Early effect of essential hypertension on the left ventricular twist-displacement loop by two-dimensional ultrasound speckle tracking imaging

Abstract

Objective: To investigate two-dimensional (2D) ultrasound speckle tracking imaging (STI) in the evaluation of the early changes in the left ventricular (LV) twist-displacement loop in patients with hypertension (EH).

Methods: Sixty-five EH patients with left ventricular normal geometry (LVN) - including 33 cases with non-left atrial enlargement (NLAE) and 32 cases with left atrial enlargement (LAE) - along with 45 healthy individuals were enrolled in this study. Basal and apical 2D LV short-axis images were acquired and analyzed to obtain the LV rotation (LVrot) and LV radial displacement. Once the LV twist and LV radial displacement were calculated, an LV twist-displacement loop was constructed. Group comparisons between peak twist (Ptw), twist at mitral valve opening (MVOtw), untwisting rate (Utw R), systolic radial displacement (SD), systolic slope (SS), isovolumic relaxation radial displacement (IVRD) and isovolumic relaxation slope (IVRS) were performed.

Results: (1) The Ptw and MVOTw were greater in the NLAE and LAE groups when compared to the normal group while the UTw R was lower in likewise comparison. (2) The LV twist was correlated to the radial displacement in systole and in the isovolumic relaxation period. The SS and IVRS were greater in the NLAE and LAE groups when compared to the normal group.

Conclusions: The LV twist-displacement loop can be reconstructed noninvasively by 2D ultrasound STI. EH affects the systolic and early diastolic component of the twist-displacement loop by increasing the LV twist and decreasing the LV untwisting respectively impairing LV relaxation. The assessment of the LV twist-displacement loop may be useful in the evaluation of early features of LV dysfunction in EH patients.

Keywords: echocardiography; hypertension; left ventricular twist; speckle tracking imaging.