Assessment of left and right ventricular rotational interdependence: A speckle tracking echocardiographic study

OBJECTIVE: We sought to investigate the possible interdependence of the left (LV) and right ventricular (RV) rotational mechanics. BACKGROUND: Although myocardial fiber architecture and the effect of various pathologic conditions on LV torsional mechanics have already been investigated through multiple studies using different methods, there is still a significant debate about the actual presence and functional significance of RV rotational mechanics. METHODS: We perform a cross-sectional prospective study of 118 subjects, including 19 normal subjects (NS, 35\ub17 years), 34 patients with severe aortic stenosis (AS, 44\ub116 years), 26 patients with nonobstructive hypertrophic cardiomyopathies (HCM, 46\ub118), and 39 patients with nonischemic dilated cardiomyopathies (DCM, 39\ub113 years). LV and RV rotational parameters were measured using velocity vector imaging. Total LV and RV apical segment rotations as well as the rotation of the free wall of RV apex were measured separately. Interdependence of the LV and RV rotational mechanics was assessed using the Spearman rho test. RESULTS: Both LV (7.3\ub0\ub14.1\ub0 in NS, 11\ub0\ub14.6\ub0 in AS, 7.7\ub0\ub15.2\ub0 in HCM, and 1.9\ub0\ub12\ub0 in DCM, P=<.0001) and RV apexes (4.7\ub0\ub12\ub0 in NS, 6.1\ub0\ub14\ub0 in AS, 3.2\ub0\ub13.7\ub0 in HCM, and 2.4\ub0\ub13.6\ub0 in DCM, P=<.0001) rotated counterclockwise in all the four study groups. Interventricular apical rotation interdependence was stronger in the AS (Spearman rho [\u3c1]: .716; P=.000) and in the HCM (\u3c1: .395; P=.04) subgroups than in the NS (\u3c1: .26; P=.27) and DCM (\u3c1: .215; P=.18). In DCM patients, RV apex rotation appeared to be independent of LV rotation. RV free wall apical rotation was larger than its corresponding value for the total apical segments in all studied groups. This difference was significant only in the AS (P=.007). CONCLUSION: Our findings demonstrated a close correlation between RV and LV apical rotation parameters in different cardiac conditions as well as in normal subjects. However, in DCM patients, we also showed some independent rotation of the RV from the LV apex