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Cardiac Pathophysiology

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* Restrictive cardiomyopathy Reduced diastolic compliance of the ventricle. C.O. is normal or ; formation of thrombi, dilation of left atrium, ... – PowerPoint PPT presentation

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Title: Cardiac Pathophysiology


1
Cardiac Pathophysiology
2
Pericarditis
  • Often local manifestation of another disease
  • May present as
  • Acute pericarditis
  • Pericardial effusion
  • Constrictive pericarditis

3
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4
Acute Pericarditis
  • Acute inflammation of the pericardium
  • Cause often unknown, but commonly caused by
    infection, uremia, neoplasm, myocardial
    infarction, surgery or trauma.
  • Membranes become inflamed and roughened, and
    exudate may develop

5
Symptoms
  • Sudden onset of severe chest pain that becomes
    worse with respiratory movements and with lying
    down.
  • Generally felt in the anterior chest, but pain
    may radiate to the back.
  • May be confused initially with acute myocardial
    infarction
  • Also report dysphagia (difficulties swallowing),
    restlessness, irritability, anxiety, weakness and
    malaise

6
Signs
  • Often present with low grade fever and sinus
    tachycardia
  • Friction rub (sandpaper sound) may be heard at
    cardiac apex and left sternal border and is
    diagnostic for pericarditis (but may be
    intermittent)
  • ECG changes reflect inflammatory process through
    PR segment depression and ST segment elevation.

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8
Treatment
  • Treat symptoms
  • Look for underlying cause
  • If pericardial effusion develops, aspirate excess
    fluid
  • Acute pericarditis is usually self-limiting, but
    can progress to chronic constrictive pericarditis

9
Pericardial effusion
  • Accumulation of fluid in the pericardial cavity
  • May be transudate
  • May be exudate
  • May be blood
  • Not clinically significant other than to indicate
    underlying disorder, unless
  • Pressure becomes sufficient to cause cardiac
    compression cardiac tamponade

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11
Outcome depends on how fast fluid accumulates.
  • If development is slow, pericardium can stretch
  • If develops quickly, even 50 -100 ml of fluid can
    cause problems
  • When pressure in pericardium diastolic
    pressure, get ? filling of right atrium,
    ? filling of ventricles, ? cardiac output ?
    circulatory collapse.

12
Clinical manifestations
  • Pulsus paradoxus B.P. higher during expiration
    than inspiration by 10 mm Hg
  • Distant or muffled heart sounds
  • Dyspnea on exertion
  • Dull chest pain
  • Observable by x-ray or ultrasound

13
Treatment
  • Pericardiocentesis
  • Treat pain
  • Surgery if cause is aneurysm or trauma

14
Constrictive (chronic) pericarditis
  • Years ago, synonymous with T.B.
  • Today, usually idiopathic, or associated with
    radiation exposures, rheumatoid arthritis,
    uremia, or coronary bypass graft

15
Pathophysiology
  • Fibrous scarring with occasional calcification of
    pericardium
  • Causes parietal and visceral layers to adhere
  • Pericardium becomes rigid, compressing the heart
    ?? C.O.
  • Stenosis of veins entering atria
  • Always develops gradually

16
Symptoms and Signs
  • Exercise intolerance
  • Dsypnea on exertion
  • Fatigue
  • Anorexia

17
Clinical manifestations
  • Weight loss
  • Edema and ascites
  • Distention of jugular vein (Kussmaul sign)
  • Enlargement of the liver and/or spleen
  • ECG shows inverted T wave and atrial fibrillation
  • Can be seen on imaging

18
Treatment
  • Drugs and diet
  • Digitalis
  • Diuretics
  • Sodium restriction
  • Surgery to remove restrictive pericardium

19
Cardiomyopathies
  • Disorders of the heart muscle
  • Most cases idiopathic
  • Many due to ischemic heart disease and
    hypertension.
  • Three categories
  • Dilated ( formerly, congestive)
  • Hypertrophic
  • Restrictive
  • Heart loses effectiveness as a pump

20
Dilated cardiomyopathy
AKA congestive, ? C.O. ? thrombi formation,
slow blood flow ? contractility, and mitral
valve incompetence, arrhythmias
21
  • Treatment relieve symptoms of heart failure,
    decrease workload, and anticoagulants
    transplants

22
Hypertrophic Cardiomyopathy
Often inherited, C.O. is normal,? inflow
resistance, and mitral valve incompetence,
arrhythmais and sudden death.
23
  • Chest pain
  • Dizziness
  • Fainting, especially during exercise

24
  • major cause of death in young athletes who seem
    completely healthy but die during heavy exercise

25
  • The goal of treatment is to control symptoms and
    prevent complications

26
Restrictive cardiomyopathy
Reduced diastolic compliance of the ventricle.
C.O. is normal or? ? formation of thrombi,
dilation of left atrium, and mitral valve
incompetence.
27
Disorders of the Endocardium Valvular dysfunction
  • Endocardial disorders damage heart valves
  • Changes can lead to
  • Valvular Stenosis too narrow
  • Valvular Regurgitation too leaky
  • (or insufficiency or incompetence)

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  • Valves that are most often affected are the
    mitral and aortic valves, but in I.V. drug users
    and in athletes that inject performance enhancing
    drugs, gt 50 involve only the tricuspid valve.
  • Heart Murmur sound caused by turbulent blood
    flow through damaged valves.

30
Both types of valve disorders
  • Cause increased cardiac work, and increased
    volumes and pressures in the chambers.
  • This leads to chamber dilation and hypertrophy.
  • Chamber dilation and myocardial hypertrophy are
    compensatory mechanisms to increase the pumping
    capability of the heart.
  • Eventually, the heart fails from overwork

31
Aortic Stenosis
  • Three common causes
  • Rheumatic heart disease -Streptococcus infection
    damage by bacteria and auto-immune response
  • Congenital malformation
  • Degeneration resulting from calcification

32
Aortic Stenosis
  • Blood flow obstructed from LV into aorta during
    systole
  • Causes increased work of LV
  • ? LV dilation hypertrophy as compensation
  • ? prolonged contractions as compensation
  • Finally heart overwhelmed
  • ? increased pressures in LA, then lungs, then
    right heart

33
Clinical manifestations
  • Develops gradually
  • Decreased stroke volume
  • Reduced systolic blood pressure
  • Narrowed pulse pressure
  • Heart rate often slow and pulse faint
  • Crescendo-decrescendo heart murmur
  • Angina, dizziness, syncope, fatigue
  • Can lead to dysrhythmias, myocardial infarction,
    and left heart failure

34
Mitral Stenosis
  • Most common of all valve disorders
  • Usually the result of rheumatic fever or
    bacterial endocarditis
  • During healing the orifice narrows, the valves
    become fibrous and fused, and chordae tendineae
    become shortened
  • Get decreased flow from LA to LV during filling
  • Results in hypertrophy of LA

35
  • By causing LA to become pump
  • Get increased pulmonary vascular pressures
    pressures increase through LA into lung
  • ?pulmonary congestion
  • ?lung tissue changes to accommodate increased
    pressures
  • ?increased pressure in pulmonary artery
  • ?increased pressure in right heart
  • ?right heart failure

36
Clinical Manifestations
  • Atrial enlargement can be seen on x-ray
  • Rumbling decrescendo diastolic murmur, and
    accentuated first heart sound
  • Dyspnea
  • Tachycardia and risk of atrial fibrillation
  • Other signs and symptoms are of pulmonary
    congestion and right heart failure

37
Aortic Regurgitation
  • Caused by acute or chronic lesion of rheumatic
    fever, bacterial endocarditits, syphilis,
    hypertension, connective tissue disorder
    (e.g.Marfan syndrome) or atherosclerosis

38
  • Reflux of blood from aorta to LV during
    ventricular relaxation.
  • Causes LV to pump more blood w/ each contraction
  • ? LV hypertrophy
  • LV takes on globular shape
  • ? increased pressures in LA, lung, right heart

39
Clinical manifestations
  • Widened pulse pressure
  • Prominent carotid pulsations and throbbing
    peripheral pulses
  • Palpitations
  • Fatigue
  • Dyspnea
  • Angina
  • High-pitched or blowing heart sound during
    diastole

40
Mitral Regurgitation
  • Causes mitral valve prolapse, rheumatic heart
    disease, infective endocarditis, connective
    tissue disorders, and cardiomyopathy
  • Permits backflow of blood from the LV into the
    LA during ventricular systole
  • Loud pansystolic murmur that radiates into the
    back and axilla

41
See the animated
42
  • Causes blood to flow simultaneously to aorta and
    back to LA.
  • Both LV and LA pump harder to move same blood
    twice
  • ?LV hypertrophy and dilation as compensation
  • Compensation works awhile, then see ?C.O.
  • ? heart failure
  • Also ?LA hypertrophy
  • ? increased pressures through lungs ?
    ? pressures in right heart ?right heart
    failure
  • Can see edema, shock

43
Clinical Manifestations
  • Weakness and fatigue
  • Dyspnea
  • Palpitations

44
Mitral Valve Prolapse
  • Cusps of valve billow upward into the LA during
    ventricular systole
  • Mitral regurgitation can occur
  • Most common valve disorder in U.S.
  • Studies suggest an autosomal dominant inheritance
    pattern
  • Many cases completely asymptomatic
  • Regurgitant murmur or midsystolic click

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46
Clinical manifestations
  • Palpitations
  • Tachycardia
  • Light-headedness, syncope, fatigue, weakness
  • Chest tightness, hyperventilation
  • Anxiety, depression, panic attacks
  • Atypical chest pain

47
Management
  • Echocardiography for diagnosis
  • Related to degree of regurgitation
  • Antibiotics before invasive procedures
  • Beta blockers to relieve syncope, severe chest
    pain, or palpitations
  • Avoid hypovolemia
  • Surgical repair

48
General Treatment for Valve disorders
  • Antibiotics for Strep
  • Anti-inflammatories for autoimmune disorder
  • Analgesics for pain
  • Restrict physical activity
  • Valve replacement surgery

49
Heart failure
  • Definition When heart as a pump is insufficient
    to meet the metabolic requirements of tissues.
  • Acute heart failure
  • 65 survival rate
  • Chronic heart failure
  • Most common cause is ischemic heart disease

50
Right heart failure
  • Systemic symptoms
  • Edema, ascites
  • Enlarged liver, spleen
  • Swollen feet, ankles
  • Nausea
  • Swollen internal jugular veins

51
Left hear failure
  • Fluid accumulation in lungs
  • Shortness of breath
  • Orthopnea
  • Coughing, foaming sometimes
  • Tiredness
  • weakness

52
Ischemic Heart Disease
  • Coronary Artery Disease (CAD), myocardial
    ischemia and myocardial infarction are
    progression of conditions that impair the pumping
    ability of the heart by depriving it of oxygen
    and nutrients.

53
Coronary Artery Disease
  • Any vascular disorder that narrows or occludes
    the coronary arteries.
  • Most common cause is atherosclerosis

54
  • The arteries that supply the heart are the first
    branches off the aorta
  • Coronary artery disease decreases the blood flow
    to the cardiac muscle.
  • Persistent ischemia or complete occlusion leads
    to hypoxia.
  • Hypoxia can cause tissue death or infarction,
    which is a heart attack, which accounts for
    about one third of all deaths in U.S.

55
Risk Factors
  • Hyperlipidemia
  • Hypertension
  • Diabetes mellitus
  • Genetic predisposition
  • Cigarette smoking
  • Obesity
  • Sedentary life-style
  • Heavy alcohol consumption
  • Higher risk for males than premenopausal women

56
Myocardial Ischemia
  • Myocardial cell metabolic demands not met
  • Time frame of coronary blockage
  • 10 seconds following coronary block
  • Decreased strength of contractions
  • Abnormal hemodynamics
  • See a shift in metabolism, so within minutes
  • Anaerobic metabolism takes over
  • Get build-up of lactic acid, which is toxic
    within the cell
  • Electrolyte imbalances
  • Loss of contractibility

57
  • 20 minutes after blockage
  • Myocytes are still viable, so
  • If blood flow is restored, and increased aerobic
    metabolism, and cell repair,
  • ?Increased contractility
  • About 30-45 minutes after blockage, if no relief
  • Cardiac infarct cell death

58
Clinical Manifestations
  • May hear extra, rapid heart sounds
  • ECG changes
  • T wave inversion
  • ST segment depression

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Chest Pain
  • First symptom of those suffering myocardial
    ischemia.
  • Called angina pectoris (angina pain)
  • Feeling of heaviness, pressure
  • Moderate to severe
  • In substernal area
  • Often mistaken for indigestion
  • May radiate to neck, jaw, left arm/ shoulder

61
  • Due to
  • Accumulation of lactic acid in myocytes or
  • Stretching of myocytes
  • Three types of angina pectoris
  • Stable, unstable and Prinzmetal

62
Stable angina pectoris
  • Caused by chronic coronary obstruction
  • Recurrent predictable chest pain
  • Gradual narrowing and hardening of vessels so
    that they cannot dilate in response to increased
    demand of physical exertion or emotional stress
  • Lasts approx. 3-5 minutes
  • Relieved by rest and nitrates

63
Prinzmetal angia pectoris (Variant angina)
  • Caused by abnormal vasospasm of normal vessels
    (15) or near atherosclerotic narrowing (85)
  • Occurs unpredictably and almost exclusively at
    rest.
  • Often occurs at night during REM sleep
  • May result from hyperactivity of sympathetic
    nervous system, increased calcium flux in muscle
    or impaired production of prostaglandin

64
Unstable Angina pectoris
  • Lasts more than 20 minutes at rest, or rapid
    worsening of a pre-existing angina
  • May indicate a progression to M.I.

65
Silent Ischemia
  • Totally asymptomatic
  • May be due abnormality in innervation
  • Or due to lower level of inflammatory cytokines

66
Treatment
  • Pharmacologically manipulate blood pressure,
    heart rate, and contractility to decrease oxygen
    demands
  • Nitrates dilate peripheral blood vessels and
  • Decrease oxygen demand
  • Increase oxygen supply
  • Relieve coronary spasm

67
  • Beta blockers
  • Block sympathetic input, so
  • Decrease heart rate, so
  • Decrease oxygen demand
  • Digitalis
  • Vagal effect
  • Calcium channel blockers
  • Decrease force of contraction, decrease blood
    pressure
  • Antiplatelet agents (aspirin, etc.)

68
Surgical treatment
  • Angioplasty mechanical opening of vessels
  • Revascularization bypass
  • Replace or shut around occluded vessels

69
Myocardial infarction
  • Necrosis of cardiac myocytes
  • Irreversible
  • Commonly affects left ventricle
  • Follows after more than 20 minutes of ischemia

70
Structural, functional changes
  • Decreased contractility
  • Decreased LV compliance
  • Decreased stroke volume
  • Dysrhythmias
  • Inflammatory response is severe
  • Scarring results
  • Strong, but stiff cant contract like healthy
    cells

71
Clinical manifestations
  • Sudden, severe chest pain
  • Similar to pain with ischemia, but stronger
  • Not relieved by nitrates
  • Radiates to neck, jaw, shoulder, left arm
  • Indigestion, nausea, vomiting
  • Fatigue, weakness, anxiety, restlessness and
    feelings of impending doom.
  • Abnormal heart sounds possible (S3,S4)

72
  • Blood test show several markers
  • Leukocytosis
  • Increased blood sugar
  • Increased plasma enzymes
  • Creatine kinase
  • Lactic dehydrogenase
  • Aspartate aminotransferase (AST or SGOT)
  • Cardiac-specific troponin

73
ECG changes
  • Pronounced, persisting Q waves
  • ST elevation
  • T wave inversion

74
Treatment
  • First 24 hours crucial
  • Hospitalization, bed rest
  • ECG monitoring for arrhythmias
  • Pain relief (morphine, nitroglycerin)
  • Thrombolytics to break down clots
  • Administer oxygen
  • Revascularization interventions by-pass grafts,
    stents or balloon angioplasty

75
Tetralogy of Fallot
  • Most common cause of blue baby syndrome.
  • Tetralogy of Fallot has four key features.
  • obstruction from the right ventricle to the lungs
    (pulmonary stenosis) are the most important. A
  • Also, the aorta lies directly over the
    ventricular septal defect, overriding aorta B
  • A ventricular septal defect (a hole between the
    ventricles) -- C see next image
  • and the right ventricle develops thickened
    muscle, right ventricular hypertrophy D

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78
Symptoms
  • high pressure from right ventricle related to
    right hypertrophy A and D
  • Mixing of oxygenated and deoxygenated blood (B
    and C)
  • Left to right shunt first (septal defect), then
    right to left shunt when pressure in the right is
    higher than left

79
Treatment
  • Surgery
  • Palliative, not used common now
  • Total repair
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