Home/Equations/VTI variation (ΔVTI)VTI variation (ΔVTI)EchoEquationVTI variation (ΔVTI)ΔVTI=VTImax−VTIminVTImean×100%\Delta VTI = \dfrac{VTI_{max} - VTI_{min}}{VTI_{mean}} \times 100\%ΔVTI=VTImeanVTImax−VTImin×100%ExplainerRespiratory variation in the LVOT velocity–time integral; a direct stroke-volume surrogate for fluid responsiveness.