 The flow across the aortic valve is calculated by taking the cardiac output (measured in liters per minute) and dividing it by the heart rate (to give output per cardiac cycle) and then dividing it by the systolic ejection period measured in seconds per beat (to give flow per ventricular contraction).formula_2

The Gorlin equation is related to flow across the valve.Because of this, the valve area may be erroneously calculated as stenotic if the flow across the valve is low (i.e.