See this on POCUS? Your differential list just got a lot shorter. Pericardial effusion in cats is uncommon overall, but when present, the underlying cause is very different from dogs. Most cases in cats—approximately 75%—are associated with congestive heart failure (CHF). In contrast, dogs with CHF rarely develop pericardial effusion. Cats with fluid overload often develop a small pericardial effusion when tipping into CHF, so use POCUS to help guide real-time assessment in these cases as well.