Download Cardiovascular disease

Chapter 14
Cardiovascular
Diseases
Cardiovascular Diseases:
Understanding Risks and Measures of Prevention
Learning Objectives
1. Describe how the heart functions.
2. Define cardiovascular disease, infarction,
coronary heart disease, stroke, and heart
attack.
3. Explain the role atherosclerosis plays in heart
disease.
4. Identify and explain types of heart surgeries
used to repair blocked arteries.
Cardiovascular Diseases:
Understanding Risks and Measures of Prevention
• Learning Objectives (continued)
5. Identify the major risk factors of heart disease
that cannot be changed, major risk factors that
can be changed, and other contributing factors.
6. Explain the role of homocysteine in heart
disease.
7. Discuss various ways to reduce cholesterol
levels.
Cardiovascular Diseases:
Understanding Risks and Measures of Prevention
• Learning Objectives (continued)
8. Explain how stress contributes to
hypertension.
9. List dietary supplements and foods that help
maintain a healthy cardiovascular system.
Cardiovascular Diseases:
Understanding Risks and Measures of Prevention
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Understanding Cardiovascular Diseases
Atherosclerosis
Risk Factors for Cardiovascular Disease
Diet and Cardiovascular Disease
Preventing Cardiovascular Disease
Understanding
Cardiovascular Diseases
• Cardiovascular disease refers to a number of
conditions that damage the heart or arteries.
– Heart attack—if the coronary arteries (large blood
vessels that carry blood to and from the heart)
become diseased or blocked, a heart attack may
result.
– Infarction—if the heart does not receive a continual
supply of blood and oxygen, the heart cells die.
– Ischemia—this occurs when the blood supply to the
heart is only partially blocked.
Understanding
Cardiovascular Diseases
– Stroke occurs when there
is damage to the brain
from an insufficient
supply of blood to the
brain cells.
• Cardiovascular diseases
are preventable and
primarily are lifestyle
diseases.
Understanding
Cardiovascular Diseases
Understanding
Cardiovascular Diseases
• The Heart and Blood Vessels
– Arteries carry oxygenated blood from the heart
to all organs and tissues in the body.
– Veins return blood to the heart after oxygen and
nutrients have been exchanged for carbon
dioxide and waste products.
– Capillaries: tiny blood vessels that branch out
from arteries and veins and circulate blood to
all the cells in the body.
– Myocardium: muscular wall of the heart.
Understanding
Cardiovascular Diseases
Understanding
Cardiovascular Diseases
• The Heart and Blood Vessels (continued)
– Heart
• Upper two chambers are called the left atrium and
the right atrium.
• Lower two chambers are called the left ventricle and
the right ventricle.
Understanding
Cardiovascular Diseases
• The Heart and Blood Vessels (continued)
– Heart
• Blood that is depleted of oxygen returns to the heart
via the right atrium.
• Blood flows to the right ventricle and is pumped to
the lungs, where it is reoxygenated and returned to
the left atrium via the pulmonary vein.
• This fresh blood is pumped throughout the body’s
tissues from the left ventricle through the large
artery called the aorta.
Understanding
Cardiovascular Diseases
• The Heart and Blood Vessels (continued)
– Heart Rhythm
• Beats 60–100 times per minute.
• Controlled by the sinoatrial node in the right atrium.
– Sends an electrical signal across the surface of the heart;
this causes the fibers to contract.
• The brain can affect the heart rate as well.
Understanding
Cardiovascular Diseases
• The Heart and Blood Vessels (continued)
– Heart Rhythm
• Arrhythmia: irregular heartbeat.
• Atrial fibrillation: when signals other than those
coming from the sinoatrial node interfere with the
heartbeat and cause different areas of the heart to
beat independently of one another.
Understanding
Cardiovascular Diseases
• The Heart and Blood Vessels (continued)
– Heart Rhythm
• Can be managed with drugs or pacemaker.
• Pacemaker: small electrical device implanted in a
person’s chest that supplies a steadying electrical
signal to the heart.
Understanding
Cardiovascular Diseases
• Defibrillators: External and Implanted
– When sudden cardiac arrest is caused by atrial
fibrillation, heartbeat is erratic and death ensues
unless a regular heartbeat can be restored quickly.
– Defibrillator: an electrical device that can restore
normal heart rhythm by delivering electrical shocks
through the chest to the heart.
– Defibrillation should be initiated within a few
minutes after the beginning of a heart attack in
order to enhance survival.
Understanding
Cardiovascular Diseases
• Defibrillators (continued)
– AED: automated external defibrillator.
• Kept in public places for individuals to use on
someone whose heart is in defibrillation.
– ICD: implantable cardioverter defibrillator.
• A small unit, implanted in the chest with wires
attached to the heart, that delivers an electrical
shock if necessary to restart the heart.
• Most people who have these do not ever need
an electrical shock.
Understanding
Cardiovascular Diseases
• Defibrillators (continued)
– Heart transplant is a last resort for a failing heart;
40% of new hearts are rejected after the
transplant.
Understanding
Cardiovascular Diseases
• Regulating Blood Flow
– The cardiovascular system is equipped with
one-way valves in the chambers of the heart
and blood vessels.
– With every heartbeat, the valves open and close
to allow blood to flow in one direction.
– Defective valves can be replaced or repaired to
allow normal function.
– Valves can be damaged by childhood throat
infections such as “strep throat.”
Understanding
Cardiovascular Diseases
• Heart Valves
Atherosclerosis
• Arteriosclerosis: hardening of the arteries .
• Atherosclerosis: the formation of plaque.
• If coronary arteries become partially blocked
and the heart does not receive enough oxygen,
chest pain (called angina pectoris) occurs.
• Angina pectoris: chest pain that occurs when
coronary arteries become partially blocked
and the heart cells do not get enough oxygen.
• If the coronary artery is blocked completely, a
heart attack occurs.
Atherosclerosis
Atherosclerosis
• Diagnosis of a Heart Attack
– More than a million people are admitted to
hospitals annually with possible heart attacks.
– Diagnosing a heart attack is time-consuming and
costly.
– Blood levels of the following proteins change
during a heart attack:
•
•
•
•
Creatine kinase
Troponin
Myoglobin
Myosin
Atherosclerosis
• Cardiopulmonary Resuscitation (CPR)
– An emergency procedure administered to a
person who has stopped breathing; this
involves:
• Mouth-to-mouth breathing
• Repeated compression of the chest
– The rules are now the same for adults and
children:
• 30 compressions / 2 breaths
Atherosclerosis
• Cardiopulmonary Resuscitation (continued)
– Four steps for CPR:
• Place the person carefully on his or her back. Tilt the
head back and lift the chin until the teeth almost
touch. Look for signs of breathing.
• If the person is not breathing, pinch the nose and
give the person two full breaths about two seconds
long to produce a visible chest rise.
Atherosclerosis
• Cardiopulmonary Resuscitation (continued)
– Four steps for CPR
• Place your hands in the center of the person’s chest
between the nipples. Place one hand on top of the
other, and with the elbows locked, press the heel of
your hand into the chest.
• Give 30 rapid compressions for every 2 full breaths;
repeat until medical help arrives or until the person
starts breathing.
– Make sure you are properly trained!
Atherosclerosis
• Repairing Blocked Arteries
– Cardiac catheterization: when a thin tube is
threaded from an artery in a leg or arm up to the
coronary arteries to view the blood flow.
– Coronary artery bypass surgery: the diseased
segment of an artery is cut out and replaced
with a grafted piece of good artery to restore
normal flow of blood to the heart.
Atherosclerosis
• Repairing Blocked Arteries (continued)
– Open-heart surgery: the heart is exposed while
being repaired, and blood is diverted through a
heart–lung machine.
Atherosclerosis
• Repairing Blocked Arteries (continued)
– An alternative surgical procedure is
percutaneous transluminal coronary
angioplasty (PTCA), in which a balloon is
inserted into the artery and inflated so it pushes
the plaque against the wall of the artery,
opening the artery.
• Costs less than bypass surgery, but often the
blockage recurs.
Atherosclerosis
• Repairing Blocked Arteries (continued)
– Alternative to bypass surgery is “stenting,”
which involves inserting a catheter into an
artery in the arm or leg, threading it to the
blockage point, and inserting “stents” to prop
the artery open.
• Simpler, cheaper, and safer than bypass surgery.
Atherosclerosis
• Repairing Blocked Arteries (continued)
– Studies have shown that blockages can be
improved through lifestyle changes.
– These costly procedures may not be necessary
100% of the time.
– Most patients look for the quick fix and want
surgical intervention.
Atherosclerosis
• Stroke
– Third leading cause of death in the United
States, after coronary heart disease and cancer.
– High blood pressure is related to at least 70% of
all strokes.
– It is a form of cardiovascular disease that
affects arteries supplying blood to the brain.
– Brain cells die within minutes without oxygen.
Atherosclerosis
• Stroke (continued)
– A person who has had a stroke can lose the
ability to speak, have one arm or leg become
paralyzed, become paralyzed on one side of the
body, or die.
– Can occur from injuries to the head or from
weak spots in the arteries, called aneurysms,
that balloon and rupture.
– Can occur when a weak heart cannot pump
enough blood to the brain.
Atherosclerosis
• Stroke (continued)
– Two kinds of stroke
• Ischemic stroke occurs when one or more blood
vessels in the brain become blocked due to a clot in
an artery in the brain or in one leading to the brain.
• Hemorrhagic stroke results when a blood vessel in
the brain ruptures.
Atherosclerosis
• Stroke (continued)
– Signs of a stroke include:
• Sudden weakness or numbness of the face, arm, or
leg on one side of the body.
• Sudden dimness or loss of vision, especially in
one eye.
• Loss of speech, difficulty understanding speech, or
trouble talking.
• Sudden, severe headaches with no known cause
• Unexplained unsteadiness, dizziness, or fall.
Atherosclerosis
• Stroke (continued)
– Best way to prevent a stroke is to reduce the
risk factors that are controllable largely by
changes in lifestyle:
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High blood pressure
Heart disease
Cigarette smoking
Transient ischemic attacks
High red blood cell count
Risk Factors for
Cardiovascular Disease
• Research seems to indicate that plaque
begins to build up in the arteries at an early
age; this is why positive lifestyle behaviors
are important at all ages.
• Risk Factors
– Smoking
– Overweight and diabetes mellitus
– Hypertension
– Hypercholesterolemia
Risk Factors for
Cardiovascular Disease
Risk Factors for
Cardiovascular Disease
• Cholesterol
– Cholesterol—two major kinds are HDL
(“good” cholesterol) and LDL (“bad”
cholesterol).
– Familial hyperlipidemia: a rare inherited
disease that results in high levels of cholesterol
in the blood.
Risk Factors for
Cardiovascular Disease
• Cholesterol (continued)
– LDL Cholesterol
• Is deposited in plaques and blocks the arteries;
comes mainly from LDL cholesterol.
• As LDL circulates in the blood, cholesterol is used
by tissues to build new cells.
• If too much LDL is in the blood, the liver might not
be able to process it all; if not, the liver sends it back
out into the blood stream where it is deposited in the
walls of the arteries.
Risk Factors for
Cardiovascular Disease
• Cholesterol (continued)
– HDL Cholesterol
• Particles are produced in the liver and intestines and
released into the blood stream.
• As the particles circulate, they pick up cholesterol
and return it to the liver for removal.
Risk Factors for
Cardiovascular Disease
• Cholesterol (continued)
– Total cholesterol levels are measured in
milligrams per deciliter (mg/dl) of blood.
– A cholesterol level below 200 mg/dl indicates a
relatively low risk of coronary heart disease.
– A level of 240 mg/dl or higher doubles the risk
of coronary heart disease (CHD).
– Total cholesterol may not be a reliable indicator
because high levels of HDL may counteract the
bad effects of a high LDL count.
Risk Factors for
Cardiovascular Disease
Risk Factors for
Cardiovascular Disease
• Cholesterol (continued)
– Cholesterol, Statins, and Inflammation
• Statins are a class of drugs that reduce the level of
blood cholesterol.
• Statins also reduce the level of reactive protein in
the blood.
• Statins also reduce inflammation in arteries.
Risk Factors for
Cardiovascular Disease
• Cholesterol (continued)
– High Blood Pressure
• Approximately 30% of Americans 18 years old and
older have high blood pressure.
• If the cause of high blood pressure (HBP)
is unknown, it is referred to as essential
hypertension.
• This includes 90% to 95% of cases of HBP.
• The remaining HBP cases are symptoms of
recognizable diseases, such as kidney abnormality,
congenital defect of the aorta, or adrenal gland
tumor (secondary hypertension).
Risk Factors for
Cardiovascular Disease
• Cholesterol (continued)
– Measuring Blood Pressure
• The systolic pressure is the maximum pressure in the
arteries that occurs when the heart contracts.
• The diastolic pressure is the pressure between
contractions, when the pressure falls as blood flows
from one chamber to another.
• Normal blood pressure is defined as less than 140/90
(systolic/diastolic).
Risk Factors for
Cardiovascular Disease
• Cholesterol (continued)
– Lowering Blood Pressure
• Can be lowered by making the following lifestyle
changes:
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Lowering excessive caloric intake
Increasing physical activity
Decreasing salt and alcohol consumption
Consuming adequate amounts of potassium
Risk Factors for
Cardiovascular Disease
Risk Factors for
Cardiovascular Disease
• Cigarettes and Cardiovascular Disease
– Smokers have 2–4 times greater risk of dying
from a heart attack than nonsmokers.
– Secondhand smoke also increases risk.
– Stopping smoking at any time reduces these
risks.
Risk Factors for
Cardiovascular Disease
• The Metabolic Syndrome
– Factors that are shared by people at risk for
diabetes, CVD, and heart attack:
• Waist circumference larger than 40 inches in men
and 35 inches in women.
• Serum triglyceride level of 150 mg/dl or greater
• Blood pressure 135/85 or higher.
Risk Factors for
Cardiovascular Disease
• Stress
– Main risk factor for heart disease is stress.
– Type A behavior includes:
• Time urgency, impatience
• Hostility
• Achievement striving
• Salt
– There is no scientific evidence that reducing
salt intake reduces blood pressure.
Diet and Cardiovascular Disease
• A deficiency of only one nutrient can impair
the body’s ability to use all others, even if
the others are present in sufficient amounts.
• B vitamins—B6, B12, and folic acid lower
the levels of homocysteine in the blood.
• Calcium deficiency is a risk factor for
hypertension in persons of all ages.
Diet and Cardiovascular Disease
• Soy products help remove cholesterol from
the blood and block oxidation of LDL,
which prevents LDL particles from sticking
to the walls of arteries.
• Fish oils—populations that consume large
amounts of fish show lower rates of CHD
than populations that do not.
Diet and Cardiovascular Disease
• Trans fats—high levels are found in
margarine and many fast foods. This fat acts
the same as a saturated fat.
• Tea—green and black teas contain
antioxidant chemicals that help block
oxidation of LDL in the blood.
Diet and Cardiovascular Disease
• Aspirin
– Significantly reduces the risk of CHD and heart
attacks.
– Helps “thin” blood and combats inflammation.
– If you might be having a heart attack, call 911,
then take a couple aspirin to help prevent clotting.
• Alcohol
– In one study, men who had one or two drinks per
day over 12 years reduced their risk of dying from
heart attacks by about 20% compared with men
who did not drink alcohol.
Diet and Cardiovascular Disease
• Coffee, Tea, and Cocoa
– Moderate coffee does not seem to raise CVD risk.
– Polyphenols in tea seem to provide cardiovascular
protective effects.
– Flavonoids in unprocessed cocoa seem to increase
blood flow and reduce high blood pressure
development.
Preventing Cardiovascular Disease
• Now that you are armed with knowledge
about reducing the chances of heart attacks
and stroke, what needs to be done?
– Reduce weight.
– Reduce consumption of foods with saturated fats.
– Eat a lot of fruits and vegetables.
– Take supplements.
– Don’t smoke.
– Be active.
Cardiovascular Diseases:
Understanding Risks and Measures of
Prevention
• Is CVD something that runs in your family?
• What things does your family do that may
further that risk?
• What things does your family do that may
decrease that risk?
• How will you protect yourself, whether or
not your family is at risk for CVD?