in place to hold the artery open.
Stent
positioned
Stent
expanded
to keep
artery open
Stent in
place
Bypass
Bypass
Site of
blockage
Clogged artery
bypassed
The surgeon removes a section of blood vessel from another part of your body and attaches it
between the aorta (the major artery from the heart) and the coronary artery below the
blockage. An artery may also be detached from your chest wall and the open end attached
to the coronary artery below the blockage.
Intervention
Guidelines for Reducing
Your Risk of Heart Attack
You can help reduce your risk of heart attack
and stroke by making healthy lifestyle changes.
Some Medicines that May Help
Reduce the Risk of Heart Attack
and Stroke
Anti-platelet therapy
• If you smoke, quit! Smoking increases your risk of
atherosclerosis and heart attack.
• Have your blood pressure and cholesterol levels checked
regularly by your doctor.
Platelets are very small blood cells which clump together to help blood clot. Anti-platelet
drugs work by stopping platelets from clumping together. This reduces the chance of blood clots
forming inside hardened blood vessels (a process called thrombosis), which reduces the risk of stroke,
heart attack or death.
Anti-hypertensive therapy
High blood pressure, if not treated, can damage blood vessels in several organs such as the heart, the kidneys, the
brain and the eyes. This may lead to heart attacks, heart or kidney failure, strokes, or blindness.
There are many types of anti-hypertensive therapy which work in different ways to reduce high blood pressure.
• Begin a program of regular exercise such as walking.
Check with your doctor before beginning an exercise program.
• Eat a balanced diet high in fibre and low in cholesterol and
fat. Add more fruits, vegetables, and whole-grain breads and
cereals to your diet.
• Your doctor may prescribe medications to help reduce your
risk of heart attack and stroke. Whether the medication is an
antihypertensive to help control high blood pressure and/or
cholesterol-lowering therapy to reduce your risk of heart
attack and stroke, you should always take your medicine
according to your doctor’s instructions.
Cholesterol lowering therapy
Everyone has cholesterol and triglycerides in their blood. They are needed by the body for many normal functions,
including building cell membranes, making bile acids (which help to digest food) and certain hormones. However,
too much cholesterol of the wrong type and too little of the good type may be a problem.
• Statins: are used in people who have coronary heart disease (CHD) or who are at high risk of CHD (for example,
if they have diabetes, a history of stroke, or other blood vessel disease). Statins work by reducing the amount of
cholesterol made by the liver. Statins reduce the bad cholesterol, raise the good cholesterol and decrease
triglycerides.
• Cholesterol absorption inhibitors: are often used in combination with statins to help with cholesterol reduction.
Cholesterol absorption inhibitors work differently to statins by decreasing the absorption of cholesterol in the small
intestine.
• Other medicines that may also be used to reduce the risk of heart attack and stroke include fibrates, resins, fatty
acids and nicotinic acids. Your doctor will be able to advise you on these therapies.
Prevention