Assessment of Left Ventricular Myocardial Viability by 3-Dimensional Speckle-Tracking Echocardiography in Patients With Myocardial Infarction

Diagnostic accuracy of segmental strain analysis by cardiac magnetic resonance feature tracking for chronic myocardial ischemic scar assessment

RATIONALE AND OBJECTIVE

This study investigates the potential of segmental strain parameters derived from cine magnetic resonance imaging (MRI) using feature tracking (FT) to detect chronic ischemic scars in patients with ischemic heart disease, offering an alternative to late gadolinium enhancement (LGE) MRI, which has limitations such as long scan times and contraindications to gadolinium.

PATIENTS AND METHODS

A total of 47 patients with chronic coronary syndrome and 20 healthy controls were enrolled, with CMR examinations performed on a 1.5 Tesla MRI system. Strain parameters were analyzed from 1072 myocardial segments. Myocardial segments were categorized into four groups: healthy controls, remote myocardium (no late gadolinium enhancement), scarred-viable (<50 % scar transmurality), and nonviable (>50 % scar transmurality).

RESULTS

Results showed significant differences in segmental peak circumferential strain (SPCS), peak radial strain (SPRS), and peak longitudinal strain (SPLS) between scarred viable and nonviable segments compared to remote and control segments, with all p-values <0.001. Specifically, SPCS had a superior ability to distinguish scarred myocardium from remote tissue, showing an area under the curve (AUC) of 0.77, with a sensitivity of 71.5 % and specificity of 70 %. For differentiating nonviable from viable myocardium, SPCS achieved an AUC of 0.80, with a sensitivity of 82.02 % and specificity of 70.21 %.

CONCLUSION

CMR-FT strain analysis is promising complementary tool, particularly in situations where contrast administration is contraindicated or when a rapid, non-contrast assessment of myocardial viability and potential scar burden is desired.

Left Ventricular Function in Patients on Maintenance Hemodialysis: A Three-Dimensional Speckle-Tracking Imaging Study

INTRODUCTION

Although maintenance hemodialysis (MHD) in end-stage renal disease (ESRD) appears to induce some risk factors and strengthen cardiac function, the morbidity of ESRD patients receiving hemodialysis remains high. This study aimed to identify left ventricular (LV) structural and functional abnormalities in ESRD patients on MHD using three-dimensional speckle-tracking imaging (3D-STI).

METHODS

Eighty-five ESRD patients with normal LV ejection fraction (LVEF >50%) participated in this study, including 55 MHD patients comprising the chronic kidney disease (CKD) V-D group and 30 nondialysis patients comprising the CKD V-ND group. Thirty age- and sex-matched control participants who had normal kidney function were enrolled as the N group. Conventional echocardiography and 3D-STI were conducted, and global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS), and global radial strain (GRS) values were measured.

RESULTS

No substantial differences in two-dimensional LVEF were observed among the three groups, and LV hypertrophy was the most common abnormality in patients with ESRD, irrespective of whether they had received or not received MHD. There were no significant differences in the 3D LV mass index between the CKD V-ND and N groups (p > 0.05). Conversely, the 3D LV mass index was considerably higher in the CKD V-D group than in both the N and CKD V-ND groups. The GLS, GAS, and GRS values were significantly lower in the CKD V-ND group than in the N group (p < 0.05). Furthermore, the CKD V-D group had significantly lower GLS, GCS, GAS, and GRS values than the N and CKD V-ND groups (p < 0.05). The interventricular septal thickness and E/e' ratio were independently associated with LV strain values in all patients with ESRD.

CONCLUSIONS

MHD can exacerbate LV deformation and dysfunction in ESRD patients with preserved LVEF, and 3D-STI can be potentially useful for detecting these asymptomatic preclinical abnormalities.

Prediction of prognosis in patients with left ventricular dysfunction using three-dimensional strain echocardiography and cardiac magnetic resonance imaging

BACKGROUND

We evaluated three-dimensional speckle tracking echocardiography (3DSTE) strain and cardiac magnetic resonance (CMR) with delayed contrast enhancement (DCE) for the prediction of cardiac events in left ventricular (LV) dysfunction.

METHODS

CMR and 3DSTE in 75 patients with ischaemic and 38 with non-ischaemic LV dysfunction were analysed and temporally correlated to cardiac events during 41 ± 9 months of follow-up.

RESULTS

Cardiac events occurred in 44 patients, more in patients with ischaemic LV dysfunction. LV ejection fraction (LVEF), global circumferential and global area strain were reduced more in patients with more cardiac events, whereas 3DSTE LV end-systolic volumes and 3DSTE LV masses were larger. However, the area under the curve using receiver-operating characteristic analysis showed modest sensitivity and specificity for all evaluated parameters. Additionally, DCE did not differ significantly between the two groups. Univariate analysis showed ischaemic aetiology of LV dysfunction, LVEF and LV mass by CMR to be predictors of cardiac events with an increased relative risk of 2.4, 1.6 and 1.5, respectively. By multivariate analysis, only myocardial ischaemia and LVEF ≤ 39% were independent predictors of events (p = 0.004 and 0.005, respectively). Subgroup analysis in ischaemic and non-ischaemic patients showed only 3DSTE LV mass in ischaemic patients to have a significant association (p = 0.033) but without an increased relative risk.

CONCLUSION

LVEF calculated by 3DSTE or CMR were both good predictors of cardiac events in patients with LV dysfunction. A reduced LVEF ≤ 39% was associated with a 1.6-fold higher probability of a cardiac event. 3DSTE strain measurements and DCE-CMR did not add to the prognostic value of LVEF.

Hierarchical Template Matching for 3D Myocardial Tracking and Cardiac Strain Estimation

Myocardial tracking and strain estimation can non-invasively assess cardiac functioning using subject-specific MRI. As the left-ventricle does not have a uniform shape and functioning from base to apex, the development of 3D MRI has provided opportunities for simultaneous 3D tracking, and 3D strain estimation. We have extended a Local Weighted Mean (LWM) transformation function for 3D, and incorporated in a Hierarchical Template Matching model to solve 3D myocardial tracking and strain estimation problem. The LWM does not need to solve a large system of equations, provides smooth displacement of myocardial points, and adapt local geometric differences in images. Hence, 3D myocardial tracking can be performed with 1.49 mm median error, and without large error outliers. The maximum error of tracking is up to 24% reduced compared to benchmark methods. Moreover, the estimated strain can be insightful to improve 3D imaging protocols, and the computer code of LWM could also be useful for geo-spatial and manufacturing image analysis researchers.

Left ventricular hypertrophy as protective factor after bypass grafting

Left ventricular hypertrophy (LVH) is a well established cardiovascular risk factor, accounting for an increase in cardiovascular morbid-mortality, although how much the magnitude and the kind of LVH could affect cardiovascular outcomes is in large part unknown. We speculate that mild LVH in absence of left ventricular (LV) chamber dilation, could play a protective role towards functional capacity, clinical outcome, cardiovascular and total morbi-mortality in conditions in which LV systolic function is generally reduced. Accordingly to many epidemiological observations, the availability of extra-quote of systolic function could lead to a significative improvement in the final outcome of some kinds of heart patients, as those undergoing bypass-grafting, where the stress for heart and cardiovascular system is always high. We suppose that the functional reserve available for patients with LVH could make the difference with respect to other patients undergoing myocardial revascularization. Similarly, the availability of a contractile reserve warranted by LVH could ensure a little gain in the outcome for patients after other major cardiovascular events (such as myocardial infarction or other heart surgery as surgical valve replacement). However, our hypothesis only involves mild LVH without LV chamber dilation, that is the initial stage of "non-dilated concentric" LVH and "non-dilated eccentric" LVH according to the new four-tiered classification of LVH based on relative wall thickness and LV dilation. Support for our hypothesis derives from the well-known protective role of systolic function that is a major factor in almost all cardiovascular diseases, where LV ejection fraction (LVEF) has shown to significantly improve quality of life, as well as morbidity and mortality. The knowledge that mild LVH in absence of LV chamber dilation is not as harmful in such conditions as believed at present could make avoidable some drugs prescription in some stages of the disease. Furthermore, it may allow a better evaluation of the risk profile of patients with LVH undergoing some cardiovascular major events like bypass grafting, myocardial infarction or surgical heart valve replacement.

Three-dimensional speckle-tracking echocardiography: benefits and limitations of integrating myocardial mechanics with three-dimensional imaging

Three-dimensional (3D) speckle-tracking echocardiography (3DSTE) is an advanced imaging technique designed for left ventricular (LV) myocardial deformation analysis based on 3D data sets. 3DSTE has the potential to overcome some of the intrinsic limitations of two-dimensional STE (2DSTE) in the assessment of complex LV myocardial mechanics, offering additional deformation parameters (such as area strain) and a comprehensive quantitation of LV geometry and function from a single 3D acquisition. Albeit being a relatively young technique still undergoing technological developments, several experimental studies and clinical investigations have already demonstrated the reliability and feasibility of 3DSTE, as well as several advantages of 3DSTE over 2DSTE. This technique has provided new insights into LV mechanics in several clinical fields, such as the objective assessment of global and regional LV function in ischemic and non-ischemic heart diseases, the evaluation of LV mechanical dyssynchrony, as well as the detection of subclinical cardiac dysfunction in cardiovascular conditions at risk of progression to overt heart failure. However, 3DSTE generally requires patient's breathhold and regular rhythm for enabling an ECG-gated multi-beat 3D acquisition. In addition, the measurements, normal limits and cut-off values pertaining to 3D strain parameters are currently vendor-specific and highly dependent on the 3D ultrasound equipment used. Technological advances with improvement in spatial and temporal resolution and a standardized methodology for obtaining vendor-independent 3D strain measurements are expected in the future for a widespread application of 3DSTE in both clinical and research arenas. The purpose of this review is to summarize currently available data on 3DSTE methodology (feasibility, accuracy and reproducibility), strengths and weaknesses with respect to 2DSTE, as well as the main clinical applications and future research priorities of this emerging technology.

Homeostatic Left Heart integration and disintegration links atrio-ventricular covariation's dyshomeostasis in Hypertrophic Cardiomyopathy

Left ventricle and left atrium are and have been practically always analyzed separately in common clinically and non-clinically oriented cardiovascular investigations. Both classic and speckle tracking echocardiographic data contributed to the knowledge about deformational impairments occurring in systo-diastolic differences. Recently new trajectory based approaches allowed a greater awareness about the entire left ventricle or left atrium revolution and on their deficiencies that take place in presence of hypertrophic cardiomyopathy. However, surprisingly, the concomitant function of the two left heart chambers has not been analyzed for their geometrical/mechanical relationship. For the first time we study here, by acquiring left ventricle and left atrial geometries on the same heartbeat, the trajectory attributes of the entire left heart treated as a whole shape and the shape covariation of its two subunits. We contrasted healthy subjects with patients affected by hypertrophic cardiomyopathy. We found impaired left heart trajectory mainly in terms of orientation and size. More importantly, we found profound differences in the direction of morphological covariation of left ventricle and left atrium. These findings open to new perspectives in pathophysiological evaluation of different diseases by allowing the appreciation of concomitant functioning of both left heart whole geometry and of its two chambers.