Three-dimensional Speckle Tracking Echocardiography for the Assessment of Left Ventricular Function and Mechanical Dyssynchrony

Objective: Evaluation of left ventricular (LV) function and dyssynchrony is of vital importance. A newly-developed three-dimensional (3D) speckle tracking echocardiography (STE) has the potential to circumvent limitations of two-dimensional STE. Our study was to evaluate LV function and dyssynchrony by 3D-STE.

Methods And Results: Fifty-two non-ischaemic dilated cardiomyopathy patients (DCM) with complete left bundle-branch block and 55 healthy subjects were enrolled. Of these patients, 24 underwent cardiac resynchronization therapy (CRT). 3D-STE was performed before and 1 month after CRT. We measured 3D (3DS), longitudinal (LS), circumferential (CS) and radial (RS) strain of the LV. LV dyssynchrony was evaluated by the standard deviation of time to peak negative value of 3D strain (3DS-SD) and time to reach the minimum regional volume of 16 segments (SDI) related to the heart cycle. DCM patients had significantly lower global 3DS (-17.12 +/- 6.70% vs -38.38 +/- 4.28%, P < 0.01), significantly greater 3DS-SD (11.11 +/- 5.14% vs 4.04 +/- 1.43%, P < 0.01) and SDI (9.69 +/- 4.82% vs 4.23 +/- 1.33%, P < 0.01) than normal volunteers. 3DS, LS, CS, RS had an excellent correlation with LV ejection fraction (LVEF) (r2 = -0.94, -0.91, -0.93, 0.89, respectively, P < 0.01 for all). 3DS-SD correlated well with SDI (ICC = 0.85). For mild, moderate and severe systolic dysfunction, 3DS-SDs were 4.56 +/- 1.53%, 9.87 +/- 2.58%, and 14.55 +/- 4.71%, respectively (P < 0.01) and SDIs were 4.46 +/- 1.27%, 8.19 +/- 2.35%, and 12.83 +/- 4.87%, respectively (P < 0.01), but independently of QRS width. After CRT therapy, global 3DS (-13.12 +/- 2.63% to -14.06 +/- 2.53%, P = 0.025), 3DS-SDs (12.99 +/- 3.92% to 11.53 +/- 4.53%, P = 0.015) and SDIs (10.85 +/- 3.74% to 9.50 +/- 4.63%, P = 0.013) were markedly improved.

Conclusion: When image quality is optimal, 3D STE seems to be a promising approach assessing LV function and dyssynchrony.