Do you think medical researchers are able to assess accurately the factors that are detrimental or helpful to cardiovascular health? Why do you feel this way? How do you think your attitudes concerning medical research affect your behavior? Have your attitudes about medical research and cardiovascular health changed since reading this chapter? Why or why not?
Chapter 12
Cardiovascular
Health
Cardiovascular System and How it
Works: Blood
• Red blood cells (carry oxygen)
– Plasma (transports gases)
– Platelets (clotting factor)
– White blood cells (protect body from infection)
Cardiovascular System and How it
Works: Heart
• Four chambers
– Two atria
– Two ventricles
• Coronary arteries supply heart with blood
Cardiovascular System and How it
Works: Blood Vessels
• Arteries
– Carry blood away from the heart
– Branch into smaller blood vessels called
arterioles, which branch into smaller vessels
called capillaries
Cardiovascular System and How it
Works: Blood Vessels
• Capillaries
– Permeate tissues
– Allow substances such as nutrients and oxygen
to move out of blood and waste products and
carbon dioxide to move into blood
Cardiovascular System and How it
Works: Blood Vessels
• Veins
– Return blood to the heart
– Have thinner walls than arteries
– Have one-way valves which help prevent the
back-flow of blood
Cardiovascular System and How it
Works: Blood Vessels
• Varicose veins
– Distended or stretched veins found most
frequently in the legs or trunk
– Increases with age
– Men more likely to have severe venous disease
– Risk factors include family history, high blood
pressure, standing for prolonged periods.
Cardiovascular System and How it
Works: Blood Vessels
• Coronary arteries
– Arise from the base of the aorta
– Bring freshly oxygenated blood to heart muscle
– The left and right coronary arteries are the two
main coronary arteries.
• Branch into multiple arteries that supply the
entire heart with blood
Cardiovascular Diseases
• Hypertension (chronic high blood pressure)
• Stroke (blood vessel disease of the brain)
• Rheumatic heart disease
• Atherosclerosis (blood vessel disease)
– Coronary artery disease and stroke result from
atherosclerosis
Cardiovascular Disease:
Atherosclerosis
• Plaques (fatty deposits) develop inside arteries.
• May begin with an injury to the artery lining
• Lipids, especially cholesterol, accumulate at injury
sites and cling to the interior of the blood vessel walls.
• Scar tissue forms and calcium is deposited, hardening
the artery.
Cardiovascular Disease:
Atherosclerosis
Cardiovascular Disease:
Atherosclerosis
• Blood clots sometimes develop at this site.
– Blood clots are often the cause of heart attack or
stroke.
• Incidence increases with age.
– Not all elderly have extensive plaques and some
young people do.
Cardiovascular Disease: Coronary
Artery Disease (CAD)
• Blocked coronary arteries
– Result in heart attack
– Angina pectoris (chest pain)
• One out of every three Americans has one or more
forms of CVD.
Cardiovascular Disease: Coronary
Artery Disease (CAD)
• In CAD, coronary vessels become partly or
completely blocked by plaque and/or blood clots.
• Peripheral blood vessel disease—blockages
occurring in organs and tissues other than the heart
Cardiovascular Disease: Coronary
Artery Disease (CAD)
• Thrombus—stationary blood clot; can block blood
vessel where it forms.
• Coronary thrombosis—the development of a thrombus
that blocks a coronary artery
• Embolus—floating blood clot; forms and floats until it
blocks a blood vessel downstream
• Coronary embolism—produced when an embolus
blocks a coronary artery downstream from where it
was formed
Cardiovascular Disease: Coronary
Artery Disease (CAD)
• Blockage or spasm reduces blood flow to heart muscle
and results in angina pectoris.
– Angina is felt beneath the breastbone and extends
into left shoulder and down left arm.
– May also be felt in jaw, neck, or back
– Angina pain is described as aching, squeezing,
burning, heaviness, or pressure.
Cardiovascular Disease: Coronary
Artery Disease (CAD)
• Angina attacks can be brought on by:
– Physical exertion
– Mental or emotional stress
• Angina should not be ignored.
– Sign of serious CAD
• An echocardiogram, angiogram, or MRI will detect
blockages.
Cardiovascular Disease: Unclogging
Arteries
• Angioplasty
– Method of reconstructing damaged arteries to
improve blood flow
– Balloon angioplasty—balloon is inserted and
inflated, breaking up the plaque while compressing
it against the arterial wall
• Atherectomy
– Use of a cutting-tipped catheter to remove plaque
Cardiovascular Disease: Unclogging
Arteries
• Stenting
– Implantation of a mesh device within artery to keep
it open
– Some designed to inhibit clog recurrence
• Coronary artery bypass graft surgery
– Blood vessel taken from another part of the body
grafted to the aorta and to new blood vessel,
bypassing the blocked portion of diseased vessels
Cardiovascular Disease: Heart Attack
• One-third to one-half of people with CAD are
stricken suddenly and unexpectedly with a heart
attack (myocardial infarction).
• An infarction is an area of tissue that dies due to
insufficient blood flow and lack of oxygen.
−Arrhythmias
−Heart failure
−Cardiac arrest
−Death
Cardiovascular Disease: Heart Attack
• Congestive heart failure
– Heart cannot pump effectively and veins bringing
blood to the heart become overfilled with blood.
– Causes include CAD, heart defects, and rheumatic
heart disease.
– Primary signs and symptoms are shortness of breath,
retention of fluid, congestion of lungs, and fatigue.
Cardiovascular Disease: Heart Attack
• Cardiac arrest
– May occur as a result of heart attack
– Heart suddenly stops beating
– Immediate defibrillation is needed to avoid death.
– About 380,000 persons in the United States
experience sudden cardiac death each year.
Cardiovascular Disease:
Heart Attack
• Automated external defibrillators (AEDs) can be
used to shock a heart back into rhythm.
• AEDs are available in many public locations.
• The American Heart Association recommends
being trained to use an AED.
Cardiovascular Disease:
Heart Attack
• Applying cardiopulmonary resuscitation (CPR)
doubles or triples victim’s chance of survival.
• The American Heart Association 2-step method
1. Call 9-1-1 and provide your specific location.
2. Push hard and fast in the center of the chest to
the beat of Stayin’ Alive.
Cardiovascular Disease: Heart Attack
Signs and Symptoms
•
•
•
•
•
•
Pressure or heaviness in the chest
Shortness of breath
Profuse sweating
Weakness
Anxiety
Nausea
Cardiovascular Disease: Stroke
• A stroke occurs when arteries that supply brain become
blocked, preventing blood flow.
• May also occur if a blood vessel in the brain bursts
(cerebral hemorrhage)
• Aneurysm—swollen, weakened blood vessel; may
rupture
Cardiovascular Disease: Stroke Signs
and Symptoms
• Weakness, numbness, or paralysis on one side of the
body
• Loss or dimming of vision
• Loss of speech or difficulty speaking or understanding
speech
• Sudden severe headache
• Sudden dizziness, unsteadiness, or episodes of falling
Cardiovascular Disease: Stroke
Prevention
• Carotid endarterectomy—removal of the inner lining
of a partially blocked carotid artery
• Transient ischemic attacks (TIAs) are small strokes that
usually cause no permanent damage but warn of bigger
stroke.
• Blood-thinning drugs may be prescribed.
Risk Factors for Cardiovascular Disease
Modifiable
• Cigarette smoking
• Obesity
• Chronic high blood
pressure
• Sedentary lifestyle
• Diabetes mellitus
• Anxiety and stress
• Abnormal blood lipids
Unmodifiable
• Male gender
• Increasing age
• Family history of
cardiovascular disease
Risk Factors for Cardiovascular Disease:
Blood Lipids
• HDL or “good” cholesterol
• Helps remove cholesterol from the body
• High levels of HDL lower risk of CAD
• LDL or “bad” cholesterol
• Carries cholesterol to the cells, including those
that line arteries
• High levels of LDL raise risk of CAD
Risk Factors for Cardiovascular
Disease: Blood Lipids
• Desirable HDL ≤ 40 mg/dl (50 for women)
• Desirable LDL < 100 mg/dl
• Excess triglycerides in the plasma are linked to CAD
and stroke in some people.
• Normal fasting triglyceride = less than
150 mg/dl
Risk Factors for Cardiovascular
Disease: Cigarette Smoking
• Significantly increases the risk of heart attack and
stroke (2 to 4 times)
• Tend to have reduced HDL levels and increased LDL
• Tend to have increased levels of clotting factors
• Compounds in cigarette smoke damage blood vessels,
leading to atherosclerosis.
Risk Factors for Cardiovascular
Disease: High Blood Pressure
• Normal pressure is less than 120/80 mm Hg.
• Systolic BP—pressure exerted on artery walls when the
heart’s left ventricle contracts
• Diastolic BP—pressure exerted on artery walls when
left ventricle relaxes
• Prehypertension—systolic pressure reading between
120 and 139 or diastolic pressure is between 80 and 89
Risk Factors for Cardiovascular
Disease: High Blood Pressure
– Stage 1 hypertension—systolic reading between 140
and 159 or a diastolic reading of 90 to 99
– Stage 2 hypertension—systolic reading of 160 or
more or a diastolic reading of 100 or more
– Persistently high arterial blood pressure contributes to
the development of atherosclerosis.
Risk Factors for Cardiovascular
Disease: Physical Inactivity
• Sedentary people are twice as likely to develop CAD as
active people.
• 150 minutes/week of physical activity lowers the risk
of heart disease and stroke.
• More than 50% of American adults do not get enough
physical activity; 25% are not active at all during
leisure time.
Risk Factors for Cardiovascular
Disease
• Obesity
– Obesity doubles the risk of CAD; even being mildly
overweight increases this risk.
• Diabetes mellitus
– Elevated blood glucose levels damage heart muscle,
small coronary arteries, and major arteries.
– Atherosclerosis occurs more frequently and at an
earlier age in diabetics, especially women.
Risk Factors for Cardiovascular
Disease
• Anxiety and stress
– Stress can result in spasms of the coronary arteries,
which can contribute to angina attacks.
– People with anxiety disorders are 2–6 times as likely
to die from a heart attack as people without.
• Elevated C-reactive protein
– An elevated blood level C-reactive protein can be a
positive risk factor for CVD.
Maintaining Cardiovascular Health
•
•
•
•
•
•
Refrain from smoking.
Maintain a healthy weight.
Exercise regularly.
Maintain healthy blood pressure levels.
Maintain healthy blood cholesterol levels.
Eat less fat and more fiber, practice relaxation, and
reduce sodium intake as necessary.
Across the Life Span
• Approximately 1% babies are born each year with a
variety of heart and blood vessel abnormalities.
• Congenital heart defects can be diagnosed before
birth with ultrasound of the heart (echocardiogram).
• CVD due to atherosclerosis has been shown to begin
in childhood.
• The elderly should be treated with lipid-lowering
therapy when needed, to help prevent the progression
of CVD and other diseases.
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