| Atherosclerosis
is a gradual pocess in which plaques (collections) of cholesterol are deposited
in the walls of arteries. Cholesterol plaques cause hardening of the arterial
walls and narrowing of the inner channel (lumen) of the artery. Arteries that
are narrowed by atherosclerosis cannot deliver enough blood to maintain normal
function of the parts of the body they supply. For example, atherosclerosis of
the arteries in the legs causes reduced blood flow to the legs. Reduced blood
flow to the legs can lead to pain in the legs while walking or exercising, leg
ulcers, or a delay in the healing of wounds to the legs. Atherosclerosis of the
arteries that furnish blood to the brain can lead to vascular dementia (mental
deterioration due to gradual death of brain tissue over many years) or stroke
(sudden death of brain tissue).
In many people,
atherosclerosis can remain silent (causing no symptoms or health problems) for
years or decades. Atherosclerosis can begin as early as the teenage years, but
symptoms or health problems usually do not arise until later in adulthood when
the arterial narrowing becomes severe. Smoking cigarettes, high blood pressure,
elevated cholesterol, and diabetes mellitus can accelerate atherosclerosis and
lead to the earlier onset of symptoms and complications, particularly in those
people who have a family history of early atherosclerosis.
Coronary
atherosclerosis (or coronary artery disease) refers to the atherosclerosis that
causes hardening and narrowing of the coronary arteries. Diseases caused by the
reduced blood supply to the heart muscle from coronary atherosclerosis are
called coronary heart diseases (CHD). Coronary heart diseases include heart
attacks, sudden unexpected death, chest pain (angina), abnormal heart rhythms,
and heart failure due to weakening of the heart muscle
Atherosclerosis
and angina pectoris
Angina pectoris
(also referred to as angina) is chest pain or pressure that occurs when the
blood and oxygen supply to the heart muscle cannot keep up with the needs of the
muscle. When coronary arteries are narrowed by more than 50 to 70 percent, the
arteries cannot increase the supply of blood to the heart muscle during exercise
or other periods of high demand for oxygen. An insufficient supply of oxygen to
the heart muscle causes angina. Angina that occurs with exercise or exertion is
called exertional angina. In some patients, especially diabetics, the
progressive decrease in blood flow to the heart may occur without any pain or
with just shortness of breath or unusually early fatigue.
Exertional
angina usually feels like a pressure, heaviness, squeezing, or aching across the
chest. This pain may travel to the neck, jaw, arms, back, or even the teeth, and
may be accompanied by shortness of breath, nausea, or a cold sweat. Exertional
angina typically lasts from 1 to 15 minutes and is relieved by rest or by
placing a nitroglycerin tablet under the tongue. Both resting and nitroglycerin
decrease the heart muscle's demand for oxygen, thus relieving angina. Exertional
angina may be the first warning sign of advanced coronary artery disease. Chest
pains that just last a few seconds rarely are due to coronary artery
disease.
Angina also can
occur at rest. Angina at rest more commonly indicates that a coronary artery has
narrowed to such a critical degree that the heart is not receiving enough oxygen
even at rest. Angina at rest infrequently may be due to spasm of a coronary
artery (a condition called Prinzmetal's or variant angina). Unlike a heart
attack, there is no permanent muscle damage with either exertional or rest
angina.New in heart attack?
Greater public
awareness about heart attacks and changes in lifestyle have contributed to a
dramatic reduction in the incidence of heart attacks during the last four
decades. Improved anticoagulant drugs such as hirudin and hirulog, are being
tested and may complement current therapies. The role of the "super aspirins"
(Reopro and Integrilin) is currently being investigated as well. More effective
versions of TPA are being developed. Increasingly, paramedics can do ECGs in the
field, diagnose a heart attack, and take patients directly to hospitals that
have the ability to do PTCA and stenting. This can save time and reduce damage
to the heart. Recent data has shown that lowering blood LDL levels even further
than previously suggested may further decrease the risk of heart attacks.
Research also has shown that inflammation may play a role in the development of
atherosclerosis, and this is an active area of current investigation. There also
is early evidence that with genetic engineering it may be possible to develop a
drug that can be administered to clear plaques from arteries (a "scavenger
molecule").
Heart Attack At
A Glance * A heart attack results when a blood clot completely obstructs a
coronary artery supplying blood to the heart muscle and heart muscle
dies.
* The blood
clot that causes the heart attack usually forms at the site of rupture of an
atherosclerotic, cholesterol plaque on the inner wall of a coronary
artery.
* The most
common symptom of heart attack is chest pain.
* The most
common complications of a heart attack are heart failure, and ventricular
fibrillation.
* The risk
factors for atherosclerosis and heart attack include elevated cholesterol
levels, increased blood pressure, tobacco use, diabetes, male gender and a
family history of heart attacks at an early age.
* Heart
attacks are diagnosed with electrocardiograms and measurement of cardiac enzymes
in blood
* Early
reopening of blocked coronary arteries reduces the amount of damage to the heart
and improves the prognosis for a heart attack.
* Medical
treatment for heart attacks may include anti-platelet, anti-coagulant, and clot
dissolving drugs as well as angiotensin converting enzyme (ACE) inhibitors, beta
blockers and oxygenl
*
Interventional treatment for heart attacks may include coronary angiography with
percutaneous transluminal coronary angioplasty (PTCA), coronary artery stents,
and coronary artery bypass grafting (CABG).
* Patients
suffering a heart attack are hospitalized for several days to detect heart
rhythm disturbances, shortness of breath, and chest pain.
* Further
heart attacks can be prevented by aspirin, beta blockers, ACE inhibitors,
discontinuing smoking, weight reduction, exercise, good control of blood
pressure and diabetes, following a low cholesterol and low saturated fat diet
that is high in omega-3-fatty acids, taking multivitamins with an increased
amount of folic acid, decreasing LDL cholesterol, and increasing HDL
cholesterol. |
