Quantitative analysis of intraventricular blood flow dynamics by echocardiographic particle image velocimetry in patients with acute myocardial infarction at different stages of left ventricular dysfunction
Aims Left ventricular (LV) diastolic filling is characterized by the formation of a vortex that supports an efficient transit into
systolic ejection. Aim of this study was to assess the intraventricular (IV) blood flow dynamics among patients with ST elevated myocardial infarction (STEMI) at different degrees of LV dysfunction, in the attempt to find novel indicators
of LV pump efficiency.
Methods
and results
Sixty-four subjects, 34 consecutive STEMI patients and 30 healthy controls, underwent before hospital discharge 2D
speckle tracking echocardiography toassess global longitudinalstrain (GLS), and echo-particle image velocimetryanalysis
to assess flow energetic parameters. Left ventricular volumes ejection fraction (LVEF) and global wall motion score index
(GWMSI) were evaluated by 3D echocardiography. ST elevated myocardial infarction patients were subdivided into
three groups according to LVEF. Energy dissipation, vorticity fluctuation, and kinetic energy fluctuation indexes, which
characterize the degree of disturbance in the flow, exhibit a biphasic behaviour in STEMI patients when compared
with controls, with the highest values in patients with still preserved LV function and progressive lower values with LV
function worsening. Significant linear correlations were found between energy dissipation index and both LVEF and
GLS (r ¼ 0.57, P , 0.001 and r ¼ 20.61, P ¼ 0.001, respectively). Kinetic energy fluctuation index significantly correlates
with both LVEF (r ¼ 0.75, P , 0.001) and GLS (20.58, P ¼ 0.002). Finally, a significant correlation was observed
between GWMSI and energy dissipation index (20.56, P ¼ 0.008).
Conclusions The present study describes, for the first time, the progression of IV flow energetic properties in patients with acute myocardial
infarction at different stages of LV dysfunction when compared with healthy controls. Further data are needed to assess the role of these parameters in the development and maintenance of LV dysfunction.