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Tetralogy of Fallot (ToF)
CardiovascularAll SpeciesNew
Key Points
  • Tetralogy of Fallot (ToF) is a congenital cardiac defect characterised by 4 abnormalities
    • Ventricular septal defect (VSD)
    • Pulmonic stenosis
    • Overriding aorta
    • Right ventricular hypertrophy
  • These defects result in reduced pulmonary blood flow and right-to-left shunting of deoxygenated blood into the systemic circulation
  • The severity of clinical signs is primarily determined by the degree of pulmonic stenosis
  • It is most commonly seen in dogs (especially Keeshonds, Bulldogs and Terrier breeds)
  • Echocardiography is the best diagnostic tool
  • Treatment focuses on medical management of hypoxia and polycythaemia to improve the patient’s quality of life
    • Surgical correction is very rarely performed in veterinary medicine due to it’s cost and complexity
  • Without treatment, ToF can lead to chronic hypoxia, polycythaemia, hyperviscosity syndrome, right-sided heart failure and a reduced lifespan
Differential Diagnoses
  1. Patent Ductus Arteriosus (PDA)
  2. Pulmonic stenosis
  3. Atrial septal defect
Overview
Aetiology
Clinical Signs
Diagnosis
Treatment
Prevention
Resources
Overview

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Aetiology

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Clinical Signs

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Diagnosis

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Treatment

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Prevention

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Resources

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Educational content only. This factsheet is for general veterinary education and is not a substitute for professional veterinary advice, diagnosis, or treatment. Not for use in an emergency — contact a veterinarian or emergency service. Full disclaimer →