Abstract 14603: Left Ventricular Vortex Ring Formation Mapped in Human Hearts by High Resolution Echo Contrast Particle Imaging Velocimetry: Relationship to Myocardial Deformation and Dyssynchrony
Background: Left ventricular (LV) vortex rings serve as kinetic energy reservoirs; however, their interaction with LV wall motion has not been well defined. This study explored the sequence of LV vortex ring formation and their relationship with the magnitude and synchrony of LV longitudinal, circumferential and radial deformation in human hearts.
Methods: High temporal resolution echo contrast particle image velocimetry (158–252 frames/sec) was performed in 43 subjects (65 ± 11 years, 25 males), including 18 normal controls and 25 patients with LV systolic and/or diastolic dysfunction (ejection fraction: 46 ± 17%). The strength of blood flow rotation was defined as phase averaged LV vorticity (Figure A-D) and correlated with the magnitude of global LV longitudinal strain (LS), circumferential strain (CS), and radial strain (RS). Time to peak LS, CS and RS and their standard deviations (STDEV) were determined from18 segments for defining LV synchrony.
Results: For both groups, blood flow vorticity was significantly higher during isovolumic contraction than in early or late diastole (11.3 ± 3.3 s−1 vs. 8.8 ± 2.1 s−1 vs. 9.2 ± 2.8 s−1, P < 0.001) and correlated with endocardial LS (R = -0.45, P = 0.002), CS (R = -0.46, P = 0.002), and RS (R = 0.46, P = 0.002). The STDEV of time to peak LS was prolonged in the presence of LV dysfunction (43 ± 17 ms vs. 64 ± 33 ms, P = 0.004) and correlated with flow vorticity during isovolumic contraction and late diastole (R = -0.57, P = 0.002; R = -0.44, P = 0.02, respectively). On multivariable regression, isovolumic vorticity was an independent determinant of the STDEV of time to peak LS (R2=0.38, P = 0.005).
Conclusions: LV mechanical function is associated with the intracavitary sequence of blood flow vortex ring formation. Blood flow vorticity during isovolumic contraction may be a novel integrated marker of the magnitude and synchrony of LV contraction.
- © 2010 by American Heart Association, Inc.