Canis ISSN: 2398-2942

Pericardium: idiopathic hemorrhage

Synonym(s): Benign pericardial hemorrhage, idiopathic pericardial effusion

Contributor(s): Serena Brownlie, Mark Rishniw, Jill Sammarco


  • Most common form of pericardial disease.
  • Cause: unknown etiology.
  • Develops slowly giving insidious slow progression of clinical signs.
  • Signs: right-sided failure predominate (lower pressure system and thinner walls), apparently acute onset due to cardiac tamponade.
  • Essential to recognize and treat appropriately.
  • Diagnosis: radiography, ultrasonography.
  • Treatment: pericardiocentesis.
    Empirical treatment may result in clinical deterioration and possible death.
  • Prognosis: good if treated appropriately.


Predisposing factors


  • Breed.


  • Pericardial inflammation results in serosanguineous effusion → increased intrapericardial pressure → pressure eventually exceeds diastolic pressures in right atrium/right ventricle → decreased venous return to the heart → decreased ventricular filling/decreased diastolic function (compliance failure) → decreased end-diastolic volumes of all chambers of the heart → poor cardiac output (by the Frank-Starling mechanism) → activated sympathetic nervous system → activated renin-angiotensin-aldosterone system → tachycardia, vasoconstriction and retention of sodium and water → increased preload → increased end-diastolic pressures in atria and increased ventricular filling pressures → backwards heart failure.
  • Right heart is most susceptible (thinner walls and lower pressure system) → right-sided backward heart failure → increased central venous pressure (distended jugular veins, hepatic venous congestion and ascites) → signs of right-sided heart failure predominate → diastolic collapse of the right atrium and right ventricle (cardiac tamponade).
  • If severe or rapid pericardial fluid accumulation, forward failure develops → circulatory collapse.
  • Has been associated with development of mesothelioma Mesothelioma in Golden Retrievers in one study.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Machida N, Tanak R, Takemura N, Fujii Y, Ueno A & Mitsumori K (2004) Development of pericardial mesothelioma in golden retrievers with a long-term history of idiopathic haemorrhagic pericardial effusion. J Comp Pathol 131 (2-3), 166-175 PubMed.
  • Day M J & Martin M W (2002) Immunohistochemical characterisation of the lesions of canine idiopathic pericarditis. JSAP 43 (9), 382-387 PubMed.
  • Stepien R L, Whitley N T, Dubielzig R R (2000) Idiopathic or mesothelioma-related pericardial effusion: clinical findings and survival in 17 dogs studied retrospectively. JSAP 41 (8), 342-347 PubMed.
  • Jackson J, Richter K, Launer D (1999) Thoracoscopic partial pericardectomy in 13 dogs. J Vet Intern Med 13 (6), 529-533 PubMed.
  • Dunning D, Monnet G et al (1998) Analysis of prognostic indicators for dogs with pericardial effusion - 46 cases (1985-1996). JAVMA 212 (8), 1276-1280 PubMed.