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In this article:
If you have chronic
angina for long enough and don't make the necessary changes
to try to regain your heart
health, you may be at risk for a more serious condition called acute
coronary syndrome, or ACS. ACS is a sudden and severe condition
of the heart that can include unstable
angina, heart attack, and sudden death (also called sudden
cardiac death).
Unstable angina
Unstable angina1
is considered unstable because the pain or discomfort you feel is
worse than at any time over the previous two months, your attacks
have increased in number, or attacks are triggered more easily by
activities that didn't bother you before, including light activities
or rest.
Typically, people with unstable angina have very bad coronary artery disease
(CAD) that has suddenly gotten worse. Doctors now know that unstable
angina occurs when blood flow through the coronary arteries is suddenly
almost totally blocked, severely restricting the amount of oxygen-rich
blood flowing to the heart. This is different from chronic angina,
where the flow of oxygen-rich blood is reduced but not as severely.
The severe and sudden blockage of a coronary artery happens for several reasons.
One may be that those cells in the blood called platelets—which
have a sticky, adhesive quality—have suddenly clumped together
in an artery with other substances such as fats, cholesterol, and
calcium to form a plaque. Or, the wall of the artery may have become
less flexible, possibly due to plaque buildup. This leaves a much
smaller passageway for the blood to travel through. A blood clot
also may have formed in the area.
Unstable angina attacks often last longer than chronic angina attacks. Also,
if your angina is more severe, or begins to occur while you're resting
or using minimal effort, you may be close to having a heart attack.
Angina pain or discomfort that continues despite rest, or without
relief from short-acting nitroglycerin, is usually considered a
medical emergency. Seek help immediately.
Heart attacks
A heart attack also is called a myocardial infarction (MI), or
acute myocardial infarction (AMI). Heart attacks are another part
of ACS. When a section of your heart stops getting oxygen-rich blood
via one of the coronary arteries, a heart attack may occur. A blockage
in the artery is usually due to the breakup of a fatty plaque. Materials
in the plaque can cause a blood clot to form in the artery, which
can completely block blood flow. This leads to severe damage in
the heart, causing a section of the heart muscle to die. And it
happens quickly: within a matter of seconds, your heart can stop
working normally.2
About 1.1 million Americans suffer a heart attack each year.2 Of
these, about one-quarter will die within an hour, even before reaching
the hospital.3 If your doctor has told you you're at risk for having
a heart attack, be sure you know what to expect and how to prepare
for this emergency. See You
and Your Family for useful information.
Sudden death
Not everyone who has a heart attack will die. Yet, about 300,000 people die
suddenly from cardiac disease every year in the United States. About
one-half of CAD deaths are sudden and unexpected.4 In many, death
is the only sign that heart disease is even present. Some may have
had a heart attack in the past without even knowing it (a condition
known as a silent MI).
There are different causes of sudden death. Heart muscle damaged by high blood
pressure or CAD doesn't work well. For one, the pumping action of
the heart is hindered; it can't pump blood out as well as before.
This makes the heart work much harder than a normal, undamaged heart.
Abnormal heart rhythms—called arrhythmias—are another possible cause
of sudden death. As long as the heart muscle is healthy, electrical
signals keep it beating in its regular rhythm. A damaged muscle
also means a malfunctioning electrical system. Just as in a house,
bad wiring can lead to an electrical short. If the heart's electrical
system shorts out, the heart beats wildly—too fast for the heart
to fill with enough blood to send to the body—and blood pressure
begins to drop. When the brain, heart, and other organs aren't getting
enough oxygen-rich blood, they begin to seriously malfunction. Once
this happens, and if emergency treatment isn't received, death can
follow.
Another related problem: heart failure
Many people who have had ACS are heart attack survivors. But if the heart muscle
is seriously damaged, some of these survivors may eventually develop
heart failure, sometimes called congestive heart failure (CHF).
Heart failure means your heart can't pump with the same strength and force
as it could before the heart attack. Your heart will work very hard
to try to make up for the lost muscle strength. Yet it may still
have problems filling the chambers with enough blood, or with sending
enough blood to the rest of the body.
Your heart may try to make up for its lost strength by making the muscle bigger
and by beating faster. But eventually, the heart will tire out.
If heart failure gets worse, your other organs won't be getting
enough blood to work well either. You may find it difficult to breathe
and have to cough a lot. You also can have swelling in the lower
legs. Plus, heart failure can make you so tired that you may not
be able to do even the easiest daily activity.
Making lifestyle changes early could help avoid unwanted heart problems from
worsening and make living better, even with angina and/or heart
failure. See Managing Angina and CAD for more information.
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Cooking with canola or olive oil is a heart-healthy
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Sources
1. Gersh, B.J., E. Braunwald,
and J.D. Rutherford. "Chronic Coronary Artery Disease." Heart Disease:
A Textbook of Cardiovascular Medicine. 5th ed., Ed. Eugene Braunwald.
Philadelphia: W.B. Saunders, 1997. 1331-1339.
2. American Heart Association.
2002 Heart and Stroke Statistical Update. 2001.
http://www.americanheart.org/downloadable/heart
/10148328094661013190990123HS_State_02.pdf
3. Alexander, R.W., C.M. Prat,
et al. "Diagnosis and management of patients with acute myocardial
infarction." Hurst's The Heart. 10th ed., Ed. V. Fuster, et al.
New York: McGraw-Hill, 2001. 1276.
4. Myerburg, R.J., A. Castellanos.
"Cardiac Arrest and Sudden Cardiac Death." Heart Disease: A Textbook
of Cardiovascular Medicine. 5th ed., Ed. Eugene Braunwald. Philadelphia:
W.B. Saunders, 1997. 742-779.
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