Abstract
BackgroundTorsion shear angle φ is an important measure of left ventricular (LV) systolic and diastolic functions. Here we provide a novel index utilizing LV normalized torsion shear angle nttttttt left(widehat{varphi}right) ntttttt volume nttttttt left(widehat{V}right) ntttttt loop to assess LV diastolic functional properties. We defined the area within nttttttt widehat{varphi}widehat{V} ntttttt loop as torsion hysteresis area, and hypothesized that it may be an important global parameter of diastolic function. We evaluated the nttttttt widehat{varphi} ntttttt changes to increased nttttttt widehat{V} ntttttt during early diastole nttttttt left(-dwidehat{varphi}/dwidehat{V}right) ntttttt as a potential measure of LV suction.MethodsSixty resistant hypertension patients (HTN), forty control volunteers were studied using cardiovascular magnetic resonance with tissue tagging. Volumetric and torsional parameters were evaluated.ResultsHTN demonstrated concentric remodeling with preserved ejection fraction. HTN had significantly decreased normalized early filling rate, early diastolic mitral annulus velocity and E/A (1.33 ± 1.13 vs. 2.19 ± 1.07, P < 0.0001) vs. control. Torsion hysteresis area was greater (0.11 ± 0.07 vs. 0.079 ± 0.045, P < 0.001) and peak nttttttt -dwidehat{varphi}/dwidehat{V} ntttttt at early diastole was higher (10.46 ± 8.51 vs. 6.29 ± 3.85, P = 0.002) than control. Torsion hysteresis area was significantly correlated with E/A (r = −0.23, P = 0.025). Thirteen HTN patients had both E/A ratio < 1.12 (Control mean E/A-1SD) and torsion hysteresis area > 0.12 (Control mean torsion hysteresis area + 1SD).ConclusionsTorsion hysteresis area and peak early diastolic nttttttt -dwidehat{varphi}/dwidehat{V} ntttttt were significantly increased in hypertensive concentric remodeling. The nttttttt widehat{varphi}widehat{V} ntttttt loop takes into account the active and passive recoil processes of LV diastolic and systolic phases, therefore provides a new global description of LV diastolic function.
Highlights
Torsion shear angle φ is an important measure of left Here we provide a novel index utilizing Left ventricular (LV) normalized torsion shear ventricular angle ðφ^Þ v(LoVlu) msyestÀoV^licÁ and diastolic functions. loop to assess LV diastolic functional properties
The φ^V^ loop takes into account the active and passive recoil processes of LV diastolic and systolic phases, provides a new global description of LV diastolic function
LV mass and LV mass/volume ratio were significantly increased while LVED R/T ratio was significantly decreased in hypertension patients (HTN) vs. controls
Summary
Torsion shear angle φ is an important measure of left Here we provide a novel index utilizing LV normalized torsion shear ventricular angle ðφ^Þ v(LoVlu) msyestÀoV^licÁ and diastolic functions. loop to assess LV diastolic functional properties. Up to 50% of patients with heart failure have predominant diastolic dysfunction in the presence of preserved LV ejection fraction (EF) [2]. Invasive hemodynamic measurements, such as the time constant of relaxation(1), τ, and LV end diastolic pressure. LV twist, measured as the myocardial rotation gradient from the base to apex along a longitudinal axis [6], is an important mechanical property of the myocardium that results from the helical fiber arrangement of LV. Torsional recoil during isovolumic relaxation and early diastole releases the potential energy stored in the deformed matrix during systole [7,8]. Previous work with cardiovascular magnetic resonance (CMR) in an animal model [9] and recently in humans [10], showed that LV early untwist rate correlated closely with τ
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