title: The vortex formation time to diastolic function relation: assessment of pseudonormalized versus normal filling.
abstract: 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, VFTstandard = {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, VFTkinematic reexpresses VFTstandard by incorporating left heart, near "constant-volume pump" physiology thereby revealing VFTkinematic's explicit dependence on maximum rate of longitudinal chamber expansion (E'). In this work, we show that VFTkinematic 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 VFTstandard and VFTkinematic. VFTstandard did not differentiate between groups (normal [3.58 ± 1.06] vs. PN [4.18 ± 0.79], P = 0.13). In comparison, VFTkinematic for normal (3.15 ± 1.28) versus PN (4.75 ± 1.35) yielded P = 0.006. Hence, the applicability of VFTkinematic for diastolic function quantitation has been broadened to include analysis of PN filling patterns in age-matched groups.
authors.affiliation: Department of Biomedical Engineering, School of Engineering and Applied Science, Washington University in St Louis St. Louis, Missouri.
authors.forename: Erina
authors.initials: E
authors.lastname: Ghosh
authors.affiliation: Department of Biomedical Engineering, School of Engineering and Applied Science, Washington University in St Louis St. Louis, Missouri ; Cardiovascular Biophysics Laboratory, Cardiovascular Division, Department of Internal Medicine, School of Medicine, Washington University in St Louis St. Louis, Missouri.
authors.forename: Sándor J
authors.initials: SJ
authors.lastname: Kovács
keywords: Diastolic function; tissue Doppler imaging; transmitral flow; vortex formation