Pericardial Effusion & Tamponade

Key Features

Essentials of Diagnosis

• Pericardial effusion

  • Clinical impact determined by the speed of accumulation

  • May or may not cause pain

• Tamponade

  • Tachycardia with an elevated jugular venous pressure (JVP) and either hypotension or a paradoxical pulse

  • Low voltage or electrical alternans on ECG

  • Echocardiography is diagnostic

General Considerations

• Pericardial effusion

  • Can develop during any acute pericarditis process

  • Because the pericardium covers the ascending aorta and arch, aortic dissection and/or rupture can lead to tamponade

  • The speed of accumulation determines the physiologic importance of the effusion

    • Because of pericardial stretch, effusions > 1000 mL that develop slowly may produce no hemodynamic effects

    • Smaller effusions that appear rapidly can cause tamponade due to the curvilinear relationship between the volume of fluid and the intrapericardial pressure

• Tamponade

  • Characterized by elevated intrapericardial pressure (> 15 mm Hg), which restricts venous return and ventricular filling

  • As a result, the stroke volume and arterial pulse pressure fall, and the heart rate and venous pressure rise

  • Shock and death may result

Clinical Findings

• Pericardial effusions

  • May be associated with pain if they occur as part of an acute inflammatory process

  • May be painless, which is often the case with neoplastic or uremic effusion

  • Dyspnea and cough are common, especially with tamponade

  • A pericardial friction rub may be present even with large effusions

• Cardiac tamponade

  • Can be a life-threatening syndrome evidenced by

    • Tachycardia

    • Hypotension

    • Pulsus paradoxus (defined as a decline of > 10 mm Hg in systolic pressure during inspiration)

    • Raised JVP

    • Muffled heart sounds

    • Decreased ECG voltage or electrical alternans

  • Other symptoms may result from the primary disease

  • Ventricular filling is inhibited throughout diastole

• Edema or ascites

  • Rarely present in tamponade

  • These signs favor a more chronic process

Diagnosis

Laboratory Findings

• Laboratory tests tend to reflect the underlying processes

Imaging and Diagnostic Studies

• Pericardial effusion

  • Chest radiograph can suggest chronic effusion by an enlarged cardiac silhouette with a globular configuration but may appear normal in acute situations

  • The ECG often reveals nonspecific T-wave changes and reduced QRS voltage

    • Electrical alternans is present only occasionally but is pathognomonic and is believed to be due to the heart swinging within the large effusion

  • Echocardiography is the primary method for demonstrating pericardial effusion and is quite sensitive

    • If tamponade is present, the high intrapericardial pressure may collapse lower pressure cardiac structures, such as the RA and RV

• Cardiac CT and MRI demonstrate pericardial fluid, pericardial thickening, and any associated contiguous lesions within the chest

• Diagnostic pericardiocentesis or biopsy may be indicated for microbiologic and cytologic studies

  • Pericardial fluid analysis is most useful in excluding a bacterial cause and is occasionally helpful in malignancies

  • A pericardial biopsy may be ...