**Abstract**

Pericardial disease in dogs is relatively uncommon, but its presence may be life-threatening. It is an incidental finding or manifestation of a systemic or cardiac disease. The spectrum of pericardial effusions ranges from mild asymptomatic effusions to cardiac tamponade. Pericardial effusion in dogs has an overall prevalence of 0.43% in general and occurs in approximately 7–10% of the dogs with clinical signs of cardiac disease. More commonly seen in dogs, the clinical signs of pericardial disease can be easily overlooked or mistaken for those of other disease processes. In patients with life-threatening pericardial effusion, which has led to cardiac tamponade, it is important to rapidly identify and treat the elevated intrapericardial pressure. Management is guided by the haemodynamic impact, size, presence of inflammation (i.e. pericarditis), associated medical conditions, and the aetiology whenever possible. In this chapter, pericardial effusion in dogs is emphasized.

**Keywords:** dogs, pericardial effusion, aetiology, pathophysiology, clinical signs, diagnosis, pericardiocentesis, management of pericardial effusion
