Left Ventricular Untwist Research Articles

QRS duration in left bundle branch block does not affect left ventricular twisting in chronic systolic heart failure.

Left ventricular (LV) torsion is an important parameter of LV performance and can be influenced by several factors. Aim of this investigation was to evaluate whether QRS prolongation in left bundle branch block (LBBB) may influence global LV twist and twisting/untwisting rate in chronic systolic heart failure (HF) patients. We prospectively evaluated 30 healthy subjects (control group) and 100 chronic HF patients with severely impaired LV systolic function (ejection fraction ≤ 35%). Patients were divided into three groups according to QRS duration: A: QRS < 120 ms (n 49), B: 120 ≤ QRS ≤ 150 ms (n 28) and C: QRS > 150 ms (n 23). Patients in groups B and C presented LBBB. All subjects underwent standard trans-thoracic echocardiography and two-dimensional speckle-tracking echocardiography evaluation. Categorical variables were compared by the chi-square or the Fisher's exact test. Continuous variables were compared using the ANOVA test. Correlations between variables were analysed with linear regression. Control subjects presented higher torsion parameters, when compared with patients in any HF group. Among the three HF groups, no differences were detected in global twist (4.79 ± 3.54, 3.8 ± 3.0 and 4.15 ± 3.14 degrees, respectively), twist rate max (44.81 ± 25.03, 37.94 ± 19.09 and 37.61 ± 24.49 degrees s(-1), respectively) and untwist rate max (-36.31 ± 30.89, -27.68 ± 34.67 and -39.62 ± 26.27 degrees s(-1), respectively) (P>0.05 for all). At linear regression analysis, there was no relation between QRS duration and any torsion parameter (P>0.05 for all). In patients with chronic severe systolic heart failure, QRS duration and LBBB morphology do not affect LV twisting and untwisting.

Effect of aliskiren on circulating endothelial progenitor cells and vascular function in patients with type 2 diabetes and essential hypertension.

The aim of this study was to investigate the effects of aliskiren on vascular function and endothelial progenitor cells (EPCs) in patients with type 2 diabetes and essential hypertension. The study enrolled type 2 diabetic patients aged >50 years under stable glycemic control and first diagnosed mild essential hypertension. In phase A (n = 20), patients received aliskiren 150-300 mg daily for 3 months. In phase B (n = 12), hydrochlorothiazide (HCTZ) 12.5-25mg daily substituted for aliskiren for 3 more months. At baseline and at the end of each phase, we assessed (i) brachial blood pressure (BBP); (ii) central aortic systolic pressure (CSP), aortic augmentation index (Aix), and pulse wave velocity (PWV) as markers of arterial stiffness; (iii) brachial artery flow-mediated dilatation (FMD) as a marker of endothelial function; (iv) left ventricular (LV) twisting and untwisting as markers of LV function and (v) EPC numbers in culture of peripheral blood mononuclear cells. Aliskiren similarly reduced BBP and CSP, increased FMD (P < 0.001) and EPC numbers (P < 0.001), decreased PWV and Aix (P < 0.05), and improved LV twisting and untwisting (P < 0.05). Although substitution of HCTZ sustained BBP at similar levels, CSP and echocardiographic indices nearly returned at baseline levels, and the improvement of FMD, PWV, Aix, and EPC numbers was abolished. Aliskiren had a favorable effect on endothelial function and EPCs, reduced arterial stiffness, and improved LV twisting and untwisting. These effects were independent of BBP lowering, as they were not observed after the achievement of similar values of BBP with HCTZ.

Left Ventricular and Atrial Functions in Hypertrophic Cardiomyopathy Patients with Very High LVOT Gradient: A Speckle Tracking Echocardiographic Study

Determination of myocardial deformation (strain) by two-dimensional (2D) speckle tracking echocardiography (STE) is a new method for evaluating left ventricular (LV) regional function in patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to assess LV and left atrial (LA) functions with 2DSTE in HCM patients and to investigate relation between strain analysis and LV outflow tract (LVOT) gradient. Forty consecutive HCM patients (26 male, mean age: 47.7 ± 15.2 years), and 40 healthy volunteers (22 male, mean age: 46.6 ± 11.2 years) were included in the study. All subjects underwent a transthoracic echocardiography for evaluation of LV and LA functions with 2DSTE. The HCM patients were divided into 2 groups according to the presence of resting LVOT gradient >100 mmHg. Left ventricular global longitudinal strain (GLS), global radial strain (GRS), and global circumferential strain (GCS) were significantly lower in patients with HCM compared with controls (-20.3 ± 3.6% vs. -24.1 ± 3.4% P < 0.001, 38.1 ± 12.8% vs. 44.8 ± 10.2% P = 0.012, and -22.0 ± 4.4% vs. -23.9 ± 4.0% P = 0.045, respectively). Although basal and apical rotation were similar between the groups, mid-rotation was significantly clockwise in HCM patients (-1.53 ± 2.06° vs. 0.05 ± 1.7° P < 0.001). Both LA reservoir functions and LA conduit functions were significantly lower in HCM patients (21.6 ± 9.1% vs. 39.4 ± 10.6% P < 0.001, and 10.5 ± 4.3% vs. 15.7 ± 5.3%, P < 0.001). Fifteen patients had a resting LVOT gradient of >100 mmHg and they had significantly decreased GLS, twist and untwist compared to the HCM patients with lower resting LVOT gradient (-18.7 ± 2.3% vs. -21.2 ± 3.9% P = 0.016, 19.4 ± 4.3° vs. 23.5 ± 7.4° P = 0.038 and -94.0 ± 29.1°/sec vs. -134.9 ± 55.8°/sec, 0.005, respectively). Although basal and apical rotation were similar between the 2 groups, mid-rotation was significantly clockwise in HCM patients with higher LVOT gradient (-2.52 ± 1.76° vs. -0.96 ± 2.03°, P = 0.018). Correlation analysis revealed that LVOT peak velocity was associated with GLS (r = -0.358, P = 0.023), LV mid-rotation (r = -0.366, P = 0.024), and LV untwist (r = -0.401, P = 0.013). Left ventricular and LA functions are impaired in patients with HCM. 2DSTE is useful in determining patients with impaired myocardial mechanics. High LVOT gradient may be one of the responsible factors that trigger deterioration of LV longitudinal strain and twist mechanics in patients with HCM. Further studies are required to clarify the preliminary results of this study.

Early changes in left ventricular diastolic function and left atrial function in chagas disease identified by tissue doppler and speckle tracking

Purpose: Up to 20 to 30% of chronic Chagas' disease patients are expected to develop the cardiac form of the disease. The identification of left ventricular (LV) diastolic dysfunction or left atrial (LA) dysfunction may yield a strategy to recognize early cardiac involvement. Our aim was to analyze these parameters in Chagas' disease patients with normal LV systolic function using new echocardiographic techniques. Methods: Echocardiograms from 52 Chagas' disease patients with the indeterminate form, 29 patients at the stage A of the cardiac form (changes limited to the electrocardiogram) and 25 controls were consecutively acquired. LV diastolic function was analyzed by interrogation of the mitral inflow, pulmonary vein flow, color M-mode flow propagation velocity, LV untwist and tissue Doppler of the mitral annulus. LA function was analyzed by real-time 3 dimensional echocardiography and LA strain (ɛ) analysis including global peak positive LA ɛ (ɛ pos peak), peak negative LA ɛ and total LA ɛ. Results: All groups presented similar age, gender distribution, chamber diameters, LV mass and LV systolic function. Diastolic dysfunction was more prevalent in stage A patients. While all controls presented normal LV diastolic function, 11.5% of the patients with the indeterminate form presented delayed relaxation and 2% pseudo-normal LV diastolic function and 35.5% of the patients at the stage A of the cardiac form presented delayed relaxation and 13.5% pseudo-normal LV diastolic function (p=0.0001). Tissue Doppler was the best index to discriminate the presence of diastolic dysfunction. E/E' ratio was progressively higher (C: 5.8±1.6; indeterminate: 7.0±1.7; stage A: 8.0±2.9; p=0.0008) and E'/A' ratio was progressively lower (C: 1.5±0.3; indeterminate: 1.2±0.5; stage A: 1.0±0.3; p=0.0004) from controls towards stage A patients. LA volumes were higher in stage A patients than in controls, but LA emptying fractions did not differ among the groups. LA ɛ pos peak was lower in stage A patients (15.1±4.2%) than in patients with the indeterminate form (17.9±4.8%) and controls (17.8±4.3%; p=0.02), while the other LA ɛ parameters did not differ among the groups. Conclusions: Patients with Chagas' disease and normal LV systolic function present LV diastolic dysfunction, which is more prevalent in patients at the stage A of the cardiac form. Tissue Doppler was the best index to discriminate the presence of diastolic dysfunction and routine evaluation of E'/A' ratio may enable its early recognition. Depression of LA conduit function in stage A patients was observed only by LA strain analysis.

Assessment of the Left Ventricular Untwisting in Patients With Acute Myocardial Infarction in Different Location by 2D Speckle Tracking Imaging

Left ventricular untwisting movement is considered as an important part of LV diastolic function. The location of myocardial infarction (MI) and number of MI segments may have different impact on left ventricular untwisting movement.

Assessment of Impact of Involved Coronary Artery Quantity on Left Ventricular Untwisting in Patients With CHD by 2DSTI

Diastolic function in patients with Coronary Heart Disease (CHD) may decrease. To assess LV Diastolic function in CHD patients with different involved coronary artery quantity by measuring the untwisting motion can provide basis for diagnosis for CHD.

Regional LV deformation in healthy individuals during isovolumetric contraction and ejection phases assessed by 2D speckle tracking echocardiography

The main purpose of the this human study was by speckle tracking imaging to characterize the regional and temporal distribution of normal left ventricular (LV) deformation and the LV geometry during isovolumetric contraction (IVC) and the ejection phase. Twelve healthy young men [22 (2·3) years] were included. Longitudinal and circumferential strain and local twist angle were measured at four LV short-axis levels: basal, papillary, subpapillary and apical level during IVC and ejection phases. In addition, LV length from apex to the atrio-ventricular level, two diameters at LV basal short-axis level and atrio-ventricular plane displacement (AVPD) were measured to characterize LV shape during IVC. During IVC, longitudinal and circumferential shortening was demonstrated at all four short-axis levels from base to apex, while the LV made a basal counterclockwise and apical clockwise rotation representing untwist. In addition, there was a reduction in LV length and changes in short-axis diameters at basal level and AVPD from end-diastole to end-IVC, reflecting that the LV changed from an oval to a more spherical shape. At end-systole, longitudinal and circumferential shortening and local twist angle were significantly increased towards apex (P<0·05). This study demonstrated that the IVC in healthy humans is characterized by regional longitudinal and circumferential shortening and LV untwist, which occurs parallel to geometric changes of the LV into a spherical shape. During ejection, increased regional gradients of LV deformation towards apex in LV longitudinal and circumferential shortening and local and net twist angle were demonstrated.

Left ventricular filling patterns and its relation to left ventricular untwist in patients with type 1 diabetes and normal ejection fraction

BackgroundWe evaluated young patients with type 1 diabetes (T1DM) who had normal left ventricular (LV) ejection fraction and used speckle tracking echocardiography to assess changes in LV untwisting. We used cardiac magnetic resonance imaging (MRI) to assess the LV filling patterns in these subjects. MethodsWe recruited 33 T1DM patients and 32 age-matched healthy controls (HC) into the study. Study participants underwent echocardiography, cardiac MRI and metabolic exercise testing. ResultsThe early peak LV untwisting rate (E) was similar in T1DM and HC (−11.9±4.6 0/cm/s vs −11.3±4.7 0/cm/s, P=0.29) but the late peak LV untwisting rate (A) was significantly increased in T1DM (−6.2±3 0/cm/s vs −4.9±3.9 0/cm/s, P<0.05). The time to early peak untwisting rate was not different (50.9±9.6% vs 48.4±7.3%, P=0.12) but the time to late peak untwisting rate was significantly delayed in T1DM patients (80.4±12.5% vs 72.7±14.6%, P<0.05). The LV filling patterns demonstrated a significantly increased left atrial (LA) contribution to LV filling in T1DM. On linear regression peak late filling rate (r=0.60, P<0.000), trans-mitral A wave (r=0.25, P<0.05) and A′ (r=0.30, P<0.01) were predictors of LA contribution to LV filling. ConclusionWe demonstrate for the first time using speckle tracking that LV untwisting rate E is preserved and untwisting rate A is increased and delayed in young patients with uncomplicated T1DM. The LA contribution to LV filling is increased in these patients and is directly related to increases in other indices of LA function like peak late filling rate, trans-mitral A wave and A′.

The Left Ventricle Responds to Acute Graded Elevation of Right Ventricular Afterload by Augmentation of Twist Magnitude and Untwist Rate

The right and left ventricles share the interventricular septum, which mechanically transmits pressure gradients. The aim of this study was to investigate how acute mild or moderate right ventricular (RV) afterload affects left ventricular (LV) function. In 14 open-chest pigs (mean weight, 43 ± 4 kg) with preserved pericardium, acute mild (>35 and ≤50 mm Hg) and moderate (>50 and ≤60 mm Hg) RV pressure loading conditions were induced by constriction of the pulmonary artery. Hemodynamic parameters and LV twist and untwist were evaluated under each condition. From baseline to mild and moderate RV afterload, the mean RV systolic pressure increased from 31.0 ± 4.3 to 41.1 ± 2.7 and 52.7 ± 3.4 mm Hg (P < .001), while LV twist magnitudes increased from 15.4 ± 5.1° to 18.5 ± 3.1° and 19.8 ± 5.0° (P= .004), respectively. Absolute values of LV untwist rate increased from -116.9 ± 64.9°/sec to -160.0 ± 53.3°/sec and -169.1 ± 47.0°/sec, respectively (P= .001). After adjusting for all variables, only the ratio of the early and atrial components of mitral inflow and RV outflow tract acceleration time was significantly associated with the LV twist magnitude and LV untwist rate. In an acute setting, the left ventricle responds to suddenly elevated RV afterload and decreased RV stroke volume by promptly increasing its twist magnitude and untwist rate.

Evaluation of left ventricular twist and untwist in patients with apical hypertrophic cardiomyopathy using velocity vector imaging

Objective To evaluate left ventricular(LV) twist and untwist using velocity vector imaging(VVI) in patients with apical hypertrophic cardiomyopathy (ApHCM). Methods Twenty-three patients diagnosed with ApHCM were consecutively enrolled and compared with normal controls. After a standard echocardiographic examination, parasternal basal and apical short-axis planes were scanned to quantify LV rotations,twist and LV untwist using VVI. Results Compared with the normal controls, the rotation and rotaional velocity of apical subendocardial myocardium were markedly decreased in ApHCM patients during the period of systole ( P＜0.05) ,but the decreases in basal planes were not significant. As a consequence,LV twist was significantly lower in ApHCM patients (P＜ 0.05). Compared to normal controls,the velocity of LV untwisting was also significantly decreased in ApHCM patients ( P＜0.05).Conclusions The twist and untwist of LV subendocardial myocardium were decreased in ApHCM patients.VVI is a useful method to assess the characteristics of LV twist and untwist in ApHCM patients. Key words: Echocardiography; Cardiomyopathy, hypertrophic; Ventricular function, left; Velocity vector imaging

Characteristics of left ventricular rotational mechanics in patients with systemic amyloidosis, systemic hypertension and normal left ventricular mass

Recently, two-dimensional (2D) speckle-tracking echocardiography has enabled assessment of a particular behaviour of left ventricular (LV) motion defined as twisting/untwisting. The aim of our study is to evaluate whether in early stage of hypertension and systemic amyloidosis, subclinical alteration of LV twist and untwist is already present even if no LV hypertrophy is evidenced. Forty-seven patients with light chain immunoglobulin amyloidosis (AL) entered the study and were classified having cardiac amyloidosis (CA) or not (NCA) if the mean value of LV wall thickness was ≥12 mm or not. Twenty-two consecutive patients with history of arterial essential hypertension (Hyp Group) and no sign of LV hypertrophy were enrolled. A total of 26 asymptomatic healthy subjects, age-matched, were analysed as control group. All three groups of patients and healthy subjects underwent traditional and 2D speckle-tracking echocardiography evaluation. LV diameters, volumes, wall thickness, mass, ejection fraction, E/A and E/E' ratio were evaluated. Twisting and untwisting rates were significantly increased in NCA and Hyp group when compared with CA and control group. Moreover, despite similar LV mass and diastolic dysfunction degree, untwisting rate peak was significantly delayed in NCA when compared with Hyp group. In patients with CA, untwisting rate delay was similar to patients with NCA. Our results show that amyloidosis and systemic hypertension produce both LV twist and untwist rate enhancement before LV hypertrophy is developed. In patients with amyloidosis irrespectively of LV infiltration degree, a significant LV untwisting rate peak delay occurs suggesting that different aetiology of cardiac involvement could differently affect LV untwisting rate.

Left ventricular rotation: a neglected aspect of the cardiac cycle

To describe the mechanics and possible clinical importance of left ventricular (LV) rotation, exemplify techniques to quantify LV rotation and illustrate the temporal relationship of cardiac pressures, electrocardiogram and LV rotation. Review of the literature combined with selected examples of echocardiographic measurements. Rotation of the left ventricle around its longitudinal axis is an important but thus far neglected aspect of the cardiac cycle. LV rotation during systole maximizes intracavitary pressures, increases stroke volume, and minimizes myocardial oxygen demand. Shearing and restoring forces accumulated during systolic twisting are released during early diastole and result in diastolic LV untwisting or recoil promoting early LV filling. LV twist and untwist are disturbed in a number of cardiac diseases and can be influenced by several therapeutic interventions by altering preload, afterload, contractility, heart rate, and/or sympathetic tone. The concept of LV twisting and untwisting closely linking LV systolic and diastolic function may carry potential diagnostic and therapeutic importance for the management of critically ill patients. Future clinical studies need to address the feasibility of assessing LV twist and untwist as well as the relevance of its therapeutic modulation in critically ill patients.

Evaluation of left ventricular torsion by two-dimensional ultrasound speckle tracking imaging in heart transplant patients

Objective To evaluate the value of left ventricular (LV) torsion for assessing left ventricular function in adult heart transplant patients using two-dimensional speckle tracking imaging.Methods Basal and apical LV short-axis view and apical LV long-axis view of two-demensional images were acquired in 30 heart transplant patients and 17 healthy volunteers. Using two-dimensional strain software,LV basal and apical rotation versus time profiles were obtained at their short-axis level respectively. LV torsion was defined as apical rotation relative to the base, so the LV torsion versus time profiles could be drawn. LV basal rotation,apical rotation,global torsion and their time to peak were respectively measured,and the rate of LV untwisting was calculated. Statistical analysis was used to find the difference between the two groups and to investigate the relationship between LV torsion or the rate of LV untwisting and echocardiographic parameters. Results LV apical rotation and LV global torsion in heart transplant group were significantly lower than those in normal group. LV global torsion inversely correlated with LV end systolic volume,positively with LV ejection fraction. There was no significant difference between the two groups in the rate of LV untwisting. The rate of LV untwisting didn't correlate with echocardiographic parameters. Conclusions LV torsion can be measured exactly by two-dimensional speckle tracking imaging, it can be used to quantify LV global systolic function in heart transplant patients. Key words: Echocardiography; Heart transplantation; Ventricular function,left; Torsion; Speckle tracking imaging

Left Ventricular Untwisting in Restrictive and Pseudorestrictive Left Ventricular Filling: Novel Insights into Diastology

Conceptually, an ideal therapeutic agent should target the underlying mechanisms that cause left ventricular (LV) diastolic dysfunction. The objective of our study was to gain further insight into the mechanics of diastology by comparison of LV untwisting measured by speckle tracking echocardiography (STE) in young healthy adults with normal and "pseudorestrictive" LV filling, and dilated cardiomyopathy (DCM) patients with "true restrictive" LV filling. The study comprised 20 healthy volunteers with a Doppler LV-inflow pattern compatible with restrictive LV filling but a diastolic early phase filling velocity/early diastolic velocity of the mitral annulus (E/Em) ratio <8 ("pseudorestrictive"), 20 for age and gender-matched healthy volunteers with normal LV filling and an E/Em ratio <8, and 10 DCM patients with "true restrictive" LV filling and an E/Em ratio >15. LV untwisting parameters were determined by STE. Compared to healthy subjects, DCM patients had decreased peak diastolic untwisting velocity (-62 +/- 33 degrees/s vs -113 +/- 25 degrees/s, P < 0.01) and untwisting rate (-15 +/- 9 degrees/s vs -51 +/- 24 degrees/s, P < 0.01). Compared to healthy subjects with normal LV filling, healthy subjects with "pseudorestrictive" LV filling had increased peak diastolic untwisting velocity (-123 +/- 25 degrees/s vs -104 +/- 30 degrees/s, P < 0.05) and untwisting rate (-59 +/- 23 degrees/s vs -44 +/- 22 degrees/s, P < 0.05). Faster LV untwisting plays a pivotal role in the rapid early diastolic filling occasionally seen in young healthy individuals. In contrast, in DCM patients untwisting is severely delayed and this impairment to utilize suction may reduce LV filling.

Diastolic Myocardial Mechanics in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterized by myocardial hypertrophy, fiber disarray, and fibrosis interfering with myocardial force generation and relaxation. Because conventional Doppler echocardiographic methods inadequately assess diastolic function in HCM, the aim of this study was to determine local and global left ventricular (LV) relaxation mechanics in patients with HCM. Seventy-two patients with HCM and 32 normal controls were studied. Using Velocity Vector Imaging, longitudinal and circumferential strain, strain rate, and rotation at the base, middle, and apex of the septal and lateral LV walls were measured. Differences between patients' functional class subgroups were assessed using analysis of variance, and Tukey's post hoc analysis was used to compare patients in HCM clinical subgroups with normal controls. Longitudinal strain and systolic and early diastolic strain rates were lower than normal in patients with HCM, whereas their circumferential values were higher. This suggests that shortening and relaxation orientation in HCM was more circumferential. The ratio of peak early diastolic to peak systolic strain rate decreased longitudinally and circumferentially in moderately to severely symptomatic (New York Heart Association class III or IV) patients (0.95 +/- 0.35 vs 0.89 +/- 0.35, P < .001). LV untwist was similarly prolonged in all HCM subgroups. LV relaxation assessed using the early apical reverse rotation fraction was significantly lower in patients with worse functional status (34 +/- 14% vs 18 +/- 4% in class I or II vs class III or IV). Left atrial volume increased, paralleling the severity of symptoms and the degree of diastolic dysfunction. The evaluation of biplane myocardial mechanics offers new insights into the evaluation of diastolic function and its relationship to clinical status.

Alterations in Left Ventricular Untwisting With Ageing

In order to gain further insight into age-associated changes of left ventricular (LV) diastolic function, the purpose of the current study was to investigate alterations in LV untwisting with ageing. The study comprised 75 healthy volunteers, classified into 3 groups: age 16-35 (n=25), 36-55 (n=25) and 56-75 (n=25) years. LV untwisting (as a percentage of peak systolic twist) at 5%, 10%, 15% and 50% of diastole, peak diastolic untwisting velocity, time-to-peak diastolic untwisting velocity and untwisting rate (mean untwisting velocity during the time interval from peak systolic twist to mitral valve opening) were assessed using speckle-tracking echocardiography. Untwisting at 5%, 10%, 15% and 50% of diastole decreased with ageing. Although the peak diastolic untwisting velocity and untwisting rate were not significantly different between the age groups, when normalized for LV peak systolic twist, these parameters decreased with advancing age (both P<0.01). Time-to-peak diastolic untwisting velocity increased with ageing (P<0.01). Impairment of the relative peak diastolic untwisting velocity and untwisting rate, resulting in delayed LV untwisting, may help to explain diastolic dysfunction in the elderly. (Circ J 2010; 74: 101 - 108).

Human Cardiac Stem Cells

The view of the heart as a static organ implies that myocyte death and formation play a negligible role in cardiac homeostasis. Although stem cells have been unexpectedly identified in several organs, including the brain, kidney, lung, and skeletal muscle, the search for a cardiac stem cell (CSC) has been perceived as a futile effort, given the acknowledged lack of regenerative potential of the myocardium. Nevertheless, in the past several years, the demonstration of myocyte renewal in the normal and diseased heart has revealed a new, dynamic, and lively picture of this organ. Components of the cell cycle machinery and markers of cell replication have been detected in cardiomyocytes. The demonstration that karyokinesis and cytokinesis involve cells expressing contractile proteins has provided evidence that cardiomyocyte division occurs in the adult heart.1 More recently, pulse-chase assays with thymidine analogs,2 lineage tracing protocols,3 and 14C birth dating of cells4 have shown the existence of myocyte turnover, a process that has been found to differ in magnitude according to the methods used for its documentation and quantification. Article see p 2559 Over the years, the heart has provided us with the evidence that solves the critical problem of the origin of cardiomyocytes. At this moment in time, paraphrasing Eugenio Montale, we could say that the human heart is “on the verge of betraying [its] final secret offering the opportunity to uncover…the still point of the world, the link that won't hold, the thread to untangle that will finally lead to the heart of a truth.”5 Newly generated myocytes may derive from division of preexisting parenchymal cells or from activation and differentiation of resident CSCs. Discriminating between these two possibilities is not an easy task. Fate-mapping strategies, which are commonly used to track the origin of cells and …

Left ventricular torsion and strain patterns in heart failure with normal ejection fraction are similar to age-related changes

We used speckle tracking echocardiography (STE) to make a comparison between the effects of ageing and of heart failure with normal ejection fraction (HfnEF) on left ventricular (LV) torsion and strain patterns. Forty patients with HfnEF, 27 young controls and 26 older controls, were prospectively recruited. All subjects underwent clinical examination, 12-lead electrocardiogram, pulmonary function test, echocardiogram, and metabolic exercise test. LV torsion increases with advancing age (older controls vs. young controls, 2.2 +/- 0.9 vs. 1.4 +/- 0.8 degrees /cm; P = 0.03). Circumferential strain was enhanced in patients with HfnEF (-24.7 +/- 4.7 vs. -20.0 +/- 4.9%; P = 0.003). Rotational deformation delay (time difference between peak basal rotation and peak apical rotation), global circumferential strain, E-velocity deceleration time, and LV end-diastolic volume index were independent predictors of LV torsion. LV torsion and body mass index were independent predictors of LV untwist rate. Ageing is associated with increased LV torsion secondary to reduced rotational deformation delay and increased peak basal rotation. LV torsion and strain patterns in patients with HfnEF are similar to age-related changes apart from circumferential strain, which is enhanced in patients with HfnEF.

Left Ventricular Untwisting Is an Important Determinant of Early Diastolic Function

We sought to establish the relationship between invasive measures of diastolic function and untwisting parameters measured with speckle tracking imaging. Left ventricular (LV) diastolic function is determined by early diastolic relaxation (which creates suction gradients for LV filling) and myocardial stiffness. Assessment of LV torsion has shown that untwisting begins before aortic valve closure and, in animals, might be an important component of normal diastolic filling. Studies in human subjects using indirect indexes derived from right heart catheterization have suggested a relationship between tau and measures of untwisting, but the relationship between directly measured diastolic function indexes with micromanometer catheters and untwisting parameters has not been established in human subjects. Simultaneous Millar micromanometer LV pressure and echocardiographic assessment was performed on 18 patients (10 male, mean age 66 years) with normal systolic function and a spectrum of diastolic function. Invasive rate of the rise of LV pressure, dp/dt minimum and tau were recorded as measures of active relaxation, and the LV minimum diastolic pressure was recorded as an index of diastolic suction. The LV stiffness constant and functional chamber stiffness were estimated from hybrid pressure-volume loops. Echocardiographic speckle tracking imaging was used to quantify torsion. As relaxation was impaired, (prolonged tau) untwisting was delayed (r = 0.35, p < 0.01). There were nonsignificant associations between reduced untwisting and longer values of tau and lower dp/dt minimum. Reduction in the extent of untwisting before mitral valve opening was associated with increased LV minimum diastolic pressure (r = -0.30, p < 0.034). No relation was observed between the LV stiffness constant (beta: r = 0.11, p = NS) or the functional LV chamber stiffness (b: r = 0.11, p = NS) and untwisting. Untwisting parameters are related to invasive indexes of LV relaxation and suction but not to LV stiffness. These data suggest that untwisting is an important component of early diastolic LV filling but not later diastolic events.

Left Ventricular Rotational Mechanics in Acute Myocardial Infarction and in Chronic (Ischemic and Nonischemic) Heart Failure Patients

Left ventricular (LV) twist and untwisting rate are emerging as global and thorough parameters for assessment of LV function. This study explored differences of LV twist and untwisting rate in patients with acute myocardial infarction (AMI) and patients with ischemic and nonischemic chronic heart failure (HF). Fifty patients with AMI, 49 with ischemic HF, and 38 with nonischemic HF were studied. As a control group, 28 subjects without evidence of structural heart disease were included. Speckle-tracking analysis was applied to LV short-axis images at basal and apical levels. LV twist was defined as the net difference of apical and basal rotations at isochronal time points. The first time derivative of LV untwist was defined as the LV untwisting rate. Compared with control subjects, peak LV twist was decreased in patients with AMI and extremely decreased in those with HF (p <0.001, analysis of variance). A strong correlation (r = 0.87, p <0.001) was found between peak LV twist and LV ejection fraction in the overall study population. LV untwisting rate was progressively decreased in patients with AMI and HF compared with control subjects (p <0.001, analysis of variance). A moderate correlation (r = 0.56, p <0.001) was noted between peak LV untwisting rate and grade of diastolic dysfunction in the overall study population. In conclusion, LV twist and untwisting rate are strongly related to LV systolic and diastolic functions, respectively. Impairment of LV function observed in patients with AMI and HF is associated with a decrease of LV twist and untwisting rate.