Abstract 20785: Characterization of Transmitral Vortex Formation Time index in Patients with Varying Grades of Diastolic Dysfunction
Background: Recent investigations suggest that diastolic dysfunction (DD) Results from impairment of left ventricular (LV) contractile capacity that initiate active suction and effective LV filling: Vortex formation time (VFT) represents a fundamental fluid dynamic index that links systole to diastole, and is used as a measure for the overall efficiency of intraventricular blood flow transport. This study explores the relationship between VFT index and the grades of DD assessed in clinical settings using pulsed-wave Doppler indices of mitral inflow and LV filling.
Methods: Echocardiographic data from113 subjects were categorized into four groups of normal control (51), patients with confirmed diagnosis of grade I of DD (14), grade II of DD (26) and grade III-IV of DD (22). VFT index was computed as: VFT=4*EF*(1-β)*α3/π; where “β” is the fraction of stroke volume contributed from the atrial component of LV filling, and “α3” is a non-dimensional volumetric parameter for the LV.
Results: VFT index was 3.74±1.02 in the control group consistent with a range of optimal fluid momentum transfer. VFT was 2.28±0.83 in patients with grade I of DD suggesting loss of suction effect and disruption of the natural transmitral momentum transfer. A VFT of 3.14±1.21 observed in grade II DD suggests transition from a low pressure ventricle to a high pressure atrium. VFT reached its lowest value of 2.13±1.25 in grade III-IV DD suggesting marked attenuation of momentum transfer. Differences in VFT index were found significant among all the studied groups (p<0.0001) as shown in the Figure.
Conclusion: Transmitral vortex formation index integrates global LV systolic and diastolic functions and matches the continuum of DD grades seen in clinical practice.
- © 2010 by American Heart Association, Inc.