Left Ventricular Untwisting Rate by Speckle Tracking Echocardiography

Abstract

Background-Recent studies validated the measurement of left ventricular (LV) untwisting rate (UR) by speckle tracking echocardiography. A few reports suggest that it may provide additional noninvasive insight into LV diastolic function. Methods and Results-Simultaneous echocardiographic imaging and LV pressure measurements (7F Millar catheters)were performed in 8 adult dogs. Loading conditions were altered by caval occlusion, whereas lusitropic state was changed by dobutamine and esmolol infusion. Inferior vena cava occlusion at all experimental stages (baseline, dobutamine, esmolol) led to a significant decrease (PՅ0.01) in LV end-systolic volume (ESV) and a significant increase in UR (Pϭ0.03). The best relation was observed between LV UR and ESV (rϭϪ0.8, PϽ0.001). The clinical study was conducted in 67 patients (age 57Ϯ17 years, 19 women) undergoing simultaneous right heart catheterization and echocardiographic imaging, with 20 healthy subjects as a control group. There were 34 patients with ejection fraction (EF) Ͻ50% (25Ϯ9%), and 33 patients with normal EF and diastolic dysfunction (64Ϯ7%). Patients with LV systolic dysfunction had a significantly lower UR (Ϫ55 /s) in comparison with the control group (Ϫ89 /s) and patients with normal EF (Ϫ104 /s, PϽ0.05), and the determinants of LV UR were twist, ESV, and (r 2 ϭ0.83, PϽ0.001). In patients with diastolic dysfunction and normal EF, twist and ESV were the independent predictors (r 2 ϭ0.71, PϽ0.001). Conclusions-LV UR is reduced in patients with depressed EF, but not in those with diastolic dysfunction and normal EF, and is primarily determined by twist and ESV.

Echocardiographic evaluation of diastolic heart failure

“…Speckle tracking is the preferred technique given its angle independence and higher reproducibility; however, studies utilising this modality have demonstrated incongruent results. Wang, et al 157 demonstrated that in HF patients, LV twisting and untwisting rates were reduced in patients with reduced LVEF but not in those with HFNEF. The onset of untwisting was significantly delayed in both systolic and diastolic HF.…”

Hypertension and heart failure: a dysfunction of systole, diastole or both?

“…61,62 This may be related to an increased interstitial collagen with lack of change in the MMP-1/TIMP-1 ratio and a higher ratio of shorter (stiffer) N2B isoform to longer (more compliant) N2BA titin isoform, a giant sarcomeric cytoskeletal protein that extends from the Z-lines to the centre of the thick filament and functions as a molecular spring, contributing to the high resting passive stiffness of the myocardium 63,64 and perhaps to the higher restoring forces and preservation of untwisting of the LV (see below). 65 Does HHD evolve as concentric LVH with HFNEF and transition to SHF with LV dilation and reduced EF?…”

The effect of myocardial fibrosis on left ventricular torsion and twist in patients with non-ischemic dilated cardiomyopathy

“…Potential energy stored by LV twist during the systolic phase is rapidly released during LV untwisting and constitutes an important determinant of diastolic suction and function [5]. Two-dimensional speckle tracking imaging (2D--STI) is a novel ultrasound technique for quantification of LV regional deformation, myocardial rotation, torsion, twist and untwisting [6,7]. This technique has been validated by tagged magnetic resonance imaging, which is currently considered gold standard for the assessment of myocardial rotational parameters [8,9].…”