Left ventricular rotation and twist assessed by four-dimensional speckle tracking echocardiography in healthy subjects and pathological remodeling: a single center experience.

Background: Left ventricular (LV) twist represents a main aspect of ejection. It is defined as the difference between the apical and basal rotation and can be assessed by speckle tracking echocardiography (STE). Twist may be underestimated when assessed by two-dimensional-echocardiography due to the difficulty of identifying the real apex. Aim of this study was to evaluate the LV twist by means of three-dimensional (3D)-STE and verify if the inclusion of the apex can modify the assessment of the global twist. Methods: LV volume acquisition with a fully sampled matrix array transducer was performed in 30 healthy subjects and 79 patients with cardiomyopathy secondary to different etiologies. Thirty-nine patients had a LV ejection fraction (EF) 50% (Group A), 16 showed an EF between 40 and 50% (Group B), and 24 patients had an EF 40%(Group C). LV rotation was assessed by 3D-STE at basal, medium, apical, and apical-cap levels. Twist was computed considering the apex either at the apical level (TwistApi) or at the apical-cap level (TwistAC). Results: LV rotation resulted to be progressively higher from base to apical-cap (P<0.0001) with a significant difference between the apex and the apical-cap level (6.20 +/- 3.90 degrees vs. 10.23 +/- 7.52 degrees; P<0.001). Such a difference was constantly found in all Groups (P<0.01 for Group A, P<0.05 for Group B and C). TwistApi was also significantly lower than TwistAC both in the overall population (6.2 +/- 3.89 degrees vs. 10.23 +/- 7.51 degrees; P<0.001) and in the different subgroups (Controls: 9.61 +/- 3.39 degrees vs. 13.75 +/- 6.51 degrees; Group A: 10.49 +/- 4.77 degrees vs. 16.37 +/- 8.49 degrees; Group B: 6.67 +/- 3.44 degrees vs. 9.14 +/- 5.55 degrees; Group C: 33 +/- 2.62 degrees vs. 5.26 +/- 3.74 degrees; P<0.05 for all the comparisons). Conclusions: Identification and inclusion of apical-cap is relevant for twist assessment and can be carried out efficiently by 3D-STE. The inclusion of the true apex in the calculation significantly affects the analysis of twist both in normal individuals and patients with different myocardial diseases.