cardiac tamponade; pericardial tamponade

Introduction

Heart failure secondary to compression of cardiac chambers by fluid within the pericardial space.

Etiology

• pericarditis of any cause including cardiac surgery
• viral & neoplastic forms of pericarditis most common
  • metastatic lung cancer & breast cancer most common
• type A aortic dissection
• blunt trauma to the chest

Epidemiology

slightly more common in men than women

Pathology

• accumulation of fluid within the pericardial space
• increased intrapericardial pressure
• compromised ventricular filling
• diminished cardiac output
• elevated pulmonary venous pressure
• as little as 30 mL in the pericardial sac can cause pericardial tamponade

Clinical manifestations

• Beck's triad
  • distended neck veins (jugular venous distension)
    • may be absent in patients with hypovolemia
  • distant heart sounds (muffled heart sounds)
  • hypotension
• sinus tachycardia
• dyspnea, sinus tachypnea, orthopnea, clear lungs
• abrupt onset
• elevation of central venous & jugular venous pressure
  • no prominent y descent
  • prominent x descent
• narrow pulse pressure
• pulsus paradoxus is common
• hepatic congestion
• evidence of poor peripheral perfusion
• pulseless electrical activity

Laboratory

• serum tropnonin I
  • cardiac-specific troponin-I, elevated in patients with myocardial infarction & cardiac trauma
• serum B-type natriuretic peptide is normal or low
• serum creatinine/serum urea nitrogen to assess for uremia
• complete blood count (CBC)
• coagulation panel: assess bleeding risk
• antinuclear antibody assay, erythrocyte sedimentation rate, & rheumatoid factor: nonspecific, but may suggest connective tissue disease as predisposing factor
• HIV testing: 24% of all pericardial effusions may be associated with HIV infection.
• PPD testing: rule out tuberculosis

Diagnostic procedures

• electrocardiogram (EKG)
  • sinus tachycardia
  • low voltage
  • electrical alternans
  • may be read as normal
• transthoracic echocardiography
  • no thickened pericardium
  • no pericardial calcifications
  • pericardial effusion
  • right ventricular size generally small
  • myocardial thickness generally normal
  • right atrial & right ventricular diastolic collapse
  • increased right-sided flow during inspiration
  • respiratory variation of trans-mitral flow
• right heart catheterization
  • elevated, atrial/ventricular equalized diastolic pressure
  • loss of early diastolic filling wave
  • prominent x-descent, blunted y-descent

Radiology

• chest X-ray may show cardiomegaly, water bottle-shaped heart, pericardial calcifications, or evidence of chest wall trauma
• computed tomography & cardiac magnetic resonance imaging may be useful for ruling out mediastinal disease &/or pulmonary disease in patients with large pericardial effusions

Differential diagnosis

• cardiogenic shock
• constrictive pericarditis
  • early diastolic right ventricular collapse, hypotension & tachycardia consistent with pericardial tamponade
• pulmonary embolism
• tension pneumothorax
• advanced hepatic cirrhosis
• aortic rupture (type A aortic dissection)
  • no neck vein distension

Management

• pericardiocentesis
  • echocardiographic guidance
  • blood from pericardium does not clot
  • avoid draining more than 1 liter of pericardial effusion at 1 time
    • prolonged catheter drainage for remaining fluid
    • neoplastic effusion in particular may need prolonged catheter drainage to prevent recurrence
• supportive prior to definitive therapy
  • aggressive administration of IV saline to maintain adequate ventricular filling (first step)
  • inotropic agents
  • preload-reducing agents are *absolutely contraindicated*
    • diuretics
    • nitrates
  • mechanical ventilation exacerbates hemodynamic compromise; avoid if possible
• surgical pericardiotomy
  • preferred mode of drainage for malignant pericardial effusions & for patients with aortic dissection
  • may be done with videothorascopic guidance
  • percutaneous balloon pericardiotomy for patients who as poor surgical candidates
  • pericardial window
• subacute cardiac tamponade with mild hemodynamic compromise may be managed conservatively
  • serial hemodynamic monitoring
  • serial echocardiography
  • mananagement of volume status
  • treatment of causative disorder

More general terms

• hemopericardium
• hemodynamic instability (compromise)

Additional terms

• pericardiocentesis