Coronary arteriovenous malformation in a dog with a complex arrhythmia and hypothyroidism

J Vet Cardiol. 2019 Jun:23:38-44. doi: 10.1016/j.jvc.2019.01.005. Epub 2019 Feb 26.


A four-year-old Japanese Akita was referred for investigation of lethargy, exercise intolerance, and an irregular heart rhythm. He was diagnosed with atrial fibrillation, a complex ventricular arrhythmia, and hypothyroidism. Echocardiography identified a nest of anomalous vessels surrounding the heart and shunting into the pulmonary artery. Computed tomography confirmed a coronary arteriovenous malformation consisting of a coronary-to-pulmonary arterial communication and an associated complex nest of tortuous vessels, which was thought to be an incidental finding. Clinical signs improved with levothyroxine and antiarrhythmic treatment. Describing an unusual coronary artery anomaly as well, this case serves as a reminder to critically evaluate the hemodynamic significance of structural cardiac disease and to screen for systemic disease in patients with arrhythmias.

Keywords: Atrial fibrillation; CT; Cardiac; Fistula; Veterinary.

Publication types

  • Case Reports

MeSH terms

  • Animals
  • Arrhythmias, Cardiac / drug therapy
  • Arrhythmias, Cardiac / veterinary*
  • Arteriovenous Malformations / diagnostic imaging
  • Arteriovenous Malformations / veterinary*
  • Atrial Fibrillation / veterinary
  • Coronary Vessel Anomalies / diagnostic imaging
  • Coronary Vessel Anomalies / veterinary
  • Dog Diseases / congenital
  • Dog Diseases / diagnostic imaging*
  • Dog Diseases / drug therapy
  • Dogs
  • Echocardiography / veterinary
  • Hypothyroidism / drug therapy
  • Hypothyroidism / veterinary*
  • Male
  • Thyroxine / therapeutic use
  • Tomography, X-Ray Computed / veterinary


  • Thyroxine