Pericardial Diseases reduced Flashcards Preview

The pericardium is a sac surrounding the heart.

1. Two tissue layers:
   • Visceral, a thin tissue-like layer
   • Parietal, a more fibrous, rigid layer
2. Pericardial cavity 
   • holds 20 – 50 ml of pericardial fluid.

Pericardial pressure is similar to pleural pressure varying with respiration between –4 to +4 mm Hg.

1. Prevents infection
2. Lubricates the heart
3. Facilitates motion within the sac
4. Protects the heart from excessive displacement
   •  maintains optimum shape of the heart
5. Applies a compensatory hydrostatic pressure to the heart
   • to compensate for alterations in gravitational force  

Inflammation of the pericardium

Causes:

• infection
  • viral
  • bacterial
  • fungal
  • tuberculous
• myocardial infarction
• trauma/cardiotomy
• metastatic disease
• drugs
• mediastinal radiation
• systemic diseases:
  • Rheumatoid Artheritis 
  • Lupus
  • Scleroderma

1.Sudden onset of severe chest pain exaggerated by inspiration

2.Diffuse ST segment elevation, PR segment depression, T wave inversion

3. Pericardial friction rub

Treatment:

  1.  Salicylates or NSAIDS

  2.  Analgesics (Indomethacin)

  3.  Corticosteroids

Acute pericarditis in the absence of effusion does not alter cardiac function.

Accumulation of pericardial fluid in the pericardial cavity

• Causes:
  •   Idiopathic-unknown cause
  •   Neoplastic
• Diagnosis
  • ECHO - the most useful method for clinical detection of effusion – it is very accurate on estimating effusion size
  • Signs and symptoms depend on the rate of fluid accumulation

    • Acute: _{with an rapid effusion, the pericardium does not have time to accommodate, so intrapericardial pressures increase significantly and cardiac tamponade results - Even small volumes of fluid (100 – 200 ml) that accumulate rapidly will cause cardiac tamponade}

    • Gradual:  _{if the effusion develops gradually, the pericardium stretches to accommodate fluid - A large volume of fluid (up to 1000 ml) can accumulate without a significant increase in pressure}

• Cardiac tamponade exists when an increase in  pericardial pressure impairs diastolic filling of the heart.
• Cardiac filling is related to the diastolic transmural (distending) pressure across each chamber
  • _{Transmural pressure = Pressure within the chamber - extracavity pericardial pressure}
  • _{Any increase in pericardial pressure relative to the pressure within the chamber reduces filling}
• Medical Emergency

1. Increased central venous pressure
2. JVD
3. Equalization of cardiac filling pressures
4. Decreased CO, SV
5. Hypotension
6. Activation of the SNS
7. Tachypnea
8. Muffled heart sounds
9. Decreased voltage on ECG
10. Pulsus paradoxus

removal of fluid

• Pericardiocentesis
• Subxiphod pericardiostomy
• Thoracic pericardiostomy (open or thoroscopic)

• Expand intravascular volume
• Increase myocardial contractility
  • Isoproterenol
• Correct metabolic acidosis
• Can do under local, or with Ketamine

Fibrous scarring and adhesions of the pericardial cavity that creating a rigid, stiff shell around heart that limits filling of the heart

Causes 

• Idiopathic
• Previous cardiac surgery
• Exposure to radiotherapy
• TB

• CVP, RAP, PCWP elevated
• CO decreased
• Fatigue
• Atrial dysrhythmias
• Edema
• Ascites
• Hepatomegaly
• Pulsus paradoxus
• JVD

Surgical stripping and removal of adherent constricting pericardium (pericardiectomy)

1. Minimize changes to HR, SVR, preload, and contractility
   • _{use: ketamine, etomidate, pancuronium}
2. AVOID bradycardia
3. Maintain intravascular volume to AVOID hypotension
   • _{have large bore IV’s, A-line}
4. Blood transfusions may be necessary to treat blood losses associated with pericardiectomy