Left Ventricular Untwist Research Articles

Identification of Novel Independent Correlations between Cellular Components of the Immune System and Strain-Related Indices of Myocardial Dysfunction in CKD Patients and Kidney Transplant Recipients without Established Cardiovascular Disease.

The role of immune system components in the development of myocardial remodeling in chronic kidney disease (CKD) and kidney transplantation remains an open question. Our aim was to investigate the associations between immune cell subpopulations in the circulation of CKD patients and kidney transplant recipients (KTRs) with subclinical indices of myocardial performance. We enrolled 44 CKD patients and 38 KTRs without established cardiovascular disease. A selected panel of immune cells was measured by flow cytometry. Classical and novel strain-related indices of ventricular function were measured by speckle-tracking echocardiography at baseline and following dipyridamole infusion. In CKD patients, the left ventricular (LV) relative wall thickness correlated with the CD14++CD16- monocytes (β = 0.447, p = 0.004), while the CD14++CD16+ monocytes were independent correlates of the global radial strain (β = 0.351, p = 0.04). In KTRs, dipyridamole induced changes in global longitudinal strain correlated with CD14++CD16+ monocytes (β = 0.423, p = 0.009) and CD4+ T-cells (β = 0.403, p = 0.01). LV twist and untwist were independently correlated with the CD8+ T-cells (β = 0.405, p = 0.02 and β = -0.367, p = 0.03, respectively) in CKD patients, whereas the CD14++CD16+ monocytes were independent correlates of LV twist and untwist in KTRs (β = 0.405, p = 0.02 and β = -0.367, p = 0.03, respectively). Immune cell subsets independently correlate with left ventricular strain and torsion-related indices in CKD patients and KTRs without established CVD.

Limitations of Diagnosis of Ischemic Left Ventricular Dysfunction Using the Values of Strain, Twist and Untwist in Patients With Myocardial Infarction of Various Localization.

To compare capabilities for diagnosing regional and global myocardial dysfunction using the values of longitudinal and circular strain, left ventricular (LV) torsion and untwisting in patients with myocardial infarction (MI) of various locations. Patients included in the study (n=121) were divided into three groups: patients with unstable angina (n=30), patients with anterior MI (n=45), and patients with inferior MI (n=46). Clinical, laboratory and instrumental test were performed, including echocardiography. For a quantitative analysis of LV contractility, the maximum systolic peaks of regional and global longitudinal and circular strain, systolic and diastolic rotation, LV torsion and untwisting were measured. Anterior MI was characterized by injury of the LV apical segments, while inferior MI was characterized by injury of the basal segments. In anterior MI, the longitudinal strain was reduced less than 14.5% and circular strain less than 19.3% in the apical segment of the LV anteroseptal wall (ASW). In akinesia of the LV ASW apical segment, longitudinal and circular strains were reduced less than 10%. The magnitude of the circular strain of the LV ASW apical segment (diagnostic threshold 19.3%, sensitivity (Se) 87%, specificity (Sp) 90%) was superior to that of the longitudinal strain as a diagnostic marker for regional ischemic dysfunction in anterior MI. The magnitude of the circular strain of the basal segment of the LV inferior wall in inferior MI has a greater diagnostic value for identifying regional systolic dysfunction than the value of the longitudinal strain of this LV segment. The diagnostic threshold was 17.3%, Se 79%, Sp 80%. A decrease in the circular strain of the LV ASW less than 19.3% in the LV apical segment is more specific (Sp 90%) for diagnosing regional systolic dysfunction in anterior MI than a decrease in longitudinal strain. A circular strain value of less than 17.3% in the basal segment of the LV inferior wall is more specific (Sp 80%) than the longitudinal strain of this segment for diagnosing regional systolic dysfunction in inferior MI. Predominant injury to the LV apex in anterior MI can cause systolic and diastolic myocardial dysfunction, which is manifested by a decrease in LV circular deformation, torsion and untwisting.

Peak apical recoil rate is a simplified index of left ventricular untwist: validation and application for assessment of diastolic function in children.

The use of untwisting rate as a novel index of LV diastolic function in clinical practice has been limited due to its tedious and time-consuming analysis. Therefore, we simplify the untwist measurement by only measuring the LV apex's recoil rate and validating and applying peak apical recoil rate (PARR) as an index of diastolic dysfunction (DD) in pediatric subjects during increased and decreased lusitropic states. We recruited 153 healthy subjects (mean age 13.8 ± 2.9years), of whom 48 performed straight leg raising exercise and an additional 46 patients (mean 8.4 ± 5.6years) with documented pulmonary capillary wedge pressures (PCWP) (validation cohort). In addition, we studied 16 dilated cardiomyopathy patients (mean age 9.5 ± 6.3years) (application cohort). PARR and isovolumic relaxation time (IVRT) were compared to PCWP. Both PARR and PARR normalized by heart rate (nPARR) were excellent in detecting patients with PCWP ≥ 12mmHg and greatly superior to IVRT in this respect (AUC: 0.98, 95% CI [0.96, 1.0] vs. AUC: 0.7 95%CI [0.54,0.86]). In DCM patients, PARR and nPARR were greatly decreased compared to controls (-38.6 ± 18.6º/s vs -63.1 ± 16.3º /s, p < 0.001) and (-0.43 ± 0.20 º/ s/min vs -0.83 ± 0.28º/s/min, p < 0.0001) but increased with straight leg raising exercise (-59.4 ± 19.4º/s vs -97.8 ± 39.0 º/s, p < 0.01) and -0.85 ± 0.36 vs -1.4 ± 0.62 º/s/min (p < 0.0001) respectively. PARR and nPARR successfully detected increased and decreased lusitropic states and superior to IVRT in correlation with PCWP. This highly reproducible parameter offers incremental value over traditional indices of DD and may potentially serve as a useful index of elevated PCWP in children.

Anabolic Steroids Use Is Associated with Impairments in Atrial and Ventricular Cardiac Structure and Performance in Athletes.

Despite potential severe cardiac side effects, anabolic androgenic steroids (AAS) are increasingly used by strength athletes. However, previous echocardiographic studies focused on the left ventricular (LV) strains but did not assess LV twist and untwist mechanics. Moreover, left atrial (LA) function has been often neglected, and its stiffness, an important determinant of LA reservoir function, has never been challenged. The aim of this study was to investigate the effects of AAS on LA and LV morphologies and functions in strength athletes. Fifty subjects including 20 strength-trained young athletes age 32.0 ± 8.5 yr with a mean duration of AAS use of 4.7 ± 1.8 yr (users), 15 athletes with no history of AAS use (nonusers) and 15 sedentary controls underwent speckle tracking echocardiography to assess LA and LV morphology and function. Users showed higher LA reservoir dysfunction than nonusers (33.7% ± 10.9% vs 44.9% ± 9.9% respectively, P = 0.004) and higher LA stiffness (0.13 ± 0.05 vs 0.19 ± 0.08 A.U., respectively; P = 0.02), higher LV mass index and lower global and regional LV diastolic and systolic dysfunction (global longitudinal strain: -15.5% ± 3.2% vs -18.9% ± 1.8% respectively; P = 0.003), with a drop of LV twist-untwist mechanics (untwisting velocity: 61.5°·s-1 ± 20.2°·s-1 vs 73.7°·s-1 ± 16.1°·s-1 respectively, P = 0.04). There were significant correlations between LV mass and LV apical rotation (P = 0.003, r = 0.44) and diastolic longitudinal strain rate (P = 0.015, r = 0.33). Our results showing significant LA and LV remodeling and dysfunctions in young AAS using athletes are alarming. Screening echocardiography based on speckle tracking echocardiography parameters for early diagnosis, as well as a stronger awareness in athletes and in physicians are warranted in this context.

Features of changes in the level of fibrosis markers in lipotoxic myocardial damage in patients with epicardial obesity

Abstract In visceral obesity, lipotoxic myocardial damage develops, which leads to the formation of myocardial fibrosis with impaired diastolic function and the development of heart failure (HF). Currently, the search for markers of early diagnosis of left ventricular (LV) diastolic dysfunction (DD) is relevant. Objective To study the features of changes in the level of fibrosis markers in lipotoxic myocardial damage in patients with epicardial obesity (EO). Materials and methods The study included 125 men with general obesity (BMI average 33.24±3.65 kg / sq. m.). All patients underwent transthoracic echocardiography (ECG) to assess the thickness of epicardial adipose tissue (tEAT) as the equivalent of visceral obesity, as well as to diagnose DD LV. According to the results of echocardiography, the patients were divided into 2 groups: EO(+) with epicardial fat thickness (tEAT) ≥7 mm (n=78); EO(−) with tEAT &amp;lt;7 mm (n=40). DD LV was detected in 7 patients, who were subsequently excluded from the analysis. All patients were assessed for profibrotic markers in the blood serum (MMP-3, collagen I, collagen III, TGF – β, VEGFA, PICP) using enzyme immunoassay. The level of free fatty acids (FFA), as early markers of lipotoxic myocardial damage, was also determined in all patients using enzymelinked immunosorbent assay. The peak untwist ratio LV was studied using speckle-tracking ECG. The exclusive criteria were the presence of coronary pathology, arterial hypertension, type 2 diabetes mellitus, as possible causes of lipotoxic myocardial damage. Results When studying the features of changes in the level of serum markers of myocardial fibrosis, a statistically significant increase in the level of all the studied markers was revealed in the EO(+) group compared to the EO(−) group, and a statistically significant increase in the level of FFA in the EO(+) group compared to the EO(−) group (0.84±0.02 mmol/l and 0.35±0.01 mmol/L, respectively, p=0.02). A statistically significant relationship was found between the levels of FFA and collagen III (r=0.32, p=0.03) and TGF – β (r=0.30, p=0.04). According to the results of speckle-tracking ECG in the EO(+) group, an increase in the rate of LV untwist to −125.56 (−141.0; −117.0) deg/s (p=0.003) was determined. When studying the effect of FFA as a marker of lipotoxic effect on the myocardium, a weak statistically significant relationship was revealed between the level of FFA and the rate of LV untwist (r=0.27; p=0.03) in the EO(+) group, while no such effect was found in the EO(−) group. Conclusion In EO, as a result of neurohumoral disorders, lipotoxic myocardial damage develops and progresses, leading to LV DD, the detection of which is probably possible with the help of the LV unwinding rate. Funding Acknowledgement Type of funding sources: None.

Relationship Between Athlete's Heart And Blunted Left Ventricular Untwist During Orthostasis

It is known that the orthostatic tolerance is attenuated in the endurance athletes (Fit). We have shown that an impaired increase in left ventricular (LV) untwist against the orthostatic stress may be underlying mechanism of orthostatic intolerance in Fit. Although this impaired response of the LV untwist may be related to athlete’s heart, its details are still unclear. PURPOSE: To clarify cardiac function and morphology that would affect LV peak untwisting rate at the pre-syncope. METHODS: Twelve male college level competitive athletes (Fit, 23 ± 8 years old) and 12 male non-athletes (Unfit, 25 ± 5 years old) underwent maximal exercise test on a bicycle ergometer to assess maximal oxygen consumption (VO2max) and graded lower body negative pressure (LBNP) up to presyncope to assess a cumulative stress index (CSI) as a measure of orthostatic tolerance. LV end-diastolic volume/BSA (EDVi), end-systolic volume/BSA (ESVi), torsion, peak untwisting rate and sphericity index (LV length/ LV diastolic internal diameter) were evaluated by 3D speckle tracking echocardiography during the LBNP test. Pearson's correlation analysis was performed between peak untwisting rate and the other parameters of 3D echocardiography at the presyncope. In addition, multiple linear regression was performed between LV peak untwisting rate vs. age and the other parameters of 3D echocardiography. RESULTS: VO2max was higher (59 ± 4 vs. 36 ± 8 ml·kg-1·min-1, p < 0.05) and CSI was lower (1010 ± 472 vs. 1467 ± 596 mmHg·min, p < 0.05) in Fit than in Unfit. LV peak untwisting rate was slower in Fit than in Unfit at the presyncope ( -161 ± 51 vs. -245 ± 88 °/cm, p < 0.05). EDVi (r = 0.50, p = 0.013), ESVi (r = 0.58, p = 0.003), torsion (r = -0.57, p = 0.004) and sphericity index (r = -0.54, p = 0.007) were moderately related to LV peak untwisting rate. In multiple linear regression, torsion (β = -0.454, p = 0.029) and sphericity index (β = -0.454, p = 0.029) were independently correlated with LV peak untwisting rate. CONCLUSION: The more spherical LV was associated with the slower peak untwisting rate at the presyncope. This finding suggests that athlete’s heart is related with blunted increase in peak untwisting rate at the presyncope given that the athlete’s heart is characterized by a spherical shape of the heart.

Left Ventricular Twist and Untwist in Patients Undergoing Elective Percutaneous Coronary Intervention.

Background:Left ventricular (LV) twist and untwist plays important roles in physiological adaptation and development of clinically relevant cardiac diseases.Aims:To assess LV twist and untwist in patients undergoing elective percutaneous coronary intervention (PCI) by two-dimensional (2D) speckle tracking echocardiography (STE).Subjects and Methods:Fifty patients who had stable angina pectoris and/or abnormal result from noninvasive stress tests were enrolled after undergoing elective PCI. Conventional and 2D STE were performed before elective PCI and after 3 months.Results:There was no significant systolic improvement in conventional echocardiography. However, there was a significant diastolic improvement after elective PCI as higher E, E/A, e` and lower E/e` (P < 0.034, <0.042, 0.015, and 0.033, respectively). In addition, there was a statistically significant improvement of STE-derived systolic parameters as regard higher global longitudinal strain, peak twist, and torsion (P value 0.009, 0.009, and < 0.001, respectively). Furthermore, there was significant improvement of STE-derived diastolic parameters as higher peak untwist, recoil, and lower time to peak untwist (P value 0.013, 0.001, and 0.004, respectively).Conclusions:LV and untwist parameters were improved before most of conventional echocardiographic parameters in postrevascularization of stable coronary artery disease.

Reduced Exercise Capacity in Diabetes Mellitus Is Not Associated with Impaired Deformation or Twist

Exercise capacity is frequently reduced in people with diabetes mellitus (DM) and may be due to subclinical cardiac dysfunction. Speckle-tracking echocardiography is now widely available; however, the clinical utility and significance of left ventricular (LV) strain and twist parameters remain uncertain. We hypothesized that LV strain and twist would be reduced in DM subjects during exercise. Adults with type 1 or type 2 DM and age- and sex-matched controls performed cardiopulmonary exercise testing (VO2 peak) and supine bicycle exercise echocardiography. Detailed echocardiographic assessment of biventricular function was performed at baseline and repeated during incremental exercise to maximal intensity. Of the 60 participants completing the study protocol, 51 (34 DM, 17 controls; mean age, 42±13years; 69% male; DM duration, 16±10years) had sufficient image quality to assess LV deformation and twist mechanics at rest. Of these, 38 (25 DM, 13 controls) were able to be assessed immediately after exercise. Baseline LV systolic and diastolic function using standard echocardiography measurements were similar between groups. Resting LV global longitudinal strain, twist, twist rate and untwist rate, and the corresponding peak exercise and reserve measures did not differ significantly. As compared with the control subjects, exercise capacity was reduced in the DM cohort (VO2 peak 33±10 vs 41±12mL/minute/kg; P=.02); however, no correlation was observed between VO2 peak and LV twist reserve (R=0.28, P=.09), LV twist rate reserve (R=0.14, P=.39), or LV untwist rate reserve (R=0.24, P=.14). Despite reduced VO2 peak, LV twist mechanics at rest and after maximal intensity exercise did not differ significantly in a cohort of asymptomatic DM subjects with normal resting LV systolic and diastolic function compared with age- and sex-matched controls. This would suggest that exercise capacity can be reduced in the absence of subclinical cardiac dysfunction and that noncardiac factors should be considered as alternative explanations.

Left ventricular mechanics in late second trimester of healthy pregnancy.

To evaluate left ventricular (LV) mechanics in the second trimester of healthy pregnancy and to determine the influence of underpinning hemodynamics (heart rate (HR), preload and afterload) on LV mechanics during gestation. This was a cross-sectional study of 18 non-pregnant, 14 nulliparous pregnant (22-26 weeks' gestation) and 13 primiparous postpartum (12-16 weeks after delivery) women. All pregnant and postpartum women had uncomplicated, singleton gestations. Cardiac structure and function were assessed using echocardiography. LV mechanics, specifically longitudinal strain, circumferential strain and twist/untwist, were measured using speckle-tracking echocardiography. Differences between groups were identified using ANCOVA, with age, HR, end-diastolic volume (EDV) and systolic blood pressure (SBP) as covariates. Relationships between LV mechanics and hemodynamics were examined using Pearson's correlation. There were no significant differences in LV structure and traditional measurements of systolic and diastolic function between the three groups. Pregnant women, compared with non-pregnant ones, had significantly higher resting longitudinal strain (-22 ± 2% vs -17 ± 3%; P = 0.002) and basal circumferential strain (-23 ± 4% vs -16 ± 2%; P = 0.001). Apical circumferential strain and LV twist and untwist mechanics were similar between the three groups. No statistically significant relationships were observed between LV mechanics and HR, EDV or SBP within the groups. Compared to the non-pregnant state, pregnant women in the second trimester of a healthy pregnancy have significantly greater resting systolic function, as assessed by LV longitudinal and circumferential strain. Contrary to previous work, these data show that healthy pregnant women should not exhibit reductions in resting systolic function between 22 and 26 weeks' gestation. The enhanced myocardial contractile function during gestation does not appear to be related to hemodynamic load and could be the result of other physiological adaptations to pregnancy. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Left Ventricular Untwist During Isovolumic Relaxation Time in Patients with Diastolic Dysfunction

Left Ventricular Untwist During Isovolumic Relaxation Time in Patients with Diastolic Dysfunction

Recovery of Left Ventricular Twist and Left Ventricular Untwist Rate in Patients with ST-segment Elevation Acute Myocardial Infarction

Background: Left ventricular (LV) functional recovery and morphological remodeling after acute myocardial infarction (AMI) followed by reperfusion remain incompletely understood. The aim of the study was to describe the recovery of LV twist (LVT) and LV untwist rate (LVUR) upon revascularization after AMI using two-dimensional (2D) speckle tracking. Methods: We evaluated 88 subjects: 22 normal volunteers (mean age 31 ± 5 years), and 66 patients with AMI (mean age 65 ± 12 years), of which 40 had an inferior AMI and 26 an anterior one. All AMI patients had ST-segment elevation. Echocardiography was performed in all subjects. Patients were scanned within 36 h (baseline) after revascularization (percutaneous coronary intervention) and after 4 months (4 mFU). Apical and basal short-axis images were acquired (frame rate 67 ± 5 frames/s) and analyzed offline to extract the rotation (rate) curves. From these, maximal systolic LVT and peak LVUR were derived. Finally, the infarct size (IS) was estimated based on magnetic resonance imaging delayed enhancement and expressed as a percentage of the total LV volume. Results: At 36 h, LVT and LVUR were significantly reduced in both AMI groups when compared to normals. At 4 mFU, both AMI groups showed recovery in ejection fraction (EF) and reduction in IS (7.24 ± 10.07 vs. 20.13 ± 13.9, P &lt; 0.0001 for inferior AMI and 13.13 ± 10.3 vs. 24.40 ± 15, P &lt; 0.0001 for anterior AMI). LVT and LVUR increased significantly but remained below normal levels. Correlation of LVT and LVUR with IS was significant, but weak (r = 0.34 and r = 0.34, respectively). In addition, a fair correlation of LVT with EF (r = 0.64) and a weak correlation of LVUR with end-diastolic volume (r = 0.43) were found. Conclusion: LVT and LVUR are reduced in AMI patients early after reperfusion and recover incompletely upon follow-up. Interestingly, recovery of LVT characteristics as measured with this 2D speckle tracking-based method showed to be independent of infarct location or extent. LVT and LVUR might be good parameters to monitor the recovery of global LV function after treatment.

Left ventricular untwist in healthy children and adolescents born full-term

The aimof the study is to assess the left ventricle (LV) untwist in healthy children and adolescents born fullterm.Materials and methods.The analysis was carried out in 108 healthy children aged 2 months to 18 years, born full-term. LV untwist is assessed using Speckle Tracking Imaging at the basal and apical level.Results.Four types of LV untwist were identified in children and adolescents. We did not find relation between LV untwist and age, nor with LV index spherical in systole and diastole, LV myocardial mass. The relationship between LV untwisting and LV rotation in systole at basal and apical segments was revealed.Conclusion.The described features of LV loosening are apparently associated with processes of postnatal growth and maturation of heart tissues in children and adolescents.

Left ventricular untwist in patients with diastolic dysfunction: speckle tracking imaging study

Background There is no single noninvasive index that can directly assess diastolic function. Untwist contributes to diastolic suction and early filling. Speckle tracking imaging (STI) can be used to study the relation between diastolic indices and untwist in patients with diastolic dysfunction. Patients and methods A total of 75 patients with diastolic dysfunction and 25 normal volunteers were selected for this study. According to mitral flow pattern, the patients were classified into group I (abnormal relaxation), group II (pseudonormalized), and group III (stiffness pattern). Using STI, the basal and apical short-axis views were imaged. Stored data were processed to get apical and basal rotation, systolic twist, peak systolic twist ratio, diastolic untwist ratio, and time to peak twist and untwist ratio. Results Peak untwisting ratio was significantly higher in Group I Patients that decreased to be normalized and even decreased with progression of diastolic dysfunction from Group II to Group III. There was a highly significant positive and negative correlation with end-diastolic volume and end-systolic volume, respectively. Time to peak untwist ratio nonsignificantly increased from group I to III, with nonsignificant correlation between untwist ratio and peak E, A, and E/A ratio. Conclusion Patients with relaxation abnormality have a higher untwist ratio, which decreases gradually with progression from relaxation to stiffness pattern. It may appear as a compensatory mechanism to ensure early filling with relaxation abnormality.

Alterations in Cardiac Deformation, Timing of Contraction and Relaxation, and Early Myocardial Fibrosis Accompany the Apparent Recovery of Acute Stress-Induced (Takotsubo) Cardiomyopathy: An End to the Concept of Transience

Takotsubo syndrome is an increasingly recognized cause of chest pain and occasionally of cardiogenic shock. Despite rapid improvement of the left ventricular (LV) ejection fraction, recent registry data raise concerns about long-term prognosis. The aim of this study was to test the hypothesis that restoration of normal ejection fraction after acute takotsubo syndrome is not equivalent to full functional recovery. Fifty-two patients with takotsubo syndrome (according to the Mayo Clinic criteria plus cardiac magnetic resonance imaging to exclude myocardial infarction) and 44 healthy control subjects of the same age, gender, and cardiovascular comorbidity distribution were prospectively recruited. The focus of the investigation was on patients with takotsubo syndrome presenting with ST-segment elevation-type electrocardiographic findings or malignant arrhythmias and with LV apical ballooning variant, and a 4-month recovery endpoint was assessed. Patients underwent echocardiographic assessment of LV myocardial deformation (global longitudinal, radial, and circumferential strain; LV twist, torsion, and untwist; and time to peak twist and untwist) and assessment of LV myocardial structure by pre- and post-contrast-enhanced cardiac magnetic resonance by T1 mapping acutely and at 4-month follow-up. Control subjects underwent a single-time-point investigation. Data were analyzed using paired or unpaired tests, as appropriate for their distribution, and corrected for multiple comparisons. The patients' mean age was 66years (range, 28-87years), and 92% were women. All abnormal echocardiographic indices observed acutely in patients with takotsubo syndrome improved (but did not necessarily normalize) at follow-up. Significant mechanotemporal alterations characterizing both systole (global longitudinal strain and apical circumferential strain, P<.01 for both; LV twist, twist rate, and torsion, P<.0001 for all) and diastole (untwist rate and time to peak untwisting, P<.001 for both) persisted at 4-month follow-up compared with control subjects, despite normalization of LV ejection fraction and volumes. Although native T1 (which demonstrates edema) normalized at 4-months follow-up only in segments contracting normally during the acute phase (T1=1,180±40.6msec [normally contracting segments, P=.20 vs control value of 1,189±16msec] and T1=1,208±60.3msec [dysfunctional segments, P<.05 vs control]), the extracellular volume fraction (which demonstrates diffuse fibrosis) remained significantly abnormal in all LV segments (whether normally contracting [0.328±0.043, P<.001] or ballooning during acute presentation [0.320±0.044, P<.001], both vs control value of 0.273±0.045). In patients with the most clinically severe spectrum of takotsubo cardiomyopathy, regional LV systolic and diastolic deformation abnormalities persist beyond the acute event, despite normalization of global LV ejection fraction and size. In addition, although myocardial edema partly subsides, a process of global microscopic fibrosis develops in its place, detected as early as 4months.

Exercise Training Normalizes Timing of Left Ventricular Untwist Rate, but Not Peak Untwist Rate, in Individuals with Type 2 Diabetes and Diastolic Dysfunction: A Pilot Study

There is limited information regarding the role of left ventricular (LV) twist and the effect of exercise in type 2 diabetes (T2D). The aim of this study was to compare LV twist parameters in patients with T2D versus healthy control subjects and the effects of high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on LV twist in patients with T2D with diastolic dysfunction. This study, which included both prospective and retrospective components, included 47 patients with T2D and diastolic dysfunction and 37 healthy individuals. Patients with T2D were randomized to HIIE (4×4min at 90%-95% of maximal heart rate, three times a week, 120min/wk; n=24) or MIE (210min/wk; n=23) for 12weeks and examined with echocardiography (LV twist by speckle-tracking method) at baseline and posttest. The control subjects received no intervention and were matched according to age, gender, and body mass index to those completing the intervention. In total, 37 subjects completed 12weeks of MIE (n=17) or HIIE (n=20). LV peak untwist rate (UTR) was similar in patients with T2D and control subjects (P˃.05). At baseline, LV peak UTR, relative to total diastolic period, occurred 5.8 percentage points later in patients with T2D compared with control subjects (P=.004). Time to peak UTR was shortened by 6.5 percentage points (P=.002) and 7.7 percentage points (P<.001) after MIE and HIIE, respectively. Time to peak UTR was similar to that in control subjects after exercise interventions. In patients with T2D and diastolic dysfunction, LV peak UTR was similar, but time to peak LV UTR was delayed compared with control subjects. Twelve weeks of endurance exercise normalized the timing of UTR.

The impact of an experimentally induced increase in arterial blood pressure on left ventricular twist mechanics.

The effects of isometric hand-grip exercise (IHG) coupled with a period of postexercise circulatory occlusion (OCC; known to sustain exercise-induced increases in blood pressure while facilitating a decrease in heart rate) on left ventricular (LV) twist mechanics was examined. Two-dimensional speckle-tracking echocardiography was used to assess LV apical and basal rotation and LV twist in 19 healthy participants (23 ± 2 years old) at rest, during 3 min of IHG (performed at 40% maximal voluntary contraction) and 3 min of OCC immediately following IHG. The IHG elicited significant (P < 0.001) increases in mean arterial pressure (rest, 91 ± 1 mmHg; IHG, 122 ± 2 mmHg) and heart rate (rest, 65 ± 2 beats min(-1); IHG, 91 ± 4 beats min(-1)). Mean arterial pressure remained elevated during OCC (116 ± 2 mmHg; P < 0.001 versus rest), whereas heart rate returned to resting levels (68 ± 3 beats min(-1); P = 0.159 versus rest). Apical rotation decreased significantly (P < 0.01) by 10 ± 5% during IHG and 21 ± 4% during OCC, whereas basal rotation remained unchanged from rest. Left ventricular twist decreased from rest to IHG (12 ± 5%; P = 0.015) and OCC (21 ± 4%; P = 0.001), whereas a decrease in LV untwist rate was observed only during OCC. An increase in blood pressure generated by IHG, and maintained by a period of OCC, impairs aspects of LV twist mechanics. Postexercise circulatory occlusion isolated the effect of the arterial blood pressure rise (from heart rate), magnifying the impairment of LV twist mechanics when compared with IHG, whilst also negatively impacting LV relaxation. We propose that a protocol using isometric exercise followed by circulatory occlusion provides a method for studying the effects of blood pressure changes on LV twist mechanics.

Does the Intraventricular Pressure Gradient Increase following Acute High Intensity Interval Exercise in Heart Failure?

An increase in the diastolic intraventricular pressure gradient (IVPG) is an important mechanism that aids in left ventricular filling during exercise. Prior work has shown that individuals with severe heart failure have impairment in IVPG at peak exercise (Am J Physiol Heart Circ Physiol 2005; 289: H2081-H2088). We have previously shown in the present study cohort (J Appl Physiol 2011; 110: 398-406) that left ventricular peak twist reserve is blunted, but that left ventricular peak untwisting rate, due to an increase in peak basal rotation rate and not peak apical rotation rate, is enhanced following acute high intensity interval (HIT) exercise in patients with mild heart failure. It is unclear whether regional differences in rotational properties of the ventricle in heart failure (i.e., base versus apex) that we have observed affect the IVPG post-HIT. PURPOSE: To determine if the IVPG immediately following acute HIT would be increased despite impaired apical contribution to left ventricular untwisting. METHODS: Nine patients (49 ± 16 years; 6 male) with mild heart failure (NYHA Class I/II = 7/2; left ventricular ejection fraction = 36 ± 7%; peak VO2 = 27 ± 9 ml/kg/min) performed 1 session of HIT (4 × 4 min at 96 ± 10% peak heart rate with a 3 min recovery period between bouts). Cardiac MRI (1.5 T scanner) was performed at rest prior to HIT and 6 ± 2 min following HIT. Rotational mechanics and IVPG were analyzed using in-house techniques with custom software. Analyses were performed using 2-tailed paired t-testing with p<0.05 being significant. RESULTS: Our novel finding is that the IVPG from pre-HIT (1.8 ± 1.0 mmHg) to post-HIT (1.6 ± 0.7 mmHg) remained effectively unchanged (p>0.05), despite a significant 24% increase in untwisting rate (p<0.05) that was modulated primarily by an increase in peak basal and not peak apical rotation rate. CONCLUSION: The maintenance of, but not the increase in, IVPG may aid in diastolic filling following HIT in patients with mild heart failure. Impairment in apical rotational mechanics likely account for the poor IVPG reserve of the left ventricle in mild heart failure.

Left Ventricular Rotational Mechanics in Preterm Infants Less Than 29 Weeks’ Gestation over the First Week after Birth

There is a paucity of data on left ventricular (LV) rotational physiology, twist, and torsional mechanics in preterm infants. The principal aims of the present study were to assess the feasibility and reproducibility of measuring LV rotation, twist, and torsion in preterm infants (<29 weeks' gestation) using two-dimensional speckle-tracking echocardiography and to examine the changes in those parameters over the first week after birth. This was a prospective observational study involving preterm infants <29 weeks' gestation. Echocardiographic evaluations were performed on days 1, 2, and 5 to 7 after delivery. LV basal and apical rotation, LV twist, LV twist rate (LVTR), and LV untwist rate (LVUTR) were measured from the basal and apical short-axis parasternal views and calculated using two-dimensional speckle-tracking echocardiography. Torsion was also calculated by normalizing LV twist to LV end-diastolic length. One-way repeated-measures analysis of variance was used to compare values across the three time points. Intra- and interobserver reproducibility were assessed using Bland-Altman analysis and the intraclass correlation coefficient. Fifty-one infants with a mean ± SD gestational age of 26.8 ± 1.5 weeks and a mean birth weight of 945 ± 233 g were included. There was high intra- and interobserver reproducibility for basal and apical rotation, LV twist, and LV torsion, with intraclass correlation coefficients ranging from 0.78 to 0.96 (P < .001 for all). Intra- and interobserver intraclass correlation coefficients for LVTR and LVUTR ranged from 0.70 to 0.88 (P < .001 for all). Apical rotation remained constant over the first week of age in a positive counterclockwise fashion (11.8 ± 5.0° vs 12.1 ± 6.1° vs 11.7 ± 8.3°, P = .92). Basal rotation changed from counterclockwise on day 1 to clockwise on day 7 (median, 5.5° [interquartile range, -0.3° to 8.3°] vs 4.0 [interquartile range, -4.7° to 7.2°] vs -4.5° [interquartile range, -5.8° to -2.3°], P < .001), with resultant net increases in twist and torsion (P < .05). There was no change in LVTR (P = .60), but LVUTR increased across the same time period (P = .01). Assessment of twist, LVTR, and LVUTR is feasible in preterm infants, with acceptable reproducibility. There are increases in LV twist and torsion in addition to LVUTR, suggesting changes in LV mechanics during the first week of age.

Left Ventricular Torsional Parameters in Patients With Non-Ischemic Dilated Cardiomyopathy

Background: Velocity vector imaging (VVI) is a new echocardiography method to assess myocardial deformation in two dimensions. Objectives: In this study, we used VVI to evaluate left ventricular (LV) main torsional parameters in non-ischemic dilated cardiomyopathy (DCM) patients in compared with normal subjects. Patients and Methods: Twenty-six DCM patients and Twenty-four normal subjects were assessed. Echocardiographic images of the short axis apical and basal views of LV were processed by VVI software to measure peak rotation degrees and also peak rotation rates in systole. LV twist was well-defined as the net difference between apical and basal rotation values and also LV torsion was considered as LV twist divided by left ventricular diastolic longitudinal length. In addition, peak untwisting value and untwisting rate were measured in diastole too. Results: LV twist value (5.54 ± 1.94° in DCM VS. 11.5 ± 2.45° in control group) and also LV torsion (0.71 ± 0.28°/cm in DCM VS. 1.53 ± 0.42°/cm in control group) were significantly decreased in DCM patients compared with normal group (P < 0.001 for both); also, the twisting rate was notably lower in DCM vs. control (38.68 ± 14.43°/s in DCM vs. 75.88 ± 17.25°/s in control; P < 0.001) and also untwisting rate (36.28 ± 13.48°/s in DCM vs. -73.79 ± 24.45°/s in control; P < 0.001), However normalization of these times for systolic duration or LV length creates different values. Conclusions: LV twist, torsion and untwist and also rate of them are significantly impaired in DCM and this impairment is well-related to LV global systolic and diastolic dysfunction. VVI is a new noninvasive technique that can be used to evaluate LV torsional parameters.

Left Ventricular Rotational Mechanics before and after Exercise in Children

In children, there is limited information regarding the relative contribution of left ventricular (LV) apical and basal rotation to increase LV pump function with exercise. The aim of this study was to test the hypothesis that a progressive increase in LV pump function with exercise is related to increased LV apical and basal rotation. Forty-two subjects 12 to 18 years of age with normal cardiac structure and function were recruited prospectively and imaged at rest, and in 20 subjects, imaging was repeated after moderate exercise. Conventional measures of LV systolic and diastolic performance were evaluated. Left ventricular rotation, LV twist, rotational rate, and recoil and untwist rates were measured using two-dimensional speckle-tracking echocardiography. Torsion was calculated by normalizing LV twist to LV diastolic length. Twist displacement loops were constructed from data obtained at rest and after exercise. Apical rotation increased significantly after exercise (7.33 ± 2.8° vs 11.6 ± 4.7°, P = .0004), but basal rotation did not (-4.85 ± 1.9 vs -6.46 ± 4.81, P = .21). Similarly, peak twist, torsion, and twist rate also increased significantly after exercise. In diastole, apical recoil rate and LV untwist rate also increased significantly with exercise. The slope of the systolic limb of the twist displacement loop and the area enclosed by the loop also increased significantly with exercise. Increases in global LV pump function during exercise in children are associated with enhanced LV apical rotation but not LV basal rotation. In addition, unique changes were seen in twist displacement loops in children before and after exercise. These data may serve as a foundation for understanding future applications of LV rotational mechanics in disease states.