A nomogram for estimation of the cardiac valve areas.

SINCE the introduction of the formula by Gorlin and Gorlin in 1951,1 the cardiologist has been able to predict cardiac valve areas with considerable accuracy. Although the formula has distinct limitations, particularly in the presence of valvular regurgitation, its application in determining the severity of valvular and outflow tract stenosis has been widely accepted. The mathematics of the formula itself involve the derivation of a square root, two steps in division, and one step in multiplication. Final solution of the equation requires a moderate expenditure of time and invites four opportunities for mathematical error. In order to circumvent these disadvantages and at the same time to enhance the understanding of the relationships between the various factors employed in the formula, a nomogram has been devised.2