Physiologic Determinants of Left Ventricular Systolic Torsion Assessed by Speckle Tracking Echocardiography in Healthy Subjects

Speckle tracking echocardiography could detect the difference of pressure overload-induced myocardial remodelling between young and adult rats

The assessment by speckle tracking echocardiography (STE) provides useful information on regional and global left ventricular (LV) functions. The aim of the study is to investigate if STE-based strain analysis could detect the difference of pressure overload-induced myocardial remodelling between young and adult rats. Physiological, haemodynamic, histological measurements were performed post-operatively in young and adult rats with transverse aortic constriction (TAC) as well as the age-matched shams. Two-way ANOVA was used to detect the statistical difference of various measured parameters. Pressure overload decreased the ejection fraction, fractional shortening, dp/dt_max and |dp/dtmin|, but increased the LV end-diastolic (ED) pressure in adult rat hearts for nine weeks after TAC operation than those in young rat hearts. Pressure overload also resulted in different changes of peak strain and strain rate in the free wall, but similar changes in the interventricular septum of young and adult rat hearts. The changes in myocardial remodelling were confirmed by the histological analysis including the increased apoptosis rate of myocytes and collagen area ratio in the free wall of adult rat hearts of LV hypertrophy when compared with the young. Pressure overload alters myocardial components in different degrees between young and adult animals. STE-based strain analysis could detect the subtle difference of pressure overload-induced myocardial remodelling between young and adult rats.

Left Atrial Strain Predicts Pro-Thrombotic State in Patients with Non-Valvular Atrial Fibrillation

Background and Purpose

Atrial fibrillation (AF) has a high prevalence in the population and it is responsible for up to the 25% of the strokes in elderly people. The aim of our study was to assess the correlations of left atrial (LA) functional parameter, global peak atrial longitudinal strain (PALS), derived from speckle tracking echocardiography (STE), with transesophageal echocardiography (TEE) findings in patients with persistent AF undergoing TEE before electrical cardioversion or ablation procedures.

Methods

79 patients (58 males, 21 females) with persistent AF waiting for cardioversion were included in the study. The patients underwent conventional two-dimensional (2D) and 2D speckle tracking echocardiogram. PALS were measured in all subjects. Patients were divided into two groups according to the presence of reduced LA appendage (LAA) emptying velocity (<25 cm/s) and/or thrombus in the LAA at TEE examination.

Results

Patients with reduced LAA emptying velocity and/or thrombus at TEE examination showed a significantly higher LA volume and increased E/E' ratio. 4-chamber, 2-chamber and global PALS were significantly lower in patients with reduced LAA emptying velocity and/or thrombus (6.8 ± 2.0% vs. 27.5 ± 5.4%, P < 0.0001; 8.6 ± 3.5% vs. 29.4 ± 7.1%, P < 0.0001; 7.9 ± 3.2% vs. 28.5 ± 6.1%, P <0.0001, respectively). Among all variables analyzed, global PALS demonstrated the highest diagnostic accuracy (AUC of 0.92) and, with a cut-off value less than 8.1%, good sensitivity and specificity of 87% and 94%, respectively, to predict LAA thrombus and/or reduced LAA emptying velocity.

Longitudinal Strain Stress-Echo Evaluation of Aged Marginal Donor Hearts: Feasibility in the Adonhers Project

BACKGROUND

The Adonhers (aged donor heart rescue by stress-echo protocol) Project was created to resolve the current shortage of donor hearts. One of the great limits of stress echo is the operator dependency. Speckle-tracking echocardiography (STE), offering a quantitative objective analysis of myocardial deformation, may help to overcome this limit. This study aimed to verify feasibility of a stress-strain echo analysis in selection of aged donor hearts for heart transplant.

METHODS

From February 2014 to October 2015, 22 marginal candidate donors (16 men) ages 58 ± 4 years were initially enrolled. After legal declaration of brain death, all marginal donors underwent bedside echocardiography, with baseline and (when resting echocardiography was normal) dipyridamole (0.84 mg/kg in 6 minutes) stress echo. In all patients, left ventricular (LV) longitudinal myocardial deformation was obtained by STE in the 4-, 2-, and 3-chamber views, obtaining the average global longitudinal strain (GLS). GLS was assessed at baseline and at the peak of stress echo.

RESULTS

Baseline echocardiography showed wall motion abnormalities in 9 patients (excluded from donation). Stress echocardiography was performed in the remaining 13 patients. Results were normal in 8, who were uneventfully transplanted in marginal recipients. Stress results were abnormal in 5 (excluded from donation). STE was obtained in all cases (100% feasibility) and ΔGLS was significantly different between normal and pathological stress-echo (+13.2 ± 5.2 versus -6.1% ± 3.1%, P = .0001, respectively).

CONCLUSIONS

STE showed an excellent feasibility in analysis of LV myocardial longitudinal strain at baseline and at the peak of stress echo of marginal heart donors. Further experience is needed to confirm STE as a valuable additional mean to better interpret stress echo in marginal donors.

Speckle tracking analysis: a new tool for left atrial function analysis in systemic hypertension: an overview

Speckle tracking echocardiography (STE) is an imaging technique applied to the analysis of left atrial function. STE provides a non-Doppler, angle-independent and objective quantification of left atrial myocardial deformation. Data regarding feasibility, accuracy and clinical applications of left atrial strain are rapidly gathering. This review describes the fundamental concepts of left atrial STE, illustrates its pathophysiological background and discusses its emerging role in systemic arterial hypertension.

First Evidence of Cardiac Stem Cells From the Left Ventricular Apical Tip in Patients With Left Ventricular Assist Device Implantation

BACKGROUND

Recent studies have challenged the dogma that the adult heart is a postmitotic organ and raise the possibility of the existence of resident cardiac stem cells (CSCs). Our study aimed to explore if these CSCs are present in the "ventricular tip" obtained during left ventricular assist device (LVAD) implantation from patients with end-stage heart failure (HF) and the relationship with LV dysfunctional area extent.

METHODS

Four consecutive patients with ischemic cardiomyopathy and end-stage HF submitted to LVAD implantation were studied. The explanted "ventricular tip" was used as a sample of apical myocardial tissue for the pathological examination. Patients underwent clinical and echocardiographic examination, both standard transthoracic echocardiography (TTE) and speckle tracking echocardiography (STE), before LVAD implantation.

RESULTS

All patients presented severe apical dysfunction, with apical akinesis/diskinesis and very low levels of apical longitudinal strain (-3.5 ± 2.9%). Despite this, the presence of CSCs was demonstrated in pathological myocardial samples of "ventricular tip" in all 4 of the patients. It was found to be a mean of 6 c-kit cells in 10 fields magnification 40×.

CONCLUSIONS

Cardiac stem cells can be identified in the LV apical segment of patients who have undergone LVAD implantation despite LV apical fibrosis.

Left Ventricular Deformation and Myocardial Fibrosis in Patients With Advanced Heart Failure Requiring Transplantation

PURPOSE

To evaluate potential relationships between different components of left ventricular (LV) function and histopathological evidence for myocardial fibrosis in patients undergoing heart transplantation.

METHODS

The study population included patients with advanced heart failure, referred for an echocardiographic examination before heart transplantation. Traditional LV function measurements and global longitudinal strain (GLS) by speckle tracking echocardiography, averaging all LV segments in 4-, 2-, and 3-chamber views were obtained in all subjects. LV tissue samples were obtained from all patients who underwent heart transplantation. Myocardial fibrosis was assessed using Masson's staining.

RESULTS

Of 106 patients referred for cardiac transplantation, 47 underwent cardiac transplantation and were enrolled in the study. LV myocardial fibrosis and its grade strongly correlated with GLS (r = 0.75, P = .0001), modestly with global circumferential strain and LV torsion (r = 0.61, P = .001 and r = 0.52, P = .01, respectively) and weakly with mitral S' wave (r = -0.41; P = .01) and mitral annular plane systolic excursion (r = -0.35; P = .05) but did not correlate with LV ejection fraction (r = -0.12; P = NS). GLS had the strongest accuracy for detecting LV fibrosis (area under the curve, 0.92). None of the echo parameters correlated with patient's exercise capacity.

CONCLUSION

Global longitudinal strain is the most accurate LV global function measure that correlates with the extent of myocardial fibrosis in patients with advanced systolic HF requiring heart transplantation.

Left ventricular rotation and right-left ventricular interaction in congenital heart disease: the acute effects of interventional closure of patent arterial ducts and atrial septal defects

BACKGROUND

Left ventricular rotation is physiologically affected by acute changes in preload. We investigated the acute effect of preload changes in chronically underloaded and overloaded left ventricles in children with shunt lesions.

METHODS

A total of 15 patients with atrial septal defects (Group A: 7.4 ± 4.7 years, 11 females) and 14 patients with patent arterial ducts (Group B: 2.7 ± 3.1 years, 10 females) were investigated using 2D speckle-tracking echocardiography before and after interventional catheterisation. The rotational parameters of the patient group were compared with those of 29 matched healthy children (Group C).

RESULTS

Maximal torsion (A: 2.45 ± 0.9°/cm versus C: 1.8 ± 0.8°/cm, p < 0.05), apical peak systolic rotation (A: 12.6 ± 5.7° versus C: 8.7 ± 3.5°, p < 0.05), and the peak diastolic torsion rate (A: -147 ± 48°/second versus C: -110 ± 31°/second, p < 0.05) were elevated in Group A and dropped immediately to normal values after intervention (maximal torsion 1.5 ± 1.1°/cm, p < 0.05, apical peak systolic rotation 7.2 ± 4.1°, p < 0.05, and peak diastolic torsion rate -106 ± 35°/second, p < 0.05). Patients in Group B had decreased maximal torsion (B: 1.8 ± 1.1°/cm versus C: 3.8 ± 1.4°/cm, p < 0.05) and apical peak systolic rotation (B: 8.3 ± 6.1° versus C: 13.9 ± 4.3°, p < 0.05). Defect closure was followed by an increase in maximal torsion (B: 2.7 ± 1.4°/cm, p < 0.05) and the peak diastolic torsion rate (B: -133 ± 66°/second versus -176 ± 84°/second, p < 0.05).

CONCLUSIONS

Patients with chronically underloaded left ventricles compensate with an enhanced apical peak systolic rotation, maximal torsion, and quicker diastolic untwisting to facilitate diastolic filling. In patients with left ventricular dilatation by volume overload, the peak systolic apical rotation and the maximal torsion are decreased. After normalisation of the preload, they immediately return to normal and diastolic untwisting rebounds. These mechanisms are important for understanding the remodelling processes.

Relationship between pulse pressure variation and echocardiographic indices of left ventricular filling pressure in critically ill patients

BACKGROUND

Pulse pressure variation (PPV) is a dynamic index of fluid responsiveness. This parameter helps clinicians in improving haemodynamic status while avoiding potential fluid overload. Echocardiographic indices, such as E/E' ratio and left atrial (LA) strain by speckle tracking echocardiography (STE), are used to estimate left ventricular (LV) filling pressures. This study aimed at exploring the relationship between PPV and echocardiographic indices of LV filling pressures in critically ill patients.

METHODS

Twenty-two patients (mean age of 50.9 ± 21.6, male/female = 15/7) admitted to intensive care unit, and requiring mechanical ventilation and invasive arterial pressure monitoring, were studied. In all patients, two independent operators assessed simultaneously PPV, using a pulse contour method, mean E/E' ratio and peak atrial longitudinal strain (PALS) by means of STE. PALS values were obtained by averaging LA segments measured in the 4-chamber and 2-chamber views (global PALS).

RESULTS

A significant negative correlation was found between mean E/E' ratio and PPV (R(2) = -0.76; P<0.001). A positive correlation between global PALS and PPV was found (R(2) = 0.80, P<0.001). Mean global PALS of 26.2% demonstrated excellent accuracy (Area Under Roc Curve = 0.86, P<0.001), and good sensitivity (92%) and specificity (86%) in predicting a PPV >15%.

CONCLUSION

In a group of mechanically ventilated patients PPV, derived from pulse contour analysis, and echocardiographic preload parameters were well correlated. Global PALS by STE provided better estimation of PPV than mean E/E' ratio. PALS seems a potential alternative to PPV in assessing fluid responsiveness in critically ill patients.

Left ventricular torsion during exercise in patients with and without ischemic response to exercise echocardiography

INTRODUCTION AND OBJECTIVES

Left ventricular torsion decreases during transmural myocardial ischemia, but the effect of exercise on left ventricular torsion has not been widely studied. We hypothesized that exercise-induced ischemia may impair left ventricular torsion. Therefore, our aim was to study the effects of exercise on left ventricular torsion in patients with an ischemic response to exercise echocardiography and in patients with a normal response.

METHODS

A retrospective analysis was performed in 172 patients with ejection fraction ≥ 50% who were referred for exercise-echocardiography and studied by speckle imaging at rest, peak and postexercise. Torsion was defined as apical rotation - basal rotation (in degrees) / left ventricular length (in centimeters). A total of 114 patients had a normal exercise echocardiography and 58 patients had an ischemic response to exercise echocardiography.

RESULTS

Patients with ischemic response to the test exhibited less basal rotation at peak exercise (+0.30° [2.39°] vs -0.65° [2.61°] in the normal group; P = .03), whereas peak apical rotation was similar (ischemic response to the test, 7.80° [3.51°]; normal response, 7.27° [3.28°]; P =.36). Torsion at peak exercise was also similar (1.07° [0.60°] in the ischemic response to the test group vs 1.16° [0.57°] in normal group; P =.37). A more impaired peak basal rotation was found in patients with anterior or anterior+posterior involvement (anterior ischemic response, +1.22° [2.45°]; anterior + posterior ischemic response, -0.20° [2.25°]; posterior ischemic response, -0.71° [1.96°]; normal response, -0.65° [2.60°]; P =.02).

CONCLUSIONS

Basal rotation at peak exercise is impaired in patients with an ischemic response to exercise echocardiography, particularly in those with anterior involvement. Apical rotation and torsion are similar to those in patients with normal exercise echocardiography.

Comparison of right versus left ventricular strain analysis as a predictor of outcome in patients with systolic heart failure referred for heart transplantation

The aim of the present study was to explore the relation between right ventricular (RV) and left ventricular (LV) echocardiographic parameters with clinical outcome in patients with advanced heart failure referred for cardiac transplantation. Ninety-eight consecutive patients with advanced systolic heart failure, referred for cardiac transplant evaluation, were enrolled. All patients were prospectively followed for the development of new outcome events, which included hospitalization for acute heart failure, cardiovascular death, heart transplantation, intra-aortic balloon pump implantation, and ventricular assist device implantation. Conventional transthoracic echocardiography was performed in all subjects. RV longitudinal strain (RVLS) by speckle-tracking echocardiography was assessed by averaging all segments in apical 4-chamber view (global RVLS) and by averaging RV free-wall segments (free-wall RVLS). LV global longitudinal and global circumferential strains were also calculated. Of the 98 subjects at baseline, 46 had 67 new events during a mean follow-up of 1.5 ± 0.9 years. Free-wall RVLS, global RVLS, N-terminal fragment of the prohormone brain natriuretic peptide, RV fractional area change, and LV end-diastolic volume were independently predictive of combined outcomes (all p <0.0001). The overall performance for the prediction of cardiovascular events was greatest for free-wall RVLS (area under the curve free-wall RVLS: 0.87; global RVLS: 0.67; RV fractional area change: 0.60; N-terminal fragment of the prohormone brain natriuretic peptide, 0.62; global circumferential strain: 0.55; global longitudinal strain: 0.35; and LV ejection fraction: 0.26). Free-wall RVLS showed the highest adjusted hazards ratio. A graded association between the grade of RV dysfunction and the risk of cardiovascular events was only evident for free-wall RVLS and global RVLS. In conclusion, in patients referred for heart transplantation, RVLS is a stronger predictor of outcome than LV longitudinal strain and other conventional parameters, providing a stronger prognostic stratification.

Four-dimensional speckle tracking for assessing improvement in left ventricular contractility after coronary angioplasty

The objective of the study was to identify and quantify the potential improvement of left ventricular contractility after percutaneous transluminal coronary angioplasty (PTCA) using 4-dimensional (4D) speckle tracking echocardiography (4D STE). We investigated 41 patients with coronary disease by 4D STE pre- and 24 hours postcoronarography with (n = 18) or without (n = 23) PTCA. The 4D STE visualizes in real time the myocardium strain on 2- and 4-chamber apical views and on 3 transverse views of the left ventricle. Average and total strain of the left ventricle were measured. Of the 18 PTCA patients, 15 showed significant increase in left ventricle mean (+15 ± 6) and total strain (240 ± 100), which corresponded to an increase of 93% ± 55% from precoronarography, whereas the remainder showed no change. The total strain corresponded to 33% ± 10% (before PTCA) and 59% ± 11% (post PTCA) of the estimated normal strain for each patient. Strain improved in 70% of the segment downstream from the stent, and there was a negative correlation between the amplitude of the mean and total strain improvements after 24 hours and the mean and total strain values before PTCA. In the non-PTCA group, 21 of the 23 patients showed no changes in strain, whereas 2 showed improvement. The 4D STE showed significant improvements in left ventricular contractility in more than 70% of the areas downstream from the PTCA segment. This corresponded to an increase in the initial contractility by approximately 93% ± 55%; however, the myocardium contractility remained approximately 59% of normal level. No changes were seen in patients without PTCA.

Left ventricular twist in a normal African adult population

AIMS

Speckle tracking has emerged as a quantitative technique for assessing left ventricular (LV) function. However, no normative data for LV twist using speckle tracking echocardiography (STE) are available in the black population. This study assessed myocardial mechanics by determining LV twist parameters in different age groups using STE, and evaluated the effect of ageing on LV twist in this population.

METHODS AND RESULTS

The study population consisted of 127 healthy volunteers divided into four age groups: 20-29 (n = 34); 30-39 (n = 33); 40-49 (n = 29); and 50-65 (n = 31) years. Parasternal short-axis images of three consecutive end-expiratory cardiac cycles at LV basal, papillary muscle, and apical levels, and apical four-chamber images were obtained. Apical and (AR) basal (BR) LV peak systolic rotation during ejection and instantaneous LV peak systolic twist (net twist, defined as maximal value of instantaneous AR minus BR) were measured. Mean strain values were -17.28 ± 3.30% for longitudinal, -17.40 ± 3.29% for circumferential, and 57.49 ± 3.32% for radial strain. Mean rotational values were AR (5.56 ± 1.98°), BR (-3.31 ± 0.92°), and net twist (8.87 ± 2.21°). AR, BR, and net twist increased with age, whereas longitudinal, circumferential, and radial strain decreased with age. Multivariate linear regression analysis showed age as the main predictor of net twist (R(2) = 0.82, P < 0.0001).

CONCLUSION

These data establish values for strain and twist in a normal black adult population. Net twist increases with age, whereas strain parameters decrease. Age is the strongest independent predictor of LV twist.

Heart disease and left ventricular rotation - a systematic review and quantitative summary

Background

Left ventricular (LV) rotation is increasingly examined in those with heart disease. The available evidence measuring LV rotation in those with heart diseases has not been systematically reviewed.

Methods

To review systematically the evidence measuring LV rotational changes in various heart diseases compared to healthy controls, literature searches were conducted for appropriate articles using several electronic databases (e.g., MEDLINE, EMBASE). All randomized-controlled trials, prospective cohort and case–controlled studies that assessed LV rotation in relation to various heart conditions were included. Three independent reviewers evaluated each investigation’s quality using validated scales. Results were tabulated and levels of evidence assigned.

Results

A total of 1,782 studies were found through the systematic literature search. Upon review of the articles, 47 were included. The articles were separated into those investigating changes in LV rotation in participants with: aortic stenosis, myocardial infarction, hypertrophic cardiomyopathy, dilated cardiomyopathy, non-compaction, restrictive cardiomyopathy/ constrictive pericarditis, heart failure, diastolic dysfunction, heart transplant, implanted pacemaker, coronary artery disease and cardiovascular disease risk factors. Evidence showing changes in LV rotation due to various types of heart disease was supported by evidence with limited to moderate methodological quality.

Conclusions

Despite a relatively low quality and volume of evidence, the literature consistently shows that heart disease leads to marked changes in LV rotation, while rotational systolic-diastolic coupling is preserved. No prognostic information exists on the potential value of rotational measures of LV function. The literature suggests that measures of LV rotation may aid in diagnosing subclinical aortic stenosis and diastolic dysfunction.