Using esmolol to treat fast heart rates in dogs and cats

Abstract

OBJECTIVE: To describe the indications and clinical response for dogs and cats treated with esmolol. DESIGN: Retrospective case series from 2003 to 2020. SETTING: Single university veterinary teaching hospital. ANIMALS: Twenty-two dogs and 6 cats. INTERVENTIONS: Animals received either a bolus or bolus and continuous rate infusion of the ultrashort-acting beta receptor antagonist, esmolol. MEASUREMENTS AND MAIN RESULTS: Twenty-two animals were treated for either a supraventricular or sinus tachycardia, 5 were treated for a ventricular tachycardia, and 1 was treated for atrial fibrillation. Esmolol was most frequently used in dogs (N = 9) who had ingested a toxin such as albuterol, amphetamine, or chocolate. Esmolol was administered at median bolus dose of 330 µg/kg (range 10-1000 µg/kg) and continued as a continuous rate infusion in 15 animals at a median dose of 50 µg/kg/min. Defining success as a reduction in heart rate of 20% or greater, esmolol therapy was considered successful in 13 of 28 animals (46%). Animals treated for a toxicosis were more likely to have a successful rate reduction than those treated for other causes (P = 0.006). Nineteen animals survived to discharge. Both treatment success (P = 0.046) and treatment for a toxicosis (P = 0.003) were associated with survival. CONCLUSIONS: Esmolol administration was well tolerated by dogs and cats with tachycardia due to intoxication. Heart rate reduction by at least 20% was achieved in 46% of cases. Animals with toxin ingestion were more likely to be discharged from the hospital.