Clinical Resources

Gorlin Formula

Invasive Hemodynamic Valve Area Calculation

Calculates valve area from cardiac catheterization data using transvalvular gradient, cardiac output, heart rate, and flow period. Gold standard for invasive valve assessment.

e.g. 5.0
Aortic SEP: 0.25–0.35s · Mitral DFP: 0.3–0.5s

Formula

Flow = CO × 1000 / (HR × Flow Period)
Valve Area = Flow / (C × √(Mean Gradient))
C = 44.3 (aortic) or 37.7 (mitral)

Severity Thresholds

  • Aortic: Severe <1.0 cm², Moderate 1.0–1.5 cm², Mild >1.5 cm²
  • Mitral: Severe <1.0 cm², Moderate 1.0–1.5 cm², Mild >1.5 cm²

Reference

Gorlin R, Gorlin SG (1951) — Hydraulic formula for calculation of the area of the stenotic mitral valve, other cardiac valves, and central circulatory shunts. Am Heart J. 41:1–29.