Abstract 365: Mechanical and Hemodynamic Dyssynchrony in Patients With Systolic Dysfunction
Purpose: The relationship of LV myocardial mechanical and hemodynamic synchrony is an area that has not been well studied. The purpose of this study is to assess whether there is mechanical and hemodynamic dyssynchrony in patients with systolic dysfunction using speckle tracking imaging (STI) and 4-D segmental EF recording (GE, Vivid 7) as compared with normal subjects.
Methods: We studied twenty-seven patients with low ejection fraction (<40%) who were compared with fifty-two age and sex-matched normal subjects. For each subject, the short axis view at three cross section levels, mitral, papillary muscle and apex were chosen for STI. The radius strain and rotation from six segments in each cross section were detected, respectively. The mean and SD of strain peak time index (SPTI, the percentage of cardiac cycle) and of rotation peak time index (RPTI, %) in 18 segments were calculated, respectively as myocardial mechanical synchrony. The 3-D LV chamber image was obtained from apical 4-chamber view. The mean and SD of 4-D mini-volume time index (VMTI, %) in 16 regions was calculated as hemodynamic synchrony. The SD of each time index was averaged as a systolic dyssynchrony index (SDI) for both groups.
Results: In normal subjects, the peak systolic rotation of LV myocardium occurs in synchrony with the LV minimal volume (41.1±6.6 vs. 40.3±3.8, p = NS) while in patients with systolic dysfunction the time of peak rotation is behind the time of minimal volume (51.8±8.1 vs. 47.1±5.5, p = 0.01).
Conclusions: In patients with systolic dysfunction, the peak rotation occurs significantly later than the segmental volume change, and SDI is considerably wider than that in normal subjects. Thus, the relation of LV myocardial rotation and segmental volume change could provide insight into intra-ventricular dyssynchrony between mechanics and hemodynaics in patients with systolic dysfunction.