Download LWW PPT Slide Template Master

Chapter 24
Disorders of Cardiac Function
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Definition and Functions of the
Pericardium
• Definition
– A double-layered serous membrane surrounding the heart
• Functions
– Isolates the heart from other thoracic structures
– Maintains its position in the thorax
– Prevents it from overfilling
– Contributes to coupling the distensibility between the two
ventricles during diastole; they both fill equally
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Types of Pericardial Disorders
• Pericardial effusion
– The accumulation of fluid in the pericardial cavity
• Cardiac tamponade
– Slow or rapid compression of the heart due to
accumulation of fluid, pus, or blood in pericardial sac
• Pericarditis
– An acute inflammatory process of the pericardium
– Can be acute, chronic, or constrictive
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Types of Pericardial Disorders (cont.)
• Constrictive pericarditis
– Calcified scar tissue develops between the visceral
and parietal layers of the serous pericardium
– Cardiac output and cardiac reserve become fixed
– Ascites, pedal edema, dyspnea on exertion, fatigue,
and the Kussmaul sign
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Clinical Manifestations
• Acute pericarditis is based on clinical manifestations
– ECG, chest radiography, and echocardiography
– Friction rub
• Chronic pericarditis
– No pathogen identified
– Autoimmune disorders
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Coronary Circulation
• Left main coronary artery
• Left anterior descending artery
• Circumflex branch
• Right coronary artery
• Posterior descending artery
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Coronary Heart Disease
• Impaired coronary blood flow that may cause:
– Angina
– Myocardial infarction or heart attack
– Cardiac arrhythmias
– Conduction defects
– Heart failure
– Sudden death
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
• Which of the following conditions will result in
pathological changes arising from pulseless electrical
activity?
a. Pericardial effusion
b. Cardiac tamponade
c. Pericarditis
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
a. Pericardial effusion
b. Cardiac tamponade: Cardiac tamponade is the result of
restricted movement of the muscle and will inhibit
ventricular contraction. The conduction is intact, but
there will be little or no SV.
c. Pericarditis
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
The Evaluation of Coronary Blood Flow
and Myocardial Perfusion
• ECG
– Changes in pattern or orientation of wave forms
• Echocardiogram
– M-mode, two-dimensional, Doppler, and esophageal
• Exercise stress testing
– Motorized treadmill and bicycle ergometer
• Nuclear cardiovascular imaging methods
– Myocardial perfusion imaging, infarct imaging, radionuclide
angiocardiography, and positron emission tomography
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Classification of Coronary Heart Disease
• Chronic ischemic heart disease
– Chronic stable angina, silent myocardial ischemia,
and variant or vasospastic angina
• Acute coronary syndromes
– Represent the spectrum of ischemic coronary
disease, ranging from unstable angina through
myocardial infarction
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Types of Angina
• Chronic stable angina
– Associated with a fixed coronary obstruction that
produces a disparity between coronary blood flow
and metabolic demands of the myocardium
• Stable angina
– The initial manifestation of ischemic heart disease in
approximately half of people with CHD
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Populations Affected by Silent Myocardial
Ischemia
• Persons who are asymptomatic without other evidence of
CHD
• Persons who have had a myocardial infarct and continue
to have episodes of silent ischemia
• Persons with angina who also have episodes of silent
ischemia
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Nonpharmacologic Treatment of Angina
• Smoking cessation in persons who smoke
• Stress reduction
• Regular exercise program
• Limiting dietary intake of cholesterol and saturated fats
• Weight reduction if obesity is present
• Avoidance of cold or other stresses that produce
vasoconstriction
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Antiplatelet and Anticoagulant Therapy
• Aspirin
– The preferred antiplatelet agent for preventing
platelet aggregation in persons with CHD
– Inhibits synthesis of prostaglandin, thromboxane A2
• Ticlopidine and clopidogrel
– May be used when aspirin is contraindicated
– Irreversibly inhibits the binding of ADP to its receptor
on the platelets; no effect on prostaglandin synthesis
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Antiplatelet and Anticoagulant Therapy
(cont.)
• Platelet receptor antagonists
– Target a single step in the aggregation process
– Block the receptor involved in the final common
pathway for platelet adhesion, activation, and
aggregation
– Treat acute coronary syndrome
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Determinants of ACS Status
• Persons with an ACS are routinely classified as low risk or
high risk for infarction based on
– Presenting characteristics
– ECG variables
– Serum cardiac markers
– Timing of presentation
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Causes of Unstable Angina
• Atherosclerotic plaque disruption
• Platelet aggregation
• Secondary hemostasis
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Characteristics of Pain Associated With
Unstable Angina
• The pain has a more persistent and severe course and is
characterized by at least one of three features:
1. It occurs at rest (or with minimal exertion) usually
lasting more than 20 minutes (if not interrupted by
nitroglycerin).
2. It is severe and described as frank pain and of new
onset.
3. It occurs with a pattern that is more severe, prolonged,
or frequent than previously experienced.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Basis for Diagnosis of Unstable Angina
• Pain severity and presenting symptoms
• Hemodynamic stability
• ECG findings
• Serum cardiac markers
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Manifestations of ST-Segment Elevation
Acute Myocardial Infarction
• Abrupt onset
• Severe and crushing pain, usually substernal, radiating to
the left arm, neck, or jaw
• Gastrointestinal complaints (nausea and vomiting)
• Complaints of fatigue and weakness
• Tachycardia, anxiety, restlessness, feelings of doom
• Pale, cool, and moist skin
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Factors Determining the Extent of an
Infarct
• Location and extent of occlusion
• Amount of heart tissue supplied by the vessel
• Duration of the occlusion
• Metabolic needs of the affected tissue
• Extent of collateral circulation
• Heart rate, blood pressure, and cardiac rhythm
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Involvement of Heart Muscle in an Infarct
• Transmural infarcts
– Involve the full thickness of the ventricular wall
– Occur when there is obstruction of a single artery
• Subendocardial infarcts
– Involve the inner one third to one half of the
ventricular wall
– Occur more frequently in the presence of severely
narrowed but still patent arteries
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Medical Management Following Infarct
• Thrombolytic therapy
• Revascularization interventions
– Coronary artery bypass grafting (CABG)
– Percutaneous coronary intervention (PCI)
– Atherectomy
• Cardiac rehabilitation programs
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
• Which type of angina is brought about by exercise or
stress?
a. Stable
b. Unstable
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
a. Stable: Stable angina does not present as a problem
until there is an increase in workload.
b. Unstable
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Myocardial Diseases
• Myocarditis
– Inflammation of the heart muscle and conduction
system without evidence of myocardial infarction
• Primary cardiomyopathies
– Heart muscle diseases of unknown origin
• Secondary cardiomyopathies
– Conditions in which the cardiac abnormality results
from another cardiovascular disease, such as
myocardial infarction
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Types of Cardiomyopathies
• Dilated
• Hypertrophic
• Restrictive
• Arrhythmogenic right ventricular
• Peripartum
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiomyopathy Development (American
Heart Association)
• Heterogeneous group of diseases of the myocardium
• Associated with mechanical and/or electrical dysfunction
• Usually (but not invariably) exhibit inappropriate
ventricular hypertrophy or dilatation
• Due to a variety of causes that frequently are genetic
• Cardiomyopathies either are confined to the heart or are
part of generalized systemic disorders.
• Often lead to cardiovascular death or progressive heart
failure–related disability
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Primary and Secondary Cardiomyopathies
• Primary
–
• Secondary
Genetic
–
• Hypertrophic
• Arrhythmogenic right
ventricular
Acquired cardiomyopathies
• Myocarditis
–
• Left ventricular noncompaction –
cardiomyopathy
–
• Inherited conduction system
disorders
Peripartum cardiomyopathy
Stress cardiomyopathy
Alcoholic cardiomyopathy
• Ion channelopathies
–
Mixed cardiomyopathy
• Dilated cardiomyopathy
• Restrictive cardiomyopathy
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Treatment of Cardiomyopathy
• Treatment depends on the type
– Medication
– Implanted pacemakers
– Defribillators
– Ventricular assist devices
– Ablation
– The goal of treatment is often symptom relief, and
some patients may eventually require a heart
transplant.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Predisposing Factors for Endocarditis
• A damaged endocardial surface
• A portal of entry by which the organism gains access to
the circulatory system
– The presence of valvular disease, prosthetic heart
valves, or congenital heart defects provides an
environment conducive to bacterial growth.
– In persons with preexisting valvular or endocardial
defects, simple gum massage or an innocuous oral
lesion may afford the pathogenic bacteria access to
the bloodstream.
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Infective Endocarditis
• Invasion of the heart valves
and endocardium by a
microbial agent
– Formation of bulky,
friable vegetations and
destruction of
underlying cardiac
tissues
– Systemic manifestations
• Streptocococci
• Enterococci
• Haemophilus sp.
• Actinobacillus
actinomycetemcomitans
• Cardiobacterium hominis
• Eikenella corrodens
• Kingella kingae
• Gram-negative bacilli
• Fungi
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Manifestations of Rheumatic Fever
• Acute stage
– History of an initiating streptococcal infection
– Involves mesenchymal connective tissue of the heart,
blood vessels, joints, and subcutaneous tissues
• Recurrent phase
– Extension of the cardiac effects of the disease
• Chronic phase
– Permanent deformity of the heart valves
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Function and Disorders of the Heart
Valves
• Function: promote directional flow of blood through the
chambers of the heart
• Dysfunction results in disorders:
– Congenital defects
– Trauma
– Ischemic damage
– Degenerative changes
– Inflammation
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Disruptions Occurring With Valvular Heart
Disease
• Narrowing of the valve opening so it does not open
properly
– Stenosis
• Distortion of the valve so it does not close properly
– Incompetent or regurgitant valve: permits
backward flow to occur when the valve should be
closed
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Valve Disorders
• Mitral valve disorders
– Mitral valve stenosis
– Mitral valve regurgitation
– Mitral valve prolapse
• Aortic valve disorders
– Aortic valve stenosis
– Aortic valve regurgitation
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Fetal Blood Flow
• Parallel rather than in series
• Right ventricle delivering most of its output to the
placenta for oxygen uptake
• Left ventricle pumping blood to the heart, brain, and
primarily upper body
• Umbilical vein and two umbilical arteries
• Foramen ovale
• Ductus arteriosus
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cyanosis and Shunting
• Defects that increase resistance to aortic outflow
increase left-to-right shunting.
• Defects that obstruct pulmonary outflow increase rightto-left shunting.
• Crying, defecating, or stress of feeding may increase
pulmonary vascular resistance and cause an increase in
right-to-left shunting.
• Resulting cyanosis
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Factors Affecting Postnatal Pulmonary
Vascular Development
• Prematurity
• Alveolar hypoxia
• Lung disease
• Congenital heart defects
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Signs and Symptoms of Childhood
Congenital Heart Disease
• Symptoms associated with altered heart action
• Heart failure
• Pulmonary vascular disorders
• Difficulty in supplying the peripheral tissues with oxygen
and other nutrients
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Kawasaki Disease
• Skin, brain, eyes, joints, liver, lymph nodes, and heart
• Vasculitis in the small vessels; progresses to involve some of
the larger arteries
• Immunologic in origin
– Acute phase: fever, conjunctivitis, rash, involvement of the
oral mucosa, redness and swelling of the hands and feet,
and enlarged cervical lymph nodes
– Subacute phase: defervescence and desquamation
– Convalescent phase: complete resolution of symptoms
until all signs of inflammation have disappeared after
about 8 weeks
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Types of Congenital Heart Defects
• Patent ductus arteriosus
• Atrial septal defects
• Ventricular septal defects
• Endocardial cushion defects
• Pulmonary stenosis
• Tetralogy of Fallot
• Transposition of the great vessels
• Coarctation of the aorta
• Kawasaki disease
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
• Which of the following might result in the development
of a cardiomyopathy?
a. Valvular stenosis
b. Valvular regurgitation
c. MI
d. Ischemia
e. All the above
f. None of the above
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
a. Valvular stenosis
b. Valvular regurgitation
c. MI
d. Ischemia
e. All the above: Any of these conditions can contribute to
the development of a cardiomyopathy.
f. None of the above
Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins