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Cardiovascular Disease

VIEWS: 8 PAGES: 5

									A PowerPoint presentation (no narration) containing much of this information is available at the
below web page.

http://facweb.northseattle.edu/troot/HEA150

                               Cardiovascular Disease
Cardiovascular disease is a general term referring to a number of afflictions associated with the
heart ("cardio") and blood vessels (vascular). Heart disease and stroke, then, are forms of
cardiovascular disease. As recognized from the first week's Search & Report, heart disease and
stroke are the first and third most common causes of death in the United States, respectively.
According to the Centers for Disease Control and Prevention (CDC), approximately one fourth
of the American population live with the effects of heart disease or stroke, with the costs of
cardiovascular disease projected to reach $448 billion in 2008 (up from $403 billion projected in
2006). The CDC provides heart disease and stroke maps for the viewer interested in seeing
differences of cardiovascular disease incidence within the United States (O).

Instead of memorizing each of the below cardiovascular terms, trying instead to understand the
relationship among them, or how one condition can lead to another may help with the learning
process.

Hypertension

Hypertension is also known as "high blood pressure." Blood pressure is a measure of the force
blood exerts against the walls of the arteries or arterioles. Systole is the pressure exerted against
the arteries when the heart contracts, diastole is the pressure exerted against the arteries when the
heart relaxes. When the arteries or arterioles are exposed to regular bouts of high pressure, the
pressure can cause damage to these blood vessels, which, in turn, bleed and clot. The vessel's
damaged areas are more likely to accumulate plaque, a substance containing cholesterol,
calcium, fibrin and other materials. The plaque accumulation is known as atherosclerosis (see
below).

The Canadian Hypertension Society features a video about the condition (O).

Arteriosclerosis

Arteriosclerosis is a general term meaning a hardening or thickening of the body's arteries. This
thickening of the arteries may be caused by atherosclerosis (see below), the natural aging
process, or other reasons.

Atherosclersosis

Atherosclerosis is a condition resulting from the buildup of plaque--fatty substances, cellular
waste, calcium, fibrin and other materials--on arterial walls. To view a picture of a normal
coronary artery in the heart (R), travel to the University of Utah's Pathology Laboratory for
Medical Education. To view atherosclerosis in an artery, visit the same site (R). The University
of Utah also shows an image of the "fatty streaks" within an aorta, the vessel responsible for
pumping oxygenated blood from the heart to the rest of the body (R). For those interested in
learning more about atherosclerosis, Peter Libby, MD, has a detailed Quicktime audio
presentation on the "Pathogenesis of the Atherosclerotic Plaque and Acute Coronary Syndromes"
(O--Quicktime software is required).

Atherosclerosis is thought to begin when the inner (endothelial) lining of a blood vessel becomes
damaged. Damage is caused by smoking, high blood pressure (see above), or other reasons. Once
the vessel is damaged, it bleeds and forms a clot. The damaged area accumulates cholesterol,
calcium, and fibrin more easily, leading to the plaque buildup. Howard R. Horn, MD, describes
the role of endothelium to the atherosclerotic process in his Medscape article, "Insulin
Resistance, Diabetes, and Vascular Disease" (O--you may need to subscribe to Medscape in
order to access the article, but doing so is free). Atherosclerosis can occur in virtually any arterial
vessel. When arteries leading to the heart become blocked, blood flow is compromised, which
can trigger angina and myocardial infarction (see terminology, below). Atherosclerosis can also
prevent optimal blood flow in the periphery of the body, such as the legs, in a condition called
peripheral arterial disease. To learn more about peripheral arterial disease, you can watch the
online video at Healthology.com, "Peripheral Arterial Disease: A Disease You Should Know
About" link (O), provided your browser can read streaming media files with software like Real
Media.

Coronary Artery Disease (CAD)

Also known as coronary heart disease, this condition refers to atherosclerosis of the heart's
coronary arteries, those vessels responsible for delivering fresh blood to the muscle. The
atherosclerotic plaque buildup decreases blood flow to the heart muscle, interfering oxygen
demands of the heart. You can see where the coronary arteries are located by viewing an
illustration at the Heart Surgery Forum. (R) University of Utah's Pathology Laboratory shows
images of a coronary artery with approximately 60% occlusion i.e. 60% blocked, and an artery
with even more occlusion (O). Medmovie.com provides an animation with more detailed
information than needed for this course, but the animation may be helpful in better understanding
the atherosclerotic process in coronary arteries (O).

Ischemia

When a body tissue does not receive adequate blood flow, that tissue is said to be ischemic.
Atherosclerosis is one contributor to ischemia. That is, plaque within a blood vessel can
interfere with blood flow to a target tissue. The feeling of ischemia is usually described as
pressure, pain, or similar discomfort. For example, when a blood pressure cuff is attached to the
arm and pumped too high, blood flow to the arm is compromised. The resulting discomfort in the
arm is caused by the ischemia. HealthCenter Online has more information on cardiac ischemia
(O).

Angina
When there is not enough blood flow (ischemia) to the heart, an individual can experience
sensations of pressure or pain in the chest. This pain is referred to as angina, or angina pectoris.
Often, the discomfort may radiate into the arms, back, shoulders and neck, which can mislead the
sufferer into thinking he or she is simply fatigued. For more information on angina, visit the
American Heart Association (O).

Myocardial Infarction

Another name for myocardial infarction is "heart attack." Symptoms of a heart attack include
pain or tightness in the chest, back, arms, and neck; nausea; an erratic pulse; and perspiration due
to a lack of blood flow to the heart. When blood flow within any of the heart's coronary arteries
(the vessels delivering fresh blood to the heart) is impeded, part of the tissue starts to die--a
myocardial infarction. To view cardiac tissue after a myocardial infarction, travel to the
University of Utah's Pathology Laboratory for Medical Education (O--WARNING: this link
contains a sensitive photo, a piece of heart tissue damaged from a heart attack). For more
information on myocardial infarction visit the Heart Problems Clinic (O). Penn State's
Biobehavioral Health Department also has a photo of heart tissue affected by a myocardial
infarction (O).

The American College of Cardiology (ACC) expanded its definition of a heart attack in 2001
(O). The ACC, in conjunction with the European Society of Cardiology, broadened the definition
of heart attack to include individuals who have experienced severe, stable, or unstable angina
AND who have tested positive for a specific amount of cardiac troponin (a heart protein). The
result of the new definition? The number of people diagnosed with a heart attack will increase.
Similarly, in 2007, four international organizations agreed upon new criteria for diagnosing heart
attacks. Prior to 2007, a heart attack diagnosis was made if a patient exhibited two of the three
following criteria: heart attack symptoms (chest pain/pressure, shortness of breath, etc.), an
abnormal electrocardiogram, and a change in certain biomarker levels in the blood. In 2007, the
organizations specifically recognized the protein troponin as the biomarker, since presence of the
substance indicates heart cell damage. As a result of this change, the number of diagnosed heart
attacks will increase.

The HeartCenter Online provides an animation and audio presentation describing coronary artery
disease and heart attack (O--highly recommended but not required).

Arrhythmia

An abnormal heart beat is known as arrhythmia. The abnormal beat can be one that is too fast
(tachycardia), too slow (bradycardia), or simply irregular, usually due to some underlying
disease. For more information on arrhythmias, refer to the American Heart Association. (O) The
heart's electrical system is described in an audiovisual animation at the National Heart Lung and
Blood Institute (R). To see an animation of normal "sinus" heart rhythm, travel to WebMD to
view the animation of sinus rhythm (R). Travel to Healthology and click on the link, "What is
Arrhythmia?" to read or watch a video clip about the condition.(O)
An arrhythmia can be detected through a test called an electrocardiogram (ECG or EKG). The
Heart Problems Clinic features examples of what ECG's look like in the case of tachycardia and
in a premature beat (O--click on "Arrhythmias" to view ECG patterns). In some patients,
pacemakers may be required for specific arrhythmias. Medtronic describes different types of
pacing systems and medical and dental procedures that possibly may interfere with their
pacemakers (O).

Cardiac Arrest

Cardiac arrest is different from heart attack. Whereas a heart attack is caused by a halting of
blood flow to the cardiac muscle, cardiac arrest is an electrical event causing the heart to stop
beating. Listen more about the difference between a heart attack and cardiac arrest at
Healthology by clicking on the link: "What is a Heart Attack?" (O) Ventricular fibrillation, a
specific type of arrhythmia, can lead to cardiac arrest. The electrical problems experienced in
cardiac arrest are usually the result of some underlying cardiovascular disease. Travel to
Merck.com to read a description of ventricular fibrillation (R). The site also contains images of
electrocardiograms: one normal and the other showing ventricular fibrillation. To view an
animation of ventricular fibrillation, travel to the National Heart Lung and Blood Institute's
website, then scroll down the webpage to the last animation (O).

Although cardio-pulmonary resuscitation (CPR) is a valuable skill which may help in sustaining
life, many organizations recommend automated external defibrillators (AED) be installed in
public places in the event of cardiac arrest. Automated external defibrillators (AED's) are
portable devices used to defibrillate the heart during cardiac arrest. You can see how an AED
operates by traveling to Philips Medical Systems HeartStart FR2+ Demo links to view an AED
demonstration. For a cardiac arrest demo, travel to Physio-Control (O). For more information on
AED, read "What is an AED and how does it work," as well as "Effectiveness of AED" at the
Heart and Stroke Foundation of Canada. (R)

Thrombus

A thrombus is when a piece of tissue, a blood clot or other foreign body present in a blood vessel
prevents adequate blood delivery, which could lead to tissue damage or tissue death. In
cardiovascular disease, a thrombus is usually caused by a blood clot existing in a blood vessel.
These clots can form whenever the vessel is damaged. The damaged vessel will bleed, and the
bleeding will eventually stop through the normal clotting process. The clot can decrease blood
flow to tissue, or it can completely impede blood flow. The Stroke Center has an image of a
thrombus (O). For those interested in more information, Peter Libby, MD presents a detailed
audio Quicktime feature, "Multiple Mechanisms of Arterial Thrombosis" (O--QuickTime
software needed).

Embolus

An embolus is when a piece of tissue, a blood clot or other foreign body circulates in the blood
and becomes trapped in a blood vessel too small to let it pass. In cardiovascular disease, an
embolus may occur when a thrombus has detached, travels to another blood vessel and slows or
stops blood flow at the new site. Travel to HeartCenterOnline.com to view an image of an
embolus in a blood vessel (R).

Stroke

A stroke occurs when part of the brain dies because it does not receive the blood that it needs.
Marked by a sudden weakness, numbness or paralysis in certain parts of the body, sudden
speech, sight, walking or thinking changes, a stroke can occur as a result of a blockage (embolus,
thrombus), which is the most common reason, or through bleeding (an aneurysm or hemorrhage).
To see an animation related to stroke and its causes (embolus, thrombus, atherosclerosis), visit
the University of Maryland Medical Center (O). To read about symptoms of stroke, visit
Stanford Hospital (O).

The Centers for Disease Control and Prevention describe racial and ethnic disparities in stroke
(O).

In 2008, the Stroke Collaborative--a joint venture among the American Academy of Neurology,
the American College of Emergency Physicians, and the American Heart Association--is trying
to educate the general public on five stroke symptoms (O).

Congestive Heart Failure

A diseased heart is not able to pump blood effectively. As a result, the blood "backs up" in the
veins leading to the heart, which can lead to pulmonary (lung) congestion. Symptoms include
swelling in the legs, ankles, and an inability of the kidneys to excrete water and sodium
efficiently, making the swelling worse. Congestive heart failure is usually diagnosed through a
variety of exams: a blood test, a physical, medical history evaluation, catheterization, ECG,
echocardiogram, and chest x-ray are often used. You can see an x-ray of a normal heart and an
enlarged heart at the Franklin Institutel (O). The Health Library has an illustration comparing the
size of a normal heart to an enlarged heart (O). Myhealth.com provides an illustration showing
the difference between a normal-sized and enlarged heart (O). A sensitive photo via National
Geographic shows a medical worker holding up a normal-sized heart and an enlarged heart (O).

Rheumatic Heart Failure

This condition is the result of rheumatic heart fever, in which heart valve damage occurs after a
strep infection. This is one reason why physicians take strep throat so seriously in children. In
rheumatic fever, the inner lining of the heart is inflammed and the valves may scar, causing an
inability for them to open or close properly (heart murmur). This condition may eventually
require a valve replacement. To hear a heart murmur, visit the University of Michigan Health
System (O).

Last Revised: 10-3-08

 

								
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