Lesson 15 of 20
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Constrictive Pericardial Disease

  1. Definition:
    Pericardial disease characterized by fibrosis of the pericardium (usually only the parietal pericardium). Usually pericardial fibrosis exists without concurrent pericardial effusion.
  2. Consequence:
    Pericardial fibrosis causes a restriction to the filling of the right ventricle (just like pericardial effusion). As right ventricular filling (diastolic dysfunction) is reduced cardiac output falls and right heart preload increases.
  3. Presenting signs:
    As with cardiac tamponade, dogs present for weakness, exercise intolerance, syncope, abdominal enlargement, dyspnea. Although this disorder can occur a result of previous pericardial disease, most dogs have no history of prior pericardial or cardiovascular disease.
  4. Signalment:
    Middle aged dogs, both sexes equally represented, mainly in large breeds.
  5. Physical examination findings:
    Most of the signs are very similar to pericardial effusion, this is not surprising since both result from right heart failure. Signs include jugular venous distention, hepatomegaly, and ascites. The heart sounds are usually muffled, arterial pulses are weak, and gallop heart sounds are rare.
  6. ECG findings:
    – Low amplitude QRS in 50 %
    – Prolonged P wave duration – frequent
    – Sinus rhythm – typical, often sinus tachycardia
    – Atrial fibrillation – infrequent
  7. Radiographic findings:
    – Absence of a globose heart
    – Variable amount of pleural effusion, although usually absent
    – Mild to moderate cardiomegaly
    – Caudal vena caval enlargement
    – No pulmonary edema
  8. Echocardiographic findings:
    – Absence or minimal pericardial effusion
    – Difficult or impossible to determine that the pericardium is thickened
  9. Presumptive diagnosis:
    Very difficult to make a presumptive diagnosis. Often a default diagnosis for an individual with signs of right heart failure (jugular venous distention, ascites, pleural effusion). Constrictive pericarditis is considered after other causes of right heart failure such as congenital, valvular, myocardial, and respiratory disease (cor pulmonale), heartworm, and pericardial effusion have been excluded.
  10. Definitive diagnosis:
    Cardiac catheterization will demonstrate elevation of pressures and simultaneous equalization of left and right atrial and ventricular pressures.
    Surgical demonstration of pericardial fibrosis and resolution of signs with pericardectomy.
  11. Therapy:
    Subtotal parietal pericardectomy usually without epicardial stripping.
  12. Prognosis:
    Response to surgery is usually excellent. Recurrence may be a concern.