The vortex formation time to diastolic function relation: assessment of pseudonormalized versus normal filling

In early diastole, the suction pump feature of the left ventricle opens the mitral valve and aspirates atrial blood. The ventricle fills via a blunt profiled cylindrical jet of blood that forms an asymmetric toroidal vortex ring inside the ventricle whose growth has been quantified by the standard (dimensionless) expression for vortex formation time, VFT(standard) = {transmitral velocity time integral}/{mitral orifice diameter}. It can differentiate between hearts having distinguishable early transmitral (Doppler E-wave) filling patterns. An alternative validated expression, VFT(kinematic) reexpresses VFT(standard) by incorporating left heart, near “constant-volume pump” physiology thereby revealing VFT(kinematic)'s explicit dependence on maximum rate of longitudinal chamber expansion (E′). In this work, we show that VFT(kinematic) can differentiate between hearts having indistinguishable E-wave patterns, such as pseudonormal (PN; 0.75 < E/A < 1.5 and E/E′ > 8) versus normal. Thirteen age-matched normal and 12 PN data sets (738 total cardiac cycles), all having normal LVEF, were selected from our Cardiovascular Biophysics Laboratory database. Doppler E-, lateral annular E′-waves, and M-mode data (mitral leaflet separation, chamber dimension) was used to compute VFT(standard) and VFT(kinematic). VFT(standard) did not differentiate between groups (normal [3.58 ± 1.06] vs. PN [4.18 ± 0.79], P = 0.13). In comparison, VFT(kinematic) for normal (3.15 ± 1.28) versus PN (4.75 ± 1.35) yielded P = 0.006. Hence, the applicability of VFT(kinematic) for diastolic function quantitation has been broadened to include analysis of PN filling patterns in age-matched groups.