Added Value of Rotational Mechanics to Longitudinal Indices in the Risk Stratification of Patients With Left...

In the past, analysis of the rotational mechanics of the left ventricle (LV) has been complicated by a confusing codification system and also because it has been approached independently from myocardial function state. We hypothesized that, once global longitudinal strain (GLS) is altered as early sign of myocardial involvement, rotational mechanics is a determining factor in LV ejection fraction (LVEF) in patients with LV hypertrophy (LVH).

2D-speckle tracking echocardiographic images were used to generate GLS and rotational parameters. Myocardial dysfunction was defined by GLS < 16%. We calculated the "Rotational Gradient" (RG), which is the result of the interaction of basal and apical rotations, whether twist (positive RG value) or rigid rotation pattern (negative RG value). The study included 67 healthy controls and 348 patients with LVH (173 with GLS $\ge$  16%, and 175 with GLS < 16 %). We prospectively evaluated the subjects´ RG values according to GLS and LVEF state.

Unlike patients with GLS $\ge 16\%$ (all with LVEF $\ge$  50%), in patients with myocardial dysfunction (GLS < 16%), RG showed a good relationship with LVEF (r = 0.73; p < 0.001). In these latter patients a smaller RG was associated with a probability of developing LVEF < 50% [OR = 1.25 (95% CI: 1.16-1.35; p < 0.001)], RG $\le$  13.4° predicted a LVEF < 50% [AUC 0.92 (95% CI: 0.87-0.96; p < 0.001), sensitivity 82.5% and specificity 92.5%], and a rigid rotation pattern was associated with the lowest LVEF values.

Rotational mechanics should be interpreted based on myocardial function state. In patients with GLS < 16% a smaller RG is associated with lower LVEF. RG can be used to stratify patients with LVH at risk of heart failure.