Balloon dilation of a perforated cor triatriatum dexter in a Springer Spaniel: anaesthetic management

A four-month-old male Springer Spaniel presented for investigation of ascites of three weeks’ duration. On transthoracic echocardiogram, cor triatriatum dexter was diagnosed with associated right-sided congestive heart failure. Medical therapy consisting of furosemide, spironolactone and benazepril was initiated. On the day of surgery, the dog was premedicated with methadone 0.2 mg/kg intravenously, and general anaesthesia was induced with midazolam 0.2 mg/kg intravenously and propofol 25 mg. Anaesthesia was maintained with isoflurane in oxygen. Concurrently, constant rate infusions of fentanyl 0.2–0.3 µg/kg/minute and lidocaine 50 µg/kg/minute were administered. Ventricular premature complexes and ventricular tachycardia developed during the placement of the catheter and during the first balloon dilation. Antiarrhythmic therapy with lidocaine 2 mg/kg was required. At the end of the procedure, acepromazine 5 µg/kg intravenous and buprenorphine 20 µg/kg intravenous were administered. Recovery from general anaesthesia was uneventful.