Clinical Presentation, Acute Clinical Response, Drug Tolerability, and Short‐Term Outcome of Cats Treated for Acute Congestive Heart Failure With Pimobendan (2017–2022): 71 Cases

OBJECTIVE: To describe clinical effects, drug tolerability, and short-term outcomes of cats treated with pimobendan (PB) in conjunction with other therapies for acute congestive heart failure (CHF). DESIGN: Retrospective single-center study (2017 to 2022). SETTING: Academic teaching and referral hospital. ANIMALS: Seventy-one cats with acute CHF treated with PB and furosemide. Treatment included dobutamine (DB) in 15 cases. MEASUREMENTS AND MAIN RESULTS: Physical examination results, laboratory results, and radiographic pulmonary infiltrate scoring were assessed in all cats at admission and 24 h later. Respiratory rate and radiographic pulmonary infiltrate scores decreased after 24 h of therapy (p < 0.0001 for both values). Anemia and hypochloremia were more common than azotemia, hyponatremia, and hypokalemia on Day 1. Serum chloride and potassium concentrations decreased, and serum creatinine concentration increased after therapy (p < 0.05), but none of these values was associated with prolonged hospitalization or reduced survival. Cats receiving PB exhibited few adverse clinical signs. Seven of 15 cats (47%) that received concurrent DB therapy were suspected of having adverse effects that responded to decreased dosage or discontinuation of the medication. There was no difference in survival to discharge (p = 0.17) or days of hospitalization (p = 0.78) between cats receiving DB therapy and those that did not. Overall survival to discharge was 76%, and 75% of cats discharged alive were discharged in ≤3 days. CONCLUSIONS: The short-term prognosis for cats treated for acute CHF was good, and PB therapy appeared to be well tolerated. Most cats showed clinical and radiographic improvement in the first 24 h of therapy and were hospitalized for ≤3 days. The addition of DB to therapy in some cats did not alter survival and was associated with adverse clinical signs in 7/15 cats (47%) treated with DB.