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Cardiovascular Diseases

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Title: Cardiovascular Diseases


1
Cardiovascular Diseases
  • By
  • Prof. Fathi El-Gamal
  • MB Ch B, M Sc, PhD (England)

2
Introduction
  • Cardiovascular disease (CVD) or diseases of the
    circulatory system can be described as
  • All diseases relating to the heart and blood
    vessels .

3
The main conditions include
  • Coronary heart disease,
  • Cerebro-vascular disease,
  • Hypertension
  • diseases of the pulmonary circulation,
  • peripheral vascular disease,
  • diseases of the arteries, veins, lymphatics,
  • rheumatic disease
  • and other circulatory conditions.

4
Introduction
  • Cardiovascular disease is a high priority health
    issue in the community. Why?
  • A large proportion of those
  • dying or
  • utilizing both acute and other health care
    support and services
  • are in fact suffering from
  • - various cardiovascular diseases
    or
  • - co-morbidities associated with
  • cardiovascular diseases

5
Introduction
  • Lifestyles are often affected by it, resulting in
    disability and/or deterioration in quality of
    life.
  • Cardiovascular disease accounted for 40 per cent
    of all deaths in develped countries, and 22 per
    cent of years of potential life lost.

6
(No Transcript)
7
Heart diseases are leading cause of death in
developed countries
8
Social and financial cost
  • Major issues related to cardiovascular disease
    include the considerable social and financial
    costs associated with it.
  • This implies that, if cardiovascular disease
    could be eliminated
  • huge amounts of current disability would also be
    eliminated
  • and people could enjoy healthy lives to a greater
    extent.

9
CARDIOVASCULAR DISEASE
  • At any given time, the distribution of blood in a
    person's body will be approximately
  • 64 veins,
  • 13 arteries,
  • 9 pulmonary vessels,
  • 7 heart and
  • 7 arterioles capillaries.

10
  • Although the heart weighs less than 1 of the
    total body weight, it relentlessly receives
    nearly 5 of the total blood flow
  • (which may explain why the arteries of the
    heart can so easily develop problems).

11
Common conditions associated with CVD
  • Congenital defects and infectious disease can
    strike any-where,
  • but by far the most common disease occurs in the
    arteries
  • atherosclerosis.

12
  • Blockages
  • can occur in veins as well as in arteries, but
    these tend to be caused by blood clots (thrombi)
    rather than by atherosclerosis.
  • Thrombophlebitis
  • (often simply called phlebitis) most commonly
    involves clotting of blood and inflammation of a
    vein in the leg.
  • This can be serious if a portion of the clot
    becomes detached, travels through the heart, and
    gets pumped to the lung where it blocks a
    pulmonary artery as a pulmonary embolism.
  • About 10 of people with pulmonary embolism die
    within an hour.

13
  • Clotting of blood in the veins can occur when
    blood flow is slow or stagnant.
  • This can occur during long periods of
    immobilization such as
  • when confined to a hospital bed,
  • cramped in a crowded airplane on a long flight
  • or driving for an extended period.

14
ATHEROSCLEROSIS
  • Arteriosclerosis (hardening of the arteries)
  • occurs "naturally" with aging as a result of
    cross-linking of macromolecules like proteins and
    polysaccharides.
  • Atherosclerosis
  • refers to the formation and hardening of fatty
    plaques (atheromas) on the inner surface of the
    arteries.
  • In atherosclerosis, the arteries not only harden,
    they narrow, sometimes narrowing so much that
    hardly any blood can get through.
  • Such narrowed vessels are easily blocked by
  • constriction or
  • objects in the bloodstream

15
  • The internal surface of an artery is covered with
    a single layer of endothelial cells that are
    pressed against each other like flagstones on a
    terrace.
  • Atherosclerosis begins with injury to
    endothelial cells, exposing portions of the
    artery surface below the endothelium.

16
  • Injury to the endothelium
  • Free radicals,
  • chemicals in cigarette smoke
  • or other irritants could be responsible for the
    injury,
  • as could turbulence and mechanical force due to
    high blood pressure.
  • Platelets clump around the injured endothelial
    cells and release prostaglandins, which cause the
    endothelial cells to proliferate like cancer.
  • LDL-cholesterol particles release their fat into
    the areas made porous by prostaglandins.

17
  • Macrophages (scavenger white blood cells) engorge
    themselves on oxidized LDL-cholesterol until they
    become unrecognizable "foam cells" that invade
    atheromas.
  • Then the atheromas are hardened by fibrin (which
    forms scar tissue) and finally by calcium
    patches.
  • A vicious circle often arises with scar tissue
    attracting more platelets and LDL-engorged
    macrophages.

18
ATHEROSCLEROTIC CARDIOVASCULAR DISEASE
  • Atherosclerosis can occur in any artery.
  • Most commonly it occurs in the aorta, the artery
    that receives blood directly from the heart.
  • Since the aorta is the largest artery in the
    body, it is rarely critically narrowed by
    atheromas.
  • Nonetheless, atherosclerosis can contribute to
    aneurysms (responsible for only one-fortieth the
    mortality rate of heart attack)

19
  • The most frequent life-threatening problems,
    however, are caused by the arteries supplying
  • the heart,
  • the brain
  • and the kidneys, in that order.
  • An estimated 70 of North Americans have coronary
    atherosclerosis (narrowing of the arteries of the
    heart), although the overt symptoms may not be
    evident until the arteries are three-quarters
    occluded.

20
  • Coronary artery atherosclerosis leads to
  • angina pectoris,
  • heart attack
  • and cardiac arrest.
  • Brain artery atherosclerosis leads to
  • transient ischemic attack (TIA)
  • and stroke.

21
Angina pectoris (Latin "strangling in the
chest")
  • The coronary vessels narrow temporarily causing
    the heart muscle to suffer ischemia (lack of
    oxygen).
  • This is often accompanied by symptoms of
  • crushing,
  • diffuse pain in the chest (directly over the
    heart),
  • a shortness of breath (air hunger) that leads to
    gasping,
  • weakness,
  • anxiety,
  • light-headedness (faintness ,dizziness )
  • nausea
  • and sweating..

22
Myocardial infarction (Heart attack)
  • The exact same set of symptoms occur in which a
    narrowed coronary artery becomes completely
    blocked, usually by a blood clot.
  • Heart muscle which formerly received blood from
    the blocked artery dies if deprived of oxygen for
    over 40-60 minutes.
  • (An area of dead tissue resulting from a blocked
    artery is called an infarct).

23
  • If enough heart tissue dies, the heart may stop
    altogether (cardiac arrest, also known as sudden
    cardiac death).
  • Although atherosclerosis is by far the most
    common cause of heart attack cardiac arrest,
    other causes include
  • coronary artery spasm,
  • electrical irregularities
  • and congenital defects.

24
  • Everything else being equal, the risk of heart
    attack is
  • doubled for a diabetic man
  • and increased 5 times for a diabetic woman.
  • Diabetes also doubles the risk of stroke
    independently from effects of heart disease and
    high blood pressure.
  • (although good control of blood glucose can
    reduce the risk. )

25
  • Risk factors for cardiovascular diseases

26
I. CIGARETTE SMOKING
  • Heart attacks are 3 to 4 times more likely to
    occur in a cigarette smoker than in a nonsmoker
  • and the smoker's heart attack is more likely to
    be fatal.
  • The risk of cardiac arrest is
  • 10 times greater for male smokers
  • and 5 times greater for female smokers
  • as it is for nonsmokers.

27
Passive smoking
  • Nonsmoking spouse of smokers have
  • twice the incidence of heart disease and
  • 2.5 times the incidence of lung cancer
  • as nonsmoking spouses of nonsmokers

28
  • In the Framingham study
  • male smokers were 40 more likely to suffer
    stroke than male nonsmokers
  • and female smokers were 60 more likely to
    experience stroke than female nonsmokers.
  • The lifespan of a smoker tends to be years less
    than that of a nonsmoker.

29
  • Tobacco smoke contains
  • tar, nicotine,
  • carbon monoxide, benzene,
  • nitrogen dioxide, formaldehyde,
  • hydrogen cyanide, nitrosamines and
  • polycyclic aromatic hydrocarbons
  • which are all known to be harmful

30
  • Many of these substances are capable of injuring
    the arterial endothelial cells to begin the
    atherosclerotic process.
  • Nicotine causes
  • adrenaline and nor-adrenaline release,
  • which elevates heart rate and blood pressure.

31
  • Carbon monoxide binds to hemoglobin 200 times
    more strongly than oxygen thereby
  • reducing the oxygen-carrying capacity of the
    blood
  • and thickening the bloodstream through
    compensatory red blood cell proliferation.
  • Smoking
  • lowers the level of beneficial HDL-cholesterol
  • and increases fibrinogen (promoting clotting).
  • Even without coronary atherosclerosis, smoking
    can lead to cardiac arrest by
  • causing the coronary arteries to go into spasm
  • or by promoting irregularities of heartbeat.

32
  • Within one year of quitting smoking, the risk of
    heart attack falls 50.
  • Within ten years, ex-smokers who smoked one pack
    per day or less have the same heart attack risk
    as those who have never smoked.
  • And the extra risk of stoke is eliminated within
    5 years of kicking the cigarette habit.

33
  • Groups led by professional counselors have a 35
    greater success rate in a period of a year than
    smokers who try to quit by themselves.
  • Groups that use nicotine chewing gum have an 80
    success rate.
  • Most ex-smokers succeed only after several
    attempts to quit.
  • A positive attitude to take after a failed
    attempt is to regard the failure as a learning
    experience -- and to incorporate what was learned
    by the failure in planning the next attempt.
  • Only one-third of ex-smokers gain weight, and
    most of those don't keep the extra weight.

34
II. HIGH BLOOD PRESSURE (HYPERTENSION)
  • Blood pressure is regulated by the sympathetic
    and parasympathetic branches of the autonomic
    nervous system.
  • In the sympathetic branch, pressure receptors in
    the aortic arch and the carotid arteries send
    signals to the vasomotor center of the brain
    stem.
  • When blood pressure drops, sympathetic nerves to
    the heart release norepinephrine, which promotes
    calcium uptake by heart muscle and acts on beta
    receptors of the heart to increase the strength
    and rate of heartbeat.
  • Sympathetic nerves also release norepinephrine to
    the alpha receptors of the arterioles, causing
    them to contract. All of these effects increase
    blood pressure.
  • The parasympathetic branch sends the vagus nerve
    to the heart, where it releases acetylcholine,
    causing the heart to beat more slowly, and with
    less force.

35
  • The kidneys can influence blood pressure by
  • (1) excreting more sodium and water (lowering
    blood
  • volume, and hence, lowering blood
    pressure) and
  • (2) secreting the enzyme renin which produces
  • angiotension I in the bloodstream.
  • When angiotension I reaches the lungs,
    Angiotension Converting Enzyme (ACE) converts
    angiotensin I to angiotension II, which rapidly
    and powerfully constricts the arterioles, raising
    blood pressure.

36
  • Blood pressure is measured by two values
  • the highest pressure, when the heart is pumping
    or Squeezing (Systolic),
  • and the lowest pressure, when the heart is
    relaxing or Dilating (Diastolic).
  • A pressure of 140 mmHg is the amount of force
    necessary to raise a column of Mercury (Hg) 140
    millimetres.
  • In North America, Systolic/Diastolic pressure of
    120/80 is considered "normal", although natives
    of New Guinea typically have a diastolic blood
    pressure of 60 mmHg -- and an extremely low
    incidence of stroke.

37
The following table indicates the hazards of high
blood pressure
  • __________________________________________
  • YEARS OF LIFE LOST DUE TO HIGH BLOOD PRESSURE
  • __________________________________________
  • Sys/Dia MEN (age) WOMEN
    (age)
  • 35 55
    35 55
  • __________________________________________
  • 130/90 4 years 1 year 2 years
    1 year
  • 140/95 9 years 4 years 5 years
    3 years
  • 150/100 17 years 6 year 9 years
    4 years
  • __________________________________________

38
  • People with hypertension are 2-3 times more
    likely to have a heart attack than those with
    normal blood pressure.
  • 45 of people with high blood pressure are
    unaware that they have it. Of those who are
    aware, fewer than half are being treated.
  • People with uncontrolled high blood pressure are
    7 times more likely to have a stroke than people
    with controlled high blood pressure.
  • Hypertension is the major risk factor for stroke.
  • 25 of people currently undergoing kidney
    dialysis can blame high blood pressure for their
    kidney damage.
  • High blood pressure also damages many other
    organs.

39
III. Obesity
  • 75 of overweight (over fat) people with
    hypertension who lost 20 pounds or more achieved
    normal blood pressure -- besides reducing their
    blood LDL and elevating their blood
    HDL-cholesterol.
  • Will-power to resist the temptations of hunger is
    at least as important in losing weight as the
    will-power to exercise.
  • Dieting should only be undertaken as a permanent
    life-style change because "yo-yo dieting" is
    associated with an increased incidence of heart
    attacks.

40
IV. STRESS
  • Twenty years ago 60 of heart attack victims
    blamed their attack on stress.
  • It is more socially acceptable to blame stress
    (and it wins more sympathy) than to admit to
    one's eating and smoking habits.
  • Large scale studies of high-level executives have
    not shown an increased incidence of heart
    disease.
  • Prospective studies have failed to show that
    such major life events as "death of spouse",
    "divorce" or "fired from work" are predictors of
    heart disease.

41
  • Nonetheless, people with hypertension show
    greater blood pressure increases in response to
    stress than do people with normal blood pressure.

42
  • Relaxation and meditation can be learned and can
    lower blood pressure.
  • People focusing conscious attention on their
    muscle groups can learn to relax them -- and
    people focusing conscious attention on their
    psychological straining (in meditation) can learn
    to relax that too.
  • Relaxation techniques have been shown to lower
    systolic pressure by 11 mmHg and diastolic
    pressure by 7 mmHg.
  • Even animals can be trained to lower blood
    pressure by use of biofeedback and rewards.

43
V. Salt
  • Although about 20 of the general population
    shows increased blood pressure with increased
    salt, the majority of persons with hypertension
    show a direct relationship between salt intake
    and blood pressure.
  • More precisely, sodium from all sources (salt,
    MonoSodium Glutamate MSG, baking soda,
    antacids, etc.) increases blood pressure in about
    60 of hypertensive persons.
  • The people of northern Japan, with a high-sodium
    diet (which included soy sauce, miso soup and
    pickled vegetables) had a 60 incidence of
    hypertension (the major cause of death was stoke)
    until a community-wide campaign taught people to
    alter their eating habits.

44
  • In the average diet, 77 of sodium comes from
    processed foods, 12 from meat vegetables, 6
    from table salt and 5 from cooking salt.
  • A diet low in potassium or calcium may affect
    blood pressure as adversely as a high sodium
    diet. A banana or an orange provide as much
    potassium as a third of a cup of raisins -- for
    half the calories.
  • Tomatoes are also high in potassium, and a tomato
    can give approximately the same potassium as a
    banana or orange -- for half the calories.

45
VI. CHOLESTEROL
  • Since the blood is 80 water, fats will not
    dissolve in blood.
  • Therefore, fats need to be attached to carrier
    molecules to travel through the bloodstream.
  • The principle carrier molecules for fat are
    albumin, chylomicrons, Very Low Density
    Lipoprotein (VLDL), Low Density Lipoprotein (LDL)
    and High Density Lipoprotein (HDL).
  • Free Fatty Acids (FFAs) are attached to albumin,
    whereas triglycerides are mainly transported by
    chylomicrons and VLDL.
  • Cholesterol and phospholipid are primarily
    transported by LDL and HDL.

46
VI. CHOLESTEROL
  • Free Fatty Acids are a major source of energy for
    many organs, including the heart.
  • Triglycerides are hydrolyzed into FFAs and
    glycerol by the enzyme lipase, which is found
    both inside cells and on the surface of the
    endothelial cells of capillaries.

47
VI. CHOLESTEROL
  • Phospholipid is an essential constituent of cell
    membranes.
  • Cholesterol is also an essential constituent of
    cell membranes, particularly in the nervous
    system.
  • As well, cholesterol is the principal precursor
    of cortisone and sex hormones.
  • Of the cholesterol in the body, 93 is in cells
    and only 7 is in plasma.

48
VI. CHOLESTEROL
  • Cholesterol is supplied to cells primarily by the
    attachment of LDL to specific LDL receptors on
    cell membranes.
  • The Pima Indians of Nevada have diets high in
    fried foods - and have one of the highest obesity
    rates in the world -- yet the high level of LDL
    receptors on their cells leaves them with a heart
    attack rate which is only one-quarter the
    American national average.

49
VI. CHOLESTEROL
  • In the mid-1980s it was established that
  • the condition known as familial
    hypercholesterolemia (seen in less than 1 of the
    population) is the result of a defect in the gene
    responsible for the LDL receptor.

50
VI. CHOLESTEROL
  • Thyroid hormone lowers blood cholesterol by
    increasing the number of LDL receptors on cells.
  • For most people, atherosclerosis due to excessive
    LDL-cholesterol in the blood is the result of a
    high level of dietary saturated fat resulting in
    high LDL-cholesterol production by the liver.

51
VI. CHOLESTEROL
  • The primary function of HDL seems to be to remove
    excess cholesterol from the bloodstream.
  • LDL can directly release cholesterol into
    arterial areas made porous by prostaglandins --
    whereas HDL can scoop-up this loose cholesterol
    and return it to the liver.
  • Thus, HDL deficiency can be as serious an
    atherosclerosis risk as LDL-cholesterol excess.

52
VI. CHOLESTEROL
  • A 1 reduction in blood cholesterol is generally
    associated with a 2 reduction in risk of
    coronary artery disease, within "normal" North
    American levels of blood cholesterol.
  • A one mg/dl (0.26 mmol/Litre) increase in blood
    HDL reduces the risk of coronary artery disease
    by 2 to 3 percent.

53
VII Estrogen
  • Estrogen produced by the ovaries (estradiol)
    increases HDL and reduces LDL, probably by
    increasing the number of LDL receptors in the
    liver (removing LDL from the blood).
  • Estradiol is believed to be the main reason why
    pre-menopausal women have such a lower incidence
    of heart disease than men.

54
  • Men given estrogen therapy had an increase in
    coronary disease mortality.
  • Birth control pills used in the 1980s increased
    the incidence of heart disease due to the
    anti-estrogen effect of synthetic progestin used.
  • Newer synthetic progestins seem to have
    eliminated this problem.

55
Hormone Replacement Therapy
  • HRT with estrogen reduces some of the discomfort
    associated with the onset of menopause (hot
    flashes, vaginal drying thinning and urinary
    tract infections), but was shown in the 1970s to
    increase the risk of endometrial (lining of the
    uterus) cancer by 6-8 times.
  • In 2002 a large-scale study was halted due to
    mounting evidence that HRT combining estrogen
    progestin in women with a uterus (no
    hysterectomy) increased strokes 41, heart
    attacks 29 and breast cancer 26, while reducing
    colorectal cancer 37 and hip fractures 33

56
VIII. DIET
  • Most cholesterol in the blood is manufactured in
    the liver.
  • If dietary cholesterol is too low, the liver
    manufactures more, and if dietary cholesterol is
    too high, the liver manufactures less.
  • But the compensation is not complete, and dietary
    cholesterol does influence levels of cholesterol
    in the blood.

57
  • Cholesterol is found in the tissue of animals,
    not plants -- specifically it is found in the
    muscle portion of meat, not in the fat.
  • Egg yolks and organ meats have about the highest
    cholesterol content of any foods.

58
  • Saturated fats and artificially hydrogenated
    polyunsaturated fats raise blood cholesterol far
    more dramatically than cholesterol itself -- by
    increasing the manufacture of LDL-cholesterol in
    the liver.
  • Animal fat (especially red meat and butter) and
    tropical oils (palm, coconut and chocolate) have
    the most saturated fat.

59
  • Polyunsaturated fat lowers both LDL and HDL
    blood cholesterol, whereas monosaturated fat
    lowers LDL without lowering HDL cholesterol.

60
  • Considering the potential damage due to
    free-radical oxidation by polyunsaturated fat,
    monosaturated fat becomes by far the most
    desirable option -- although reduction of all fat
    is probably the best option of all.
  • Olive oil is 80 monosaturated fat and canola oil
    is 65 monosaturated.

61
  • Because LDL-cholesterol oxidation increases
    atherosclerosis formation, daily doses of the
    antioxidants Vitamin C, Vitamin E and
    beta-carotene reduces heart disease risk.

62
  • In a survey of nearly 90,000 female nurses, those
    in the upper fifth with respect to Vitamin E
    intake had 2/3 the risk of major coronary disease
    as those in the lower fifth.
  • A similar study of nearly 40,000 male health
    professionals showed those consuming over 60 IU
    of Vitamin E daily had less than 2/3 the risk of
    coronary disease as those consuming less than
    7.5 IU daily .
  • Vitamin C helps to regenerate Vitamin E.

63
  • Animals fed fat-free diets display
    deficiency-disease symptoms that are completely
    eliminated by feeding them small quantities of
    the essential fatty acids linolenic, linoleic
    and arachidonic acid, all of which are
    20-carbon-length polyunsaturated fatty acids.
  • These are probably essential for health by being
    precursors of the 20-carbon-length eicosanoids
    (local hormomes)
  • prostaglandins,
  • prostacyclin,
  • thromboxanes, lipoxins and leukotrienes.

64
  • Soluble fiber has been shown to lower blood
    cholesterol.
  • The pectin in apples, pears, oranges, grapefruit
    and bananas is soluble fiber as is the glucan in
    oat bran, peas, beans and whole wheat spaghetti
    and as is the psyllium in the laxative Metamucil.

65
  • Over a six week period, adults with high blood
    cholesterol showed a 16 drop in LDL-cholesterol
    with 57 grams of oat bran daily, and an 11.5
    drop with 85 grams of oatmeal daily.
  • One teaspoonful of Metamucil once or twice daily
    has been shown to reduce cholesterol 5.

66
  • The Omega-3 fatty acids lower blood
    triglycerides, but their main benefit for
    preventing heart disease by being a precursor of
    prostaglandin, which inhibits platelet
    aggregation and dilates blood vessels.
  • Although these fatty acids are present in fish,
    the richest source is linseed (flaxseed) oil,
    which is 55 linoleic acid.

67
  • Nonetheless, the advantages of reduced clotting
    for heart disease may be undermined by the
    dangers of excessive bleeding (especially for
    people at risk of cerebral hemorrhage).
  • Moreover, omega-3 oils in large doses depress the
    immune system and have been associated with
    scarring of heart muscle in animal studies.
  • The main advantage gained by following the
    recommendation to eat fish several times weekly
    may be that it reduces the consumption of animal
    meat.

68
IX. COFFEE AND ALCOHOL
  • Boiled coffee has been shown to increase blood
    cholesterol by 10, whereas filtered-coffee has
    no such effect.
  • The difference is due to "coffee fat" in the
    former, which in purified form can increase blood
    cholesterol dramatically.
  • A study of 1,130 male medical students showed a
    2-3 fold greater risk of coronary artery disease
    among those who drank more than 5 cups of coffee
    per day (the study doesn't reveal whether the
    coffee was boiled or filtered).
  • But the increased cardiovascular risk associated
    with high coffee consumption applied only to
    nonsmokers.
  • Caffeine is known to promote atrial fibrillation
    in some persons.

69
XI. EXERCISE
  • A study of 6,000 San Francisco longshoreman
    showed that light workers had 2.5 times as many
    fatal heart attacks and 3 times the incidence of
    sudden cardiac death as moderate or heavy
    workers.
  • Another study divided 4,000 healthy men aged 30
    to 69 into 4 quartiles by fitness. In the
    subsequent 8 years, the lowest quartile had 8.5
    times the cardiovascular death rate as the
    highest quartile, even after smoking, cholesterol
    and blood pressure were factored-out.
  • In Framingham, the 16 of males and 21 of
    females who lived the most sedentary lives had
    3.5 time the rate of coronary artery disease.

70
  • When a person is at rest or engaged in light
    activity, muscles primarily utilize Free Fatty
    Acids (FFAs) as their energy source.
  • This is an aerobic process (ie, it uses oxygen).
    The term "aerobic" also refers to aerobic
    glycolysis (glucose/glycogen metabolism) as
    opposed to anaerobic glycolysis.
  • Extremely intense and vigorous exertion may place
    demands on muscle that are in excess of those
    which could be met with available oxygen.
  • Nature has provided the mechanism of anaerobic
    glycolysis as a source of spurts of energy that
    are potentially of survival value in critical
    "fight or flight" situations.
  • In a 100-metre dash that takes 10 seconds, 85 of
    the energy is derived anaerobically, a 2-mile
    race lasting 10 minutes would use 20 anaerobic
    energy, and a 60-minute long-distance race would
    use 5 anaerobic energy (95 aerobic energy).

71
  • Anaerobic exertion is intense and short-lived.
  • It produces lactic acid which inhibits enzymes,
    making further exertion difficult.
  • A person will be "winded" until the "oxygen debt"
    is repaid.
  • Anaerobic exertion is not particularly beneficial
    for the cardiovascular system.
  • Sustained, moderately intense exertion that
    allows for high oxygen exchange is very
    beneficial.
  • Aerobic exercise is also of value in eliminating
    fat, because after 10 minutes glycogen stores
    begin to drop, and after 30 minutes most of the
    muscle fuel comes from breakdown of triglycerides
    from fat stores.
  • It is probably good to take anti-oxidants prior
    to aerobic exercise, to reduce resulting
    free-radicals.

72
  • Care should be taken not to begin an exercise
    program that involves excessive exertion which
    the subject is not used-to.
  • A heart attack due to unusual strain defeats the
    purpose.
  • Five minutes of initial stretching is important
    to avoid pulling muscles.
  • A warm-up period avoids initial strain and a
    cool-down period is even more important.
  • Stopping exercising too suddenly can dramatically
    reduce venous return of blood to the heart
    (because muscular contractions propel blood in
    the veins), which can provoke a heart attack if
    the heart's own oxygen needs are not being met.

73
XII. ASPIRIN
  • The main effect of aspirin is to block production
    of the short-acting "local hormone" thromboxane
    -- resulting in reduced platelet aggregation
    (clotting) and reduced artery constriction.
  • This is seemingly of value to prevent heart
    attacks, although it does not seem advisable for
    those at risk of hemorrhagic stroke.
  • In fact, by aspirin use risk of death has been
    reduced 15 among survivors of heart attack,
    stroke, TIA and unstable angina. The benefit of
    aspirin for others is debatable.
  • A well-publicized study of 22,000 American male
    physicians taking 325 mg of aspirin on alternate
    days showed 44 fewer heart attacks, but no fewer
    cardiac arrests or total cardiovascular deaths.
  • A similar study with British male physicians
    taking 500 mg aspirin daily failed to show
    reduction in heart attacks.
  • Both studies showed higher incidence of
    hemorrhagic stroke and bleeding ulcers with
    aspirin.

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XIII. DIAGNOSTIC TOOLS
  • Few people need to wait until a heart attack to
    discover that they have heart problems.
  • Many means of examining the heart are available.
  • ElectroCardioGraphy (ECG) displays the "P-QRS-T"
    waves of heart rhythm.
  • ECG tests are especially effective when done as
    part of an exercise stress test, where the ECG is
    measured while the patient walks at a fast pace
    on a treadmill.
  • An exercise stress test correctly identifies the
    presence of coronary artery disease 70 of the
    time, and correctly identifies the absence of
    coronary artery disease 90 of the time.
  • An exercise stress test can also reveal
    electrical instability in heart rhythms.

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Normal ECG
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  • Chest X-rays can reveal the calcium deposits of
    advanced coronary arteriosclerosis.
  • In radionuclide scanning, a small amount of
    radioactive thallium is injected so that the
    pumping efficiency of the heart can be visualized
    with a Gamma camera.
  • Echocardiography uses ultrasound waves reflected
    (echoed) from the heart to examine functioning
    heart structures, particularly the valves.
  • Computed Tomography (CT, or "CAT scanning") uses
    an X-ray machine that is rapidly rotated around
    someone's body to produce computer-constructed
    images of the heart or brain in "slices" (like
    sliced bread).
  • Magnetic Resonance Imaging (MRI) uses magnetic
    fields and radiowaves rather than X-rays to
    produce similar results as CAT scanning.
  • Positron Emission Tomography (PET) visualizes
    tissue metabolism, but it is still too expensive
    to be used in routine medical examinations.
  • Direct assessments of the heart can be made by
    inserting catheters.

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  • People often have myocardial infarctions that
    involve such small portions of the heart that
    they experience no symptoms and are completely
    unaware that it happened.
  • Nonetheless, such an event is often preliminary
    to a more serious heart attack.
  • Damaged heart cells leak enzymes into the
    bloodstream, such as
  • Creatine PhosphoKinase (CPK),
  • Lactic DeHydrogenase (LDH) and
  • Serum Glutamic Oxaloacetic Transaminase (SGOT).
  • Blood Urea Nitrogen (BUN) and creatinine often
    indicate kidney damage due to high blood
    pressure.
  • Blood tests often indicate problems before
    changes are apparent on an electrocardiogram.

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XIV. MEDICAL INTERVENTION
  • Drug therapy can be used to lower cholesterol,
    reduce hypertension and prevent clotting.
  • For patients with serious blockage of the left
    main coronary artery, bypass surgery will
    increase expected 50 survival time from 5 to 10
    years (which can buy time for advances in
    artificial hearts or other alternatives).
  • Coronary angioplasty uses a catheter with a
    balloon tip to mechanically enlarge coronary
    arteries.
  • An atherectomy catheter uses a rotating disk to
    shave-off atheromas.
  • Catheters with laser tips vaporize plaque which
    dissolves in the bloodstream and is eliminated as
    natural body waste.

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  • Pacemakers can be implanted on hearts that do not
    have a well-controlled natural electrical rhythm.
  • External defibrillators can be worn which detect
    heart stoppage or electrical irregularity and
    apply a shock to restart the heart.
  • Fibrinolytics administered within a few hours of
    a heart attack will dissolve clots in the artery.
  • Streptokinase and
  • tissue plasminogen activator (t-PA) are most
    widely used for this purpose.
  • Concomitant injection of heparin seems to enhance
    the effectiveness of these agents.

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For optimal health, health professionals recommend
  • Maintaining a healthy weight, with a body mass
    index (BMI) of 18.524.9.
  • Limiting dietary fat to 30 percent or less of
    total calories10 percent saturated fat, 10
    percent polyunsaturated fat, and 10 percent
    monounsaturated fats. Consumers should be aware
    that ounce for ounce, all sources of fat have
    approximately the same amounts of calories.
  • Limiting saturated fats to 10 percent of
    calories. Saturated fats come primarily from
    animal sources (e.g., high-fat dairy and meats),
    but also are found in coconut and palm oil.

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  • Limiting polyunsaturated fats to 10 percent of
    calories. Polyunsaturated fats come primarily
    from vegetable oils (e.g., corn oil, safflower
    oil).
  • Limiting monounsaturated fats to 10 percent of
    calories. Monounsaturated fats may have a
    protective role in heart disease. Excellent
    sources of monounsaturated fats include olive
    oils, nuts, avocado, and canola oil.
  • Increasing intake of omega-3 fatty acids. Two to
    four grams daily of omega-3 fatty acids may lower
    risk for CVD by reducing blood clotting, making
    platelets less sticky, and lowering
    triglycerides. Patients should inform their
    physician if they are using omega-3 supplements,
    since they may increase the risk of bleeding.
  • Excellent sources of omega-3 include fatty fish
    (such as salmon and sardines), fish oils, and
    flax seed.

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  • Limiting sodium intake to 2,400 milligrams per
    day.
  • Increasing potassium intake to at least 3,500
    milligrams per day.
  • Eating at least five servings a day of fruits and
    vegetables.
  • Eating a plant-based diet consisting primarily of
    whole grains, fruits, and vegetables is also
    recommended.
  • Eating at least 25 grams of fiber daily.
  • Eating 25 grams of soy protein daily.
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