Transcript Chapter 2 - Preventing Cardiovascular Disease

Chapter 2: Preventing Cardiovascular
Disease
 Cardiovascular disease is the leading cause
of death in the U.S.— 42% of all deaths
 Approximately 1.5 million heart attacks
occur each year—500,000 are fatal
 About 50% of people who
have heart attacks wait
2 hours before seeking
medical attention
Anatomy of the Heart
The heart:
 Consists of cardiac muscle
 Weighs 8 to 10 ounces
 Has two halves (pumps)
divided by the septum
 Halves are divided into upper chambers
(atria) and lower chambers (ventricles)
Circulation
 The left side of the heart
(systemic pump) receives
the oxygenated blood
from the lungs and
pumps it to all the tissues
in the body
 The right side of the
heart (pulmonary pump)
receives deoxygenated
blood from the body and
pumps it to the lungs
Circulation
 The primary function of
circulation is to provide a
constant supply of blood and
nutrients to cells while
removing their waste products
 The heart has its own
conduction system
 The beating rate and rhythm
are established by the sinoatrial
(SA) node (pacemaker)
Circulation
 The electrical contraction pauses at the
atrioventricular (AV) node, allowing the
ventricles to fill with blood
 The heart is supplied with blood from
coronary circulation after it has been ejected
from the heart
 Blood is so important to the heart that every
muscle fiber is supplied by at least one
capillary
Cardiovascular Disease (1)
 Coronary heart disease (coronary artery
disease; CAD) is diagnosed when any artery
is narrowed by 60% or more
 A myocardial infarction (heart attack; death
of the heart muscle) occurs when blood flow
to the heart muscle is disrupted
 Most heart attacks occur after age 65, but
the process begins as early as adolescence
Myocardial Infarction
 The medical term for heart attack is
myocardial infarction (MI)
 Up to one third of all heart attacks are
silent—without obvious signs or symptoms
 Silent ischemia, reduced blood flow, can
initiate heart attacks without warning
 Most heart attacks are obvious
Cardiovascular Disease (2)
 Heart disease is an acquired
disease that is preventable
 Americans as young as 18
have obstructions in their
coronary arteries caused by
atherosclerosis
 Atherosclerosis, characterized
by plaque beneath artery
linings, is responsible for 80%
of CAD deaths in the U.S.
Brain Attack (Stroke)
 Brain attacks are caused by a
thrombus or an embolus (70%
to 80%) or a cerebral
hemorrhage
 Brain cells die, causing loss of
function of some parts of the
body
 Brain attacks have the same risk
factors and prevention factors as
heart disease
Unchangeable Risk Factors for Heart
Disease (AHA)
 Age—80% of fatal heart attacks occur
after age 65
 Male gender—Heart disease is the leading
cause of death for both males and
females
» Females have a lower rate than males
» Rate is increasing among females, particularly
those who smoke and use oral contraceptives
 Heredity and Race—A tendency toward
heart disease appears to be hereditary
Changeable Risk Factors
Cholesterol (1)
 A certain amount of cholesterol
is necessary for good health
 The best way to lower serum
(blood) cholesterol is to reduce
intake of saturated fat
 Saturated fat increases the
liver’s production of cholesterol
Changeable Risk Factors
Cholesterol (2)
 Cholesterol is a steroid that does not dissolve
in blood, so it is transported to cells by
protein packages
 Low-density lipoproteins (LDL), the primary
transporters of cholesterol, are the most
capable of producing atherosclerosis
 People with low blood levels of LDL (less
than 100 mg/dl) rarely have heart attacks
Changeable Risk Factors
Blood Pressure (1)
 Blood pressure is the force exerted against
artery walls as blood travels through the
circulatory system
 High blood pressure (hypertension) has no
signs or symptoms
 An estimated 90% to 95% of hypertension is
essential (of unknown origin)
 High BP= 140/90 mmHg
Changeable Risk Factors
Blood Pressure (2)
 Long-term uncontrolled
hypertension increases the work
of the heart, causes it to
hypertrophy, and leads to
congestive heart failure
 Hypertension damages the
arteries, accelerates
atherosclerosis, and is the most
important risk factor for brain
attacks
Changeable Risk Factors
Tobacco
 Cigarette smoking may be the most harmful
of the preventable risk factors for chronic
illness and premature death
 These illnesses include chronic bronchitis,
emphysema, strokes, and 87% of all lung
cancers
 Passive smoking, inhaling the smoke of
others, causes the deaths of 38,000 to
43,000 nonsmokers annually
Changeable Risk Factors
Physical Inactivity
 Physical inactivity increases
the risk of coronary heart
disease by 1.5 to 2.4 times
 The greatest health benefits
are gained when people
expend 1500 to 2000 calories
(walk 15 to 20 miles) per
week
 Exercise for health does not
have to be as strenuous as
exercise for physical fitness
Changeable Risk Factors
Physical Inactivity
 Physical activity is any physical
movement that results in energy
expenditure—walking, mowing
the lawn, vacuuming
 “Every U.S. adult should
accumulate 30 minutes or more
of moderate intensity physical
activity on most, preferably all,
days of the week.” (ACSM/CDC
statement)
Changeable Risk Factors
Obesity
 Obesity contributes to about 300,000 deaths
per year
 Fat that accumulates in the upper half of the
body (central abdominal obesity) is
significantly more likely to contribute to
heart disease
 A 5% to 10% weight loss that is maintained
can significantly reduce the risk of heart
disease
Changeable Risk Factors
Diabetes Mellitus
 Diabetes is a metabolic disorder in which the
body cannot properly use sugar (glucose) as
fuel
 Type II (90% of all diabetes) occurs in older,
overweight, sedentary adults
 Diabetes increases the risk of coronary artery
disease 2 to 3 times in men and 3 to 7 times
in women
Changeable Risk Factors
Stress
 Stress elevates heart rate,
blood pressure, breathing
rate, and blood sugar
levels, activates the
immune response, and
causes other physiological
changes
 Chronic (long-term)
distress significantly
strains the body
Prevention of Heart Disease
Prevention includes:
 Regular exercise
 Optimal body weight
 Sound nutritional practices
 Nonuse of tobacco and other drugs
 Nonuse or moderate use of alcohol
 Dealing constructively with stress
 Periodic medical examinations
Diagnostic Techniques
 Medical examination and patient history
 Exercise stress tests
 Thallium treadmill test
 Echocardiography
 Cardiac catheterization
Medical Treatment
 Low-dose aspirin therapy
 Coronary artery bypass surgery
 Balloon angioplasty
 Coronary stent
 Artificial valves
 Left ventricular assist devices
 Heart transplants