Detection of dysfunctional mitral valve prostheses (MP) remains complex even though being optimized by considering echocardiographically derived prosthetic effective orifice area (VA). The purpose was to compare VA in MP, calculated by the continuity equation (CE) using peak velocities (CE_Vpeak), mean velocities (CE_Vmean), velocity–time integrals (CE_VTI) and the pressure half time method using 220 ms as constant first (PHT₂₂₀) as well as optimized constants. In 267 consecutive patients with normally functioning MP, we investigated VA within the first postoperative month. With increasing prosthetic sizes, mean VA values also increase in all calculations. The statistical curves demonstrate no significant difference in graphical steepness but show different levels. Comparison of mean VA showed the known systematic higher values of PHT₂₂₀ and significantly decreased results when using CE_VTI. This systematic difference between mean VA applying PHT₂₂₀ versus CE_VTI is approximately 1.0 cm² for all prosthetic sizes. Calculations via CE_Vpeak were close to the results of CE_VTI. CE_Vmean produced values, which graphically correspond to the PHT₂₂₀ curve. Only PHT₂₂₀ detected the constructional equal prosthetic inner ring width between 29 and 31 mm. To compensate the systematic difference between CE_VTI and PHT₂₂₀, an optimized constant of 140 ms was calculated to be applied in PHT (PHT₁₄₀). VA is a robust and, therefore, preferable parameter for investigating MP. If needed, both CE and PHT are applicable with a systematical difference between CE_VTI and PHT₂₂₀. An optimized constant of 140 ms (PHT₁₄₀) should be applied when calculating VA of mitral valve prostheses via PHT.