1. What is the Gorlin Formula?

The Gorlin formula is a hemodynamic method used to calculate the area of the aortic valve. It provides an accurate assessment of valve function and is commonly used in cardiology to evaluate aortic stenosis severity.

2. How Does the Calculator Work?

The calculator uses the Gorlin formula:

Where:

• \( AVA \) — Aortic Valve Area (cm²)
• \( CSA \) — Cross-Sectional Area of LVOT (cm²)
• \( VTI_{LVOT} \) — Velocity Time Integral of Left Ventricular Outflow Tract (cm)
• \( VTI_{AV} \) — Velocity Time Integral across Aortic Valve (cm)

Explanation: The formula calculates the effective orifice area of the aortic valve by comparing flow velocities before and across the valve.

3. Importance of Aortic Valve Area Calculation

Details: Accurate AVA calculation is crucial for diagnosing aortic stenosis severity, determining treatment strategies, and timing surgical interventions.

4. Using the Calculator

Tips: Enter CSA in cm², VTI_LVOT in cm, and VTI_AV in cm. All values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the clinical significance of AVA?
A: AVA helps classify aortic stenosis severity: normal (>2.0 cm²), mild (1.5-2.0 cm²), moderate (1.0-1.5 cm²), severe (<1.0 cm²).

Q2: How is CSA typically measured?
A: CSA is calculated from the diameter of the LVOT using the formula: CSA = π × (diameter/2)².

Q3: What are VTI_LVOT and VTI_AV?
A: These are velocity time integrals obtained from Doppler echocardiography, representing the distance blood travels during one cardiac cycle.

Q4: Are there limitations to the Gorlin formula?
A: Accuracy can be affected by irregular heart rhythms, low flow states, and technical measurement errors in Doppler assessment.

Q5: When is this calculation most useful?
A: Particularly valuable in patients with low-flow, low-gradient aortic stenosis where other parameters may be misleading.