[Assessment of cardiac twist in dilated cardiomyopathy using echocardiography velocity vector imaging]

Abstract

Objective: To assess cardiac twist in dilated cardiomyopathy (DCM) patients using echocardiography velocity vector imaging (VVI) and to explore the clinical application value of VVI in evaluating cardiac twist.

Methods: Thirty-three normal subjects and 30 DCM patients were enrolled. Echocardiographs of parasternal left ventricle basal, papillary muscle level and apical short axis plane, apical four-, two-chamber plane were obtained respectively. Systolic maximal rotation degree, peak rotation velocity, circumferential strain (CS), time to peak rotation velocity (TPRV), peak un-rotation velocity of end diastole and end isovolumic relaxation period in subendocardium were measured by VVI software.

Results: (1) In the normal group, left ventricle performed systolic wring motion with counterclockwise rotation at the apex and clockwise rotation at the base as seen from the apex, while with transient counterclockwise rotation at the base and clockwise rotation at the apex in isovolumic relaxation period. The papillary level rotation form was not constant For the dominant rotation action of the apex, the whole cardiac twist form was counterclockwise. (2) Compared with the control group, 4 DCM patients cardiac twist pattern changed: two showed both counterclockwise rotation of the base and the apex, one represented both clockwise rotation of the base and the apex, another performed the base rotated counterclockwise and the apex rotated clockwise. (3) All rotation and twist parameters of other 26 DCM patients decreased, especially at the apical level: LVtw:7.34 degrees +/- 3.65 degrees vs. 17.01 degrees +/- 4.81 degrees, LVtor: (0.09 +/- 0.04) degrees/mm vs. (0.23 +/- 0.06) degrees/mm, torsion rate: (60.23 +/- 23.67) degrees/s vs. (148.24 +/- 56.23) degrees/s, untwisting rate (0.37 +/- 0.19) degrees/m vs. (0.59 +/- 0.33%)/m, basal CS: (-8.09 +/- 2.73)% vs. (-19.49 +/- 5.51)% (P = 0.013), apical CS: (-8.94 +/- 5.90)% vs. (-27.49 +/- 9.53)% (P = 0.000), basal rotation angle: (-3.60 +/- 2.38) vs. (-6.28 +/- 3.05) (P = 0.014), apical rotation angle: (5.80 +/- 3.55) degrees vs. (11.02 +/- 3.33) degrees (P = 0.001). (4) The apical TPRV in DCM group were longer than the control group represented rotational dyssynchrony in DCM patients (400.26 ms +/- 70.15 ms vs 328.13 ms +/- 66.95 ms, P = 0.008). LVtw correlated positively well with EF (r = 0.489, P < 0.05).

Conclusion: (1) Cardiac twist function was diffusely impaired in DCM patients and it contributed to the global cardiac dysfunction. (2) Cardiac twist pattern changed in some of DCM patients. (3) VVI can objectively reflect cardiac twist function in DCM patients.