Left Atrial Function in Cats with Left-Sided Cardiac Disease and Pleural Effusion or Pulmonary Edema

BACKGROUND: Congestive heart failure (CHF) in cats with left-sided heart disease is sometimes manifest as pleural effusion, in other cases as pulmonary edema. HYPOTHESIS: Those cats with pleural effusion have more severe left atrial (LA) dysfunction than cats with pulmonary edema. ANIMALS: 30 healthy cats, 22 cats with pleural effusion, and 12 cats with pulmonary edema. All cats were client owned. METHODS: Retrospective study. Measurements of LA size and function were made using commercial software on archived echocardiograms. Cases were identified through searches of medical records and of archived echocardiograms for cats with these conditions. RESULTS: There was no difference (P = .3) in LA size between cats with pleural effusion and cats with pulmonary edema. Cats with pleural effusion had poorer (P = .04) LA active emptying and increased (P = .006) right ventricular (RV) diameter when compared with cats with pulmonary edema and healthy cats. Cats that exhibited LA active emptying of <7.9%, total emptying of <13.6% (diameter) or <19.4% (area), or RV diameter of >3.6 mm were significantly (P < .001) more likely to manifest pleural effusion. CONCLUSIONS AND CLINICAL IMPORTANCE: Poorer LA function and increased RV dimensions are associated with pleural effusion in cats with left-sided heart disease.