Left ventricular remodeling in twin pregnancy, noninvasively assessed using hemodynamic forces and pressure-volume relation analysis: prospective, cohort study.

This study was designed to prospectively investigate the pattern of intraventricular hemodynamic forces (HDFs) associated with left ventricular (LV) function and remodeling in women with uncomplicated twin pregnancy. Transthoracic echocardiography was performed on 35 women (aged 35.9 ± 4.7-yr old) during gestation (T1, <14 wk; T2, 14-27 wk; T3, >28 wk) and 6-7 mo after delivery (T0). LV HDFs were computed from echocardiography long-axis data sets using a novel technique based on endocardial boundary tracking, both in apex-base (A-B) and latero-septal (L-S) directions. HDF distribution was evaluated by L-S over A-B HDF ratio (L-S:A-B HDF ratio). At T1, L-S:A-B HDF ratio was higher than in T0 (P < 0.05) indicating HDF misalignment. At T2, a slight impairment of cardiac function was then recorded with a reduction of global longitudinal strain (GLS) and left ventricular end-systolic elastance (Ees) at pressure-volume relationship analysis versus T1 (both P < 0.05). Finally, at T3, when HDF misalignment and LV contractility reduction (GLS and Ees) were all restored, a rightward shift of the end-diastolic pressure-volume relationship (EDPVR) with an increase of ventricular capacitance was documented. In twin pregnancy, HDF misalignment in the first trimester precedes the slight temporary decrease in left ventricular systolic function in the second trimester; at the third trimester, a rightward shift of the EDPVR was associated with a realignment of HDF and normalization of ventricular contractility indexes. These coordinated changes that occur in the maternal heart during twin pregnancy suggest the role of HDFs in cardiac remodeling.NEW & NOTEWORTHY These changes indicate that 1) the misalignment of hemodynamic forces (HDFs) precedes a mild reduction in systolic function in twin pregnancy and 2) the positive left ventricular (LV) response to hemodynamic stress is mainly due to an improved diastolic function with enhanced LV cavity compliance.

Impact of left ventricular hemodynamic forces in adult patients with treated aortic coarctation and preserved left ventricular systolic function.

BACKGROUND: The LV myocardial strain and hemodynamic forces (HDFs) are innovative markers of LV function. Aortic coarctation is safely repaired in infancy; however, mortality and morbidity remain increased in later life. The study investigated the role of left ventricular myocardial deformation and HDFs in asymptomatic patients who underwent successful aortic coarctation repair. METHODS: Clinical and echocardiographic data were analyzed from 42 repaired CoA, 32 ± 20 years after surgery, 2D echocardiographic global longitudinal strain (GLS), circumferential strain (GCS) and HDFs were determined. CoA patients were compared with 42 patients affected by blood hypertension and 84 healthy controls; all matched for age and gender. RESULTS: All groups had normal LV ejection fraction (LVEF), dimensions, and volumes. CoA patients showed a significantly higher rate of LV mass indexed (p < .001) and left atrial volumes indexed (p < .001). LV myocardial and endocardial global longitudinal and circumferential strain were decreased in CoA patients (p < .001, p < .001; p = .032 and p < .001, respectively). HDF parameters such as LV longitudinal force, LV systolic longitudinal force and LV impulse (LVim) were uniformly reduced (p = .006, p = .001, and p = .001, respectively). LV myocardial strain and HDF parameter values were independently associated with hospitalization for heart failure on univariable Cox regression analysis. CONCLUSION: Despite preserved LVEF, patients with CoA had lower LV myocardial strain and HDF parameters values, independently associated with hospitalization for heart failure.

Difference in cardiac remodeling between female athletes and pregnant women: a case control study.

OBJECTIVES: The aim of this study was to detect possible differences in reversible cardiac remodeling occurring in sport training and twin pregnancy. BACKGROUND: cardiac remodeling occurs in athletes and pregnant women due to training and fetal requirements, respectively. These changes could be apparently similar. METHODS: 21 female elite athletes (23.2 ± 5.3 years), 25 women with twin pregnancies (35.4 ± 5.7 years) and 25 healthy competitive female athletes (controls), age-matched with pregnant women (34.9 ± 7.9 years), were enrolled. This latter group was included to minimize the effect of age on cardiac remodeling. All women evaluated through anamnestic collection, physical examination, 12 leads ECG, standard echocardiogram and strain analysis. Sphericity (SI) and apical conicity (ACI) indexes were also calculated. RESULTS: Pregnant women showed higher LA dimension (p < 0.001) compared to both groups of athletes. LV e RV GLS were significantly different in pregnant women compared to female athletes (p = 0.02 and 0.03, respectively). RV GLS was also different between pregnant women and controls (p = 0.02). Pregnant women showed significantly higher S' wave compared to female athletes (p = 0.02) but not controls. Parameters of diastolic function were significantly higher in athletes (p = 0.08 for IVRT and p < 0.001 for E/A,). SI was lower in athletes in both diastole (p = 0.01) and systole (p < 0.001), while ACIs was lower in pregnant women (p = 0.04). CONCLUSIONS: Cardiac remodeling of athletes and pregnant women could be similar at first sight but different in LV shape and in GLS, highlighting a profound difference in longitudinal deformation between athletes and pregnant women. This difference seems not to be related with age. These findings suggest that an initial maternal cardiovascular maladaptation could occur in the third trimester of twin pregnancies.

Simultaneous Volumetric and Functional Assessment of the Right Ventricle in Hypoplastic Left Heart Syndrome After Fontan Palliation, Utilizing 3-Dimensional Speckle-Tracking Echocardiography.

BACKGROUND: Right ventricular (RV) volumetric and functional assessments are both crucial for the management of patients with hypoplastic left heart syndrome (HLHS). 3-dimensional echocardiography (3DE) for volume measurements and 2D speckle-tracking echocardiography (2D-STE) for strain analysis are performed separately. 3D-STE is capable of evaluating those parameters simultaneously and providing principal strain (PS), unifying the concepts of myofiber orientation and contraction into a single, maximal contractile direction. However, the application of 3D-STE to HLHS has not been studied and so became the aim of our study.Methods and Results:64 HLHS patients after Fontan palliation underwent 3D-STE analysis measuring RV end-diastolic volume index (EDVi), ejection fraction (EF), global PS (GPS), global circumferential strain (GCS), and global longitudinal strain (GLS). Volume measurements were compared between 3D-STE and 3DE, and strains were compared between 3D- and 2D-STE. EDVi and EF showed strong correlations between 3D-STE and 3DE (r=0.93 and 0.87, respectively). GCS and GLS showed moderate correlations between 3D- and 2D-STE (r=0.65 and 0.61, respectively). GPS showed highest magnitude and excellent correlation with EF (r=-0.95). CONCLUSIONS: Simultaneous volumetric and functional assessment by 3D-STE was a useful method in this HLHS cohort. PS is a promising parameter for evaluating the RV function of HLHS, which could be useful during longitudinal follow-up.

Intracardiac flow analysis in cardiac resynchronization therapy: A new challenge?

In the past years, assessment of cardiac function has become possible through the analysis of intracardiac flow dynamics, performed noninvasively using phase-contrast cardiac magnetic resonance and contrast and noncontrast ultrasound techniques. From 2013 to 2019, 9 echocardiographic investigations have considered 215 patients with cardiac resynchronization therapy (CRT) as a model for assessing flow dynamics within the left ventricle. Preliminary results have been reported about the acute hemodynamic effects of CRT and programming of the CRT device, showing the potential of an approach based on analysis of intracardiac flows. At present, there are only scarce data on the capability of intracardiac flow dynamics to predict LV remodeling after CRT and no information on clinical outcome prediction. Future investigations should be aimed at clarifying the mechanisms and impact of maladaptive intracardiac vortex dynamics on progressive LV remodeling as well as the prognostic meaning of implanted CRT device based on cardiac flow analysis.

Hemodynamic forces using four-dimensional flow MRI: an independent biomarker of cardiac function in heart failure with left ventricular dyssynchrony?

Patients with heart failure with left ventricular (LV) dyssynchrony often do not respond to cardiac resynchronization therapy (CRT), indicating that the pathophysiology is insufficiently understood. Intracardiac hemodynamic forces computed from four-dimensional (4-D) flow MRI have been proposed as a new measure of cardiac function. We therefore aimed to investigate how hemodynamic forces are altered in LV dyssynchrony. Thirty-one patients with heart failure and LV dyssynchrony and 39 control subjects underwent cardiac MRI with the acquisition of 4-D flow. Hemodynamic forces were computed using Navier-Stokes equations and integrated over the manually delineated LV volume. The ratio between transverse (lateral-septal and inferior-anterior) and longitudinal (apical-basal) forces was calculated for systole and diastole separately and compared with QRS duration, aortic valve opening delay, global longitudinal strain, and ejection fraction (EF). Patients exhibited hemodynamic force patterns that were significantly altered compared with control subjects, including loss of longitudinal forces in diastole (force ratio, control subjects vs. patients: 0.32 vs. 0.90, P < 0.0001) and increased transverse force magnitudes. The systolic force ratio was correlated with global longitudinal strain and EF ( P < 0.01). The diastolic force ratio separated patients from control subjects (area under the curve: 0.98, P < 0.0001) but was not correlated to other dyssynchrony measures ( P > 0.05 for all). Hemodynamic forces by 4-D flow represent a new approach to the quantification of LV dyssynchrony. Diastolic force patterns separate healthy from diseased ventricles. Different force patterns in patients indicate the possible use of force analysis for risk stratification and CRT implantation guidance. NEW & NOTEWORTHY In this report, we demonstrate that patients with heart failure with left ventricular dyssynchrony exhibit significantly altered hemodynamic forces compared with normal. Force patterns in patients mechanistically reflect left ventricular dysfunction on the organ level, largely independent of traditional dyssynchrony measures. Force analysis may help clinical decision making and could potentially be used to improve therapy outcomes.

Cardiac fluid dynamics meets deformation imaging.

Cardiac function is about creating and sustaining blood in motion. This is achieved through a proper sequence of myocardial deformation whose final goal is that of creating flow. Deformation imaging provided valuable contributions to understanding cardiac mechanics; more recently, several studies evidenced the existence of an intimate relationship between cardiac function and intra-ventricular fluid dynamics. This paper summarizes the recent advances in cardiac flow evaluations, highlighting its relationship with heart wall mechanics assessed through the newest techniques of deformation imaging and finally providing an opinion of the most promising clinical perspectives of this emerging field. It will be shown how fluid dynamics can integrate volumetric and deformation assessments to provide a further level of knowledge of cardiac mechanics.

Left and right ventricular hemodynamic forces in healthy volunteers and elite athletes assessed with 4D flow magnetic resonance imaging.

Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only left ventricular (LV) forces. Right ventricular (RV) forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify 3D hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. Twenty five controls, 14 elite endurance athletes, and 2 patients with LV dyssynchrony were included. 4D flow data were used as input for the Navier-Stokes equations to compute hemodynamic forces over the entire cardiac cycle. Hemodynamic forces were found in a qualitatively consistent pattern in all healthy subjects, with variations in amplitude. LV forces were mainly aligned along the apical-basal longitudinal axis, with an additional component aimed toward the aortic valve during systole. Conversely, RV forces were found in both longitudinal and short-axis planes, with a systolic force component driving a slingshot-like acceleration that explains the mechanism behind the redirection of blood flow toward the pulmonary valve. No differences were found between controls and athletes when indexing forces to ventricular volumes, indicating that cardiac force expenditures are tuned to accelerate blood similarly in small and large hearts. Patients' forces differed from controls in both timing and amplitude. Normal cardiac pumping is associated with specific force patterns for both ventricles, and deviation from these forces may be a sensitive marker of ventricular dysfunction. Reference values are provided for future studies.NEW & NOTEWORTHY Biventricular hemodynamic forces were quantified for the first time in healthy controls and elite athletes (n = 39). Hemodynamic forces constitute a slingshot-like mechanism in the right ventricle, redirecting blood flow toward the pulmonary circulation. Force patterns were similar between healthy subjects and athletes, indicating potential utility as a cardiac function biomarker.

Cardiac resynchronization therapy by multipoint pacing improves response of left ventricular mechanics and fluid dynamics: a three-dimensional and particle image velocimetry echo study.

AIMS: To characterize the effect of multipoint pacing (MPP) compared to biventricular pacing (BiV) on left ventricle (LV) mechanics and intraventricular fluid dynamics by three-dimensional echocardiography (3DE) and echocardiographic particle imaging velocimetry (Echo-PIV). METHODS AND RESULTS: In 11 consecutive patients [8 men; median age 65 years (57-75)] receiving cardiac resynchronization therapy (CRT) with a quadripolar LV lead (Quartet,St.Jude Medical,Inc.), 3DE and Echo-PIV data were collected for each pacing configuration (CRT-OFF, BiV, and MPP) at follow-up after 6 months. 3DE data included LV volumes, LV ejection fraction (LVEF), strain, and systolic dyssynchrony index (SDI). Echo-PIV was used to evaluate the directional distribution of global blood flow momentum, ranging from zero, when flow force is predominantly along the base-apex direction, up to 90° when it becomes transversal. MPP resulted in significant reduction in end-diastolic and end-systolic volumes compared with both CRT-OFF (P = 0.02; P = 0.008, respectively) and BiV (P = 0.04; P = 0.03, respectively). LVEF and cardiac output were significant superior in MPP compared with CRT-OFF, but similar between MPP and BiV. Statistical significant differences when comparing global longitudinal and circumferential strain and SDI with MPP vs. CRT-OFF were observed (P = 0.008; P = 0.008; P = 0.01, respectively). There was also a trend towards improvement in strain between BiV and MPP that did not reach statistical significance. MPP reflected into a significant reduction of the deviation of global blood flow momentum compared with both CRT-OFF and BiV (P = 0.002) indicating a systematic increase of longitudinal alignment from the base-apex orientation of the haemodynamic forces. CONCLUSION: These preliminary results suggest that MPP resulted in significant improvement of LV mechanics and fluid dynamics compared with BiV. However, larger studies are needed to confirm this hypothesis.

Principles of cardiovascular magnetic resonance feature tracking and echocardiographic speckle tracking for informed clinical use.

Tissue tracking technology of routinely acquired cardiovascular magnetic resonance (CMR) cine acquisitions has increased the apparent ease and availability of non-invasive assessments of myocardial deformation in clinical research and practice. Its widespread availability thanks to the fact that this technology can in principle be applied on images that are part of every CMR or echocardiographic protocol. However, the two modalities are based on very different methods of image acquisition and reconstruction, each with their respective strengths and limitations. The image tracking methods applied are not necessarily directly comparable between the modalities, or with those based on dedicated CMR acquisitions for strain measurement such as tagging or displacement encoding. Here we describe the principles underlying the image tracking methods for CMR and echocardiography, and the translation of the resulting tracking estimates into parameters suited to describe myocardial mechanics. Technical limitations are presented with the objective of suggesting potential solutions that may allow informed and appropriate use in clinical applications.

3D Strain helps relating LV function to LV and structure in athletes.

INTRODUCTION: The evaluation of cardiac contraction could benefit from a connection with the underlying helical structure of cardiac fibers in athletes either completely healthy or with minor common cardiopathies like Bicuspid Aortic Valve (BAV). This study aims to exploit the potential role of 3D strain to improve the physiological understanding of LV function and modification due to physical activity as a comparative model. METHODS: Three age-matched groups of young (age 20.3 ± 5.4) individuals are prospectively enrolled: 15 normal healthy subjects, 15 healthy athletes, and 20 athletes with bicuspid aortic valve (BAV). All subjects underwent echocardiographic examination and both 2D and 3D strain analysis. RESULTS: All echo parameters were within the normal range in the three groups. Global values of end-systolic longitudinal and circumferential strain, assesses by either 2D or 3D analysis, were not significantly different. The 3D strain analysis was extended in terms of principal and secondary strain (PS, SS). Global PS was very similar, global SS was significantly higher in athletes and displays a modified time course. The comparative analysis of strain-lines pattern suggests that the enhancement of LV function is achieved by a more synchronous recruitment of both left- and right-handed helical fibers. CONCLUSIONS: 3D strain analysis allows a deeper physiological understanding of LV contraction in different types of athletes. Secondary strain, only available in 3D, identifies increase of performances due to physical activity; this appears to follow from the synergic activation of endocardial and epicardial fibers.

Comparative analysis of left ventricle function and deformation imaging in short and long axis plane in cardiac magnetic resonance imaging.

Background: Advancements in cardiac imaging have revolutionized our understanding of ventricular contraction. While ejection fraction (EF) is still the gold standard parameter to assess left ventricle (LV) function, strain imaging (SI) has provided valuable insights into ventricular mechanics. The lack of an integrative method including SI parameters in a single, validated formula may limit its use. Our aim was to compare different methods for evaluating global circumferential strain (GCS) and their relationship with global longitudinal strain (GLS) and EF in CMR and how the different evaluations fit in the theoretical relationship between EF and global strain. Methods: Retrospective monocenter study. Inclusion of every patient who underwent a CMR during a 15 months period with various clinical indication (congenital heart defect, myocarditis, cardiomyopathy). A minimum of three LV long-axis planes and a stack of short-axis slices covering the LV using classical steady-state free precession cine sequences. A single assessment of GLS on long axis (LAX) slices and a double assessment of GCS and EF with both short axis (SAX) and LAX slices were made by a single experienced CMR investigator. Results: GCS-SAX and GCS-LAX were correlated (r = 0.77, P < 0.001) without being interchangeable with a high reproducibility for GCS, GLS and EF. EF calculated from LAX images showed an overestimation compared to EF derived from SAX images of 7%. The correlation between calculated EF and theoretical EF derived from SI was high (r = 0.88 with EF-SAX, 0.95 with EF-LAX). Data conclusion: This study highlights the need to integrate strain imaging techniques into clinical by incorporating strain parameters into EF calculations, because it gives a deeper understanding of cardiac mechanics.

Association between echocardiography-derived haemodynamic force parameters and left ventricular reverse remodelling after cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) may induce left ventricular (LV) reverse remodelling (=LV response) in patients with heart failure. Intraventricular pressure gradients can be quantified using echocardiography-derived haemodynamic forces (HDF). The aim was to evaluate the association between baseline HDF and LV response and to compare the change of HDF after CRT between LV responders and LV non-responders. METHODS AND RESULTS: The following HDF parameters were assessed: 1)apical-basal (AB) strength, 2)lateral-septal strength, 3)force vector angle, 4)systolic AB impulse, 5)systolic force vector angle. LV response was defined as a reduction of LV end-systolic volume ≥15% at six months. One hundred ninety-six patients were included (64±11 years, 122(62%) men), 136(69%) showed LV response. On multivariable logistic regression analysis, the force vector angle in the complete heart cycle (OR 1.083 (95%CI 1.018, 1.153), p=0.012) and the systolic force vector angle (OR 1.089 (95%CI 1.021, 1.161), p=0.009), both included in separate models, were independently associated with LV response. Six months after CRT, LV responders had greater AB strength, AB impulse and higher force vector angles, while LV non-responders only showed improvement in the force vector angle in the complete heart cycle. CONCLUSION: The orientation of HDF at baseline is associated with LV response to CRT. Six months after CRT, the orientation of HDF improves in LV responders and LV non-responders, while the magnitude of AB HDF only improves in LV responders.

Haemodynamic Forces: Emerging Markers of Ventricular Remodelling in Multiple Myeloma Cardiovascular Baseline Risk Assessment.

Multiple myeloma (MM) affects a population with a high prevalence of cardiovascular (CV) disease. These patients benefit from an accurate CV risk evaluation in order to choose the safest drug regimen. Haemodynamic forces (HDFs) analysis allows for the earlier detection of myocardial damage compared with standard markers; the role played by MM in HDFs alteration, with or without the influence of hypertension, is yet to be studied. Therefore, we aimed to identify differences in HDFs analysis in patients with MM, hypertension or both versus normotensive non-oncologic subjects. A total of 173 patients (MM hypertensive patients, MMHT; MM normotensive patients, MMNT; non-oncologic hypertensive patients, CoHT; and non-oncologic normotensive patients, CoNT) underwent transthoracic echocardiography for HDFs analysis and pulse wave velocity (PWV) assessment. Hypertensive patients (MMHT, CoHT) showed decreased ejection fraction (EF), global longitudinal strain (GLS) and HDFs values compared with CoNT, whereas ventricular mass (LVMi) and PWV increased. MMNT displayed a significant reduction in systolic HDFs (p < 0.006) and systolic ejection HDFs (p < 0.008) compared with CoNT, without significant change in EF, GLS, LVMi or PWV. In conclusion, MM leads to ventricular remodelling regardless of hypertension; HDFs application for MM patients could help detect early myocardial damage, especially in patients receiving cardiotoxic drugs.

Changes of intracardiac flow dynamics measured by HyperDoppler in patients with aortic stenosis.

Aims: Assessment of intracardiac flow dynamics has recently acquired significance due to the development of new measurement methods based on echocardiography. Recent studies have demonstrated that cardiac abnormalities are associated with changes in intracardiac vortical flows. Yet, no previous study assessed the impact of aortic stenosis (AS) on intracardiac vortices. This study aims to explore the clinical potential of additional information provided by quantifying intracardiac flow dynamics in patients with AS. Methods and results: One hundred and twenty patients with severe AS, sixty patients with concentric ventricular remodelling (VR), and hundred controls (CTRL) were prospectively included and underwent non-invasive evaluation of intracardiac flow dynamics. In addition to standard echocardiography, fluid dynamics were assessed by means of HyperDoppler. Vortex depth (P < 0.001), vortex length (P = 0.003), vortex intensity (P < 0.001), and vortex area (P = 0.049) were significantly increased in AS compared with CTRL. In addition, mean energy dissipation was significantly higher in AS compared with CTRL (P < 0.001) and VR (P = 0.002). At receiver operating characteristic analysis, vortex depth showed the best discrimination capacity for AS (P < 0.001). Conclusion: Changes in fluid dynamics-based HyperDoppler indices can be reliably assessed in patients with AS. Significant changes in vortex depth and intensity can selectively differentiate AS from both concentric remodelling and healthy CTRLs, suggesting that the assessment of intracardiac flow dynamics may provide complementary information to standard echocardiography to better characterize patients' subsets.

Assessing cardiac mechanics through left ventricular haemodynamic forces.

Haemodynamic forces (HDFs), which represent the forces exchanged between blood and surrounding tissues, are critical in regulating the structure and function of the left ventricle (LV). These forces can be assessed on cardiac magnetic resonance or transthoracic echocardiography exams using specialized software, offering a non-invasive alternative for measuring intraventricular pressure gradients. The analysis of HDFs can be a valuable tool in improving our understanding of cardiovascular disease and providing insights beyond traditional diagnostic and therapeutic approaches. For instance, HDF analysis has the potential to identify early signs of adverse remodelling and cardiac dysfunction, which may not be detected by standard imaging methods such as bidimensional or speckle-tracking echocardiography. This review aims to summarize the principles of HDF analysis and to reappraise its possible applications to cardiac disorders.

Myocardial stretch in early systole is a key determinant of the synchrony of left ventricular mechanical activity in vivo.

BACKGROUND: Recent in-vitro observations suggest that left ventricular (LV) contraction is powered by 'stretch activation', an intrinsic mechanism by which the stretching of an activated cardiomyocyte causes delayed force redevelopment. We hypothesized that mechanical dyssynchrony is related to prolonged early systolic stretch that delays the timing of peak segmental shortening. METHODS AND RESULTS: The time intervals from R wave to segmental longitudinal stretch in early systole (Tstretch) and peak shortening (Tpeak) and the respective standard deviations (σTstretch and σTpeak) were measured by speckle-tracking echocardiography in 57 patients undergoing cardiac resynchronization therapy (CRT). The percentage of time spent in shortening, normalized to Tpeak duration [corrected ΔT=(Tpeak-Tstretch)/Tpeak] correlated with LV reverse remodeling (reduction in end-systolic volume ≥ 15%). Of the 57 patients, 40 (70.2%) demonstrated LV reverse remodeling at an average follow-up of 263 ± 125 days after CRT. At baseline, Tstretch and σTstretch correlated with Tpeak and σTpeak, respectively. Though there was no difference in Tstretch, Tpeak, σTstretch and σTpeak between responders and non-responders, corrected ΔT in the mid-lateral and mid-septal segments was shorter in the responders (P<0.05 for both) and the average of the 2 independently predicted LV reverse remodeling (area under the curve: 0.77, P=0.001). CONCLUSIONS: Mapping LV segmental shortening in relation to early systolic stretch may aid dyssynchrony assessment in patients undergoing CRT.

Aging does not affect radial viscoelastic behavior of the left ventricle.

OBJECTIVES: This study investigates the effect of aging on the radial viscoelastic behavior of the left ventricle (LV) based on a previously validated model that uses myocardial tissue phase mapping (TPM) of cine phase-contrast MRI. METHODS: Previous studies suggest that aging remarkably influences regional myocardial motion, mostly myocardial velocities in both radial and long-axis directions. However, the effect of aging on cardiac viscoelasticity, which exhibits time-dependent strain, has not been elucidated yet. In this study, myocardial velocity and displacement mapping of the LV was performed using TPM in 39 healthy subjects divided into three age groups. The viscoelasticity parameters were obtained for each segment of the LV and compared among the studied groups. RESULTS: The analyses showed that myocardial elasticity ranged from approximately 20 to -20 dyne/cm2 during a cardiac cycle, and the myocardial viscous-damping component ranged from -1 to 1 dyne × s/cm2. Overall, no statistically significant difference was observed in the viscoelasticity components among the subjects in the different age groups (p > 0.05). CONCLUSION: Myocardial viscoelastic behavior of the LV in radial direction was found to be considerably similar in pattern and magnitude among the studied subjects of different age groups with no statistically significant difference, despite the fact that the regional myocardial velocities change due to aging.

Echocardiography and cardiac magnetic resonance-based feature tracking in the assessment of myocardial mechanics in tetralogy of Fallot: an intermodality comparison.

We investigated intermodality agreements of strains from two-dimensional echocardiography (2DE) and cardiac magnetic resonance (CMR) feature tracking (FT) in the assessment of right (RV) and left ventricular (LV) mechanics in tetralogy of Fallot (TOF). Patients were prospectively studied with 2DE and CMR performed contiguously. LV and RV strains were computed separately using 2DE and CMR-FT. Segmental and global longitudinal strains (GLS) for the LV and RV were measured from four-chamber views; LV radial (global radial strain [GRS]) and circumferential strains (GCS) measured from short-axis views. Intermodality and interobserver agreements were examined. In 40 patients (20 TOF, mean age 23 years and 20 adult controls), LV, GCS showed narrowest intermodality limits of agreement (mean percentage error 9.5%), followed by GLS (16.4%). RV GLS had mean intermodality difference of 25.7%. GLS and GCS had acceptable interobserver agreement for the LV and RV with both 2DE and CMR-FT, whereas GRS had high interobserver and intermodality variability. In conclusion, myocardial strains for the RV and LV derived using currently available 2DE and CMR-FT software are subject to considerable intermodality variability. For both modalities, LV GCS, LV GLS, and RV GLS are reproducible enough to warrant further investigation of incremental clinical merit.

Effect of Aging on Intraventricular Kinetic Energy and Energy Dissipation.

In recent years, analysis of kinetic energy (KE) and the rate of kinetic energy dissipation (KED) or energy loss (EL) within the cardiac chambers, obtained by cardiac imaging techniques, has gained increasing attention. Thus, there is a need to clarify the effect of physiological variables, specifically aging, on these energetic measures. To elucidate this aspect, we reviewed the literature on this topic. Overall, cardiac magnetic resonance and echocardiographic studies published so far indicate that aging affects the energetics of left and right intraventricular blood flow, although not all energy measures during the cardiac cycle seem to be affected by age in the same way. Current studies, however, have limitations. Additional large, multicenter investigations are needed to test the effect of physiological variables on intraventricular KE and KED/EL measures.