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The Cardiovascular System

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					The Cardiovascular System

 Textbook Resource: An Introduction to
    Human Disease, Pathology and
 Pathophysiology Correlations, 7th Ed.
        By Leonard V. Crowley
     Congenital Heart Disease
• These are defects of the heart in into which a
  patient is born. Valves or heart chambers are
  structurally unsound. Sometimes these
  conditions are the result of infection in utero as
  in the case of German measles infection. Others
  are the result of malpositions of the fetus,
  intrauterine injuries, and chromosomal
  abnormalities. Some congenital heart diseases
  may be corrected by surgery. Other
  abnormalities may cause little variation from
  normal living while others cause rapid death.
       Valvular Heart Diseases
•   Rheumatic Heart Disease
•   Non-rheumatic Aortic Stenosis
•   Mitral Valve Prolapse
•   Serotonin Related Heart Valve Damage
•   Infective Endocarditis
             Rheumatic Fever
• This is not an infection, but it is a hypersensitivity
  immune reaction brought about because of
  group A beta hemolytic Streptococcus infection.
  Antibodies to the streptococcus cross react with
  the person’s own tissues. Patients with this
  disease have arthritic symptoms in joints along
  with inflammation of the heart. Scarring of the
  heart can lead to heart complications like valve
  stenosis and eventual heart failure. Persons with
  rheumatic fever are given prophylactic penicillin
  therapy to prevent further infection and
  subsequent hypersensitivity response.
  Nonrheumatic Aortic Stenosis
• The aortic valve usually has three cusps, but in
  people with nonrheumatic aortic stenosis, the
  valve has two cusps. Opening and closing of the
  defective valve causes thickening, rigidity, and
  calcification of the valve. The strain associated
  with constricted blood flow causes ventricular
  hypertrophy and eventual heart failure.
  Treatment may require replacing the defective
  valve with an artificial valve. Risk factors
  associated with increased chance of aortic
  stenosis are hypertension, high cholesterol, and
  diabetes
        Mitral Valve Prolapse
• Mitral valve prolapse is mitral regurgitation
  or backflow of blood through closed mitral
  leaflets. Many times the disease is caused
  by degenerative connective tissue
  changes of the valve leaflets. This can
  cause strain of the chordae and papillary
  muscles to cause arrhythmia. Prophylactic
  antibiotic therapy is recommended for
  persons with mitral valve prolapse who
  undergo dental or surgical procedures.
   Serotonin-Related Heart Valve
             Damage
• Serotonin is a chemical produced by
  neuroendocrine cells. Excessive levels of
  serotonin (5-hydroxytryptamine) is related to
  types of heart valve destruction through
  overproliferation of valvular related connective
  tissue. Some drugs, like those used in migraine
  treatment and similar to serotonin also cause
  valve defects. The weight loss drugs
  fenfluramine and phentermine were recalled
  because of a link to heart valve damage.
        Infective Endocarditis
• Subacute infective endocarditis is a
  damage to a heart valve because of
  inflammation and infection at the valve.
  Transient bacteria from skin infections,
  tooth extractions, and other minor
  infections are carried to the valve site. This
  causes platelet activation and thrombus
  formation. Thrombi may cause infarcts in
  many different organs.
  Infective Endocarditis cont…
• Acute infective endocarditis occurs when
  highly pathogenic microorganisms in the
  bloodstream infect a normal heart valve.
  Pieces of infected valve often reach the
  pulmonary arteries and lodge in the lungs
  causing pulmonary infarcts and lung
  abscesses. Staphylococci is the usual
  pathogen involved in this type of infection.
  Intravenous drug abusers are at high risk
  for this disease.
      Coronary Heart Disease
• Arteriosclerosis, narrowing of the arteries
  because of accumulations on the vessel wall,
  causes injury to large coronary arteries. Plaque
  accumulations and atheromatous plaques occur
  in the arteries predisposing the vessel to
  thrombus formations and subsequent
  myocardial ischemia and infarcts. Clinical
  manifestation of the disease range from a
  patient being asymptomatic to one or some in
  following manifestations: angina pectoris,
  Prinzmetal’s angina, arrhythmia, cardiac arrest,
  myocardial infarction
             Cardiac Arrest
• Cardiac arrest is the cessation of cardiac
  contractions (asystole) . It is associated
  with coronary disease, shock, trauma,
  drug abuse, respiratory distress, etc.. This
  is a type of heart attack.
        Myocardial Infarction
• Myocardial infarction is the necrosis of
  heart muscle and it too is a type of heart
  attack. Four mechanisms may trigger a
  myocardial infarction in persons with
  coronary artery disease. These are
  coronary thrombosis, hemorrhage into an
  atheromatous plaque, arterial spasm,
  andsudden myocardial oxygen
  requirements.
 Myocardial Infarction Complication
• Arrhythmias- abnormal cardiac rhythms
• Heart failure- loss of normal cardiac function.
• Intracardial thrombi-thrombi form at the ventricular wall
  covering the endocardial surface.
• Pericarditis- fluid accumulation at the pericardial sac.
• Cardiac rupture- blood accumulates through ruptured
  cardiac tissue causing inefficient blood output.
• Papillary muscle dysfunction- the papillary muscles do
  not contract during ventricular systole causing mitral
  valve prolapse
• Ventricular aneurysm- an outward bulging of a healing
  infarct that causes the left ventricle not to contract.
          Electrocardiogram
• A tool to identify myocardial infarction
  occurrences and the severity of the infarct.
  It measures electrical transmissions
  associated with heart contractions.
 Blood Tests to Identify Myocardial
              Infarcts
• The following enzymes in heart muscles
  increase during myocardial infarctions:
  Troponin T, Troponin I, creatinine kinase,
  creatinine kinase isoenzyme test, lactic
  dehydrogenase, myoglobin
            MI Treatments
• Thrombus dissolving drugs are used.
  Streptokinase is commonly used for this
  purpose
• Drugs to reduce platelet aggregations are
  also used. (Aspirin, heparin)
• Methods to restore coronary blood flow
  like angioplasty are also used.
• Pacemakers are also surgically implanted
  for persons with heart blocks.