Clinical decision support
Vertebral heart score calculator
Measure cardiomegaly from lateral thoracic radiographs for dogs and cats.
Reference ranges & assumptions
Defaults from Buchanan (J Vet Intern Med 2001). Adjust to match your reference or breed-specific norms.
Safety checks
- This tool supports calculation and education only.
- It does not diagnose, prescribe, or replace current clinical references.
- Verify patient-specific decisions with current cardiology references and clinical judgment.
- Breed-specific variation exists. Adjust interpretation for brachycephalic and giant breeds.
- Poor radiograph technique can falsely elevate or lower VHS.
Basis and limits
- Calculation basis: VHS = long axis (vertebrae) + short axis (vertebrae). Each axis is measured in units of cranial vertebral bodies starting at T4.
- Assumed normals: Dog ~9.7 ± 0.5 vertebrae; Cat ~8.1 ± 0.5 vertebrae. Adjustable in assumptions.
- Cardiomegaly threshold: commonly cited as >10.5 in dogs and >8.5 in cats, though individual references vary.
- Scope: screening tool. Does not replace echocardiography or clinical assessment.
Formula audit trail
1. Long axis = carina to apex measured in vertebral bodies (T4 start).
2. Short axis = widest perpendicular diameter measured in vertebral bodies (T4 start).
3. VHS = long axis + short axis.
4. Interpretation based on species-specific thresholds in the Assumptions panel.
Calculation steps will appear here for verification.