We developed and validated a closed loop lumped parameter cardiovascular model incorporating a regurgitant pathway across the mitral valve and left ventricular outflow tract dynamics to simulate mitral regurgitation (MR) and quantify its effects on forward stroke volume and forward ejection fraction. MR is a common valvular disorder in which preserved ejection fraction may mask a significant reduction in forward flow. Validated across a spectrum of MR severities, the model consistently demonstrated that, despite preserved total stroke volume and conventional EF, both forward stroke volume and forward ejection fraction declined markedly as regurgitation increased. These results accurately replicate the clinical paradox of MR, where standard EF metrics can conceal hemodynamic compromise. By providing direct quantification of forward output, this framework offers a physiologically faithful tool for assessing true hemodynamic burden in MR. It underscores the limitations of traditional EF based assessment and highlights LVOT based flow metrics as more reliable indicators for clinical evaluation and treatment planning in MR.

The authors have declared no competing interest.

This study did not receive any funding

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