Detection of abnormal myocardial deformation during acute myocardial ischemia using three-dimensional speckle tracking echocardiography

Myocardial motion in acute ischemia: revealing invisible deformation by echocardiography

Echocardiography has been used clinically to assess regional myocardial wall motion for the diagnosis of acute myocardial ischemia or stress-induced ischemia, but it is often difficult to distinguish hypokinetic motion from normal motion. Myocardial wall motion is affected by loading conditions as well as intrinsic contractility, making it challenging to define a normal range of wall motion. Therefore, hypokinesis is usually diagnosed by comparing target areas with other areas of myocardium considered normal (relative hypokinesis). Myocardial strain analysis by tissue Doppler echocardiography and speckle-tracking echocardiography has enabled objective and quantitative evaluation of regional myocardial wall motion. Peak systolic strain decreases during acute ischemia, but subtle and invisible myocardial motion, such as early systolic lengthening (ESL) and postsystolic shortening (PSS), also occurs, and the analysis of these subtle motions can improve the diagnostic accuracy of ischemia. However, the diagnosis of ischemic myocardium by strain analysis is not widely performed in clinical practice at this time due to several limitations. This article reviews the features of myocardial motion during acute ischemia, the mechanisms of ESL and PSS, the diagnosis of ischemic myocardium using strain analysis, and current approaches and future challenges to overcome the limitations in the detection of relative hypokinesis. This article also explains the use of ESL and PSS to detect myocardial ischemic memory that remains after brief ischemia.

Mechanistic study of electroacupuncture preconditioning in alleviating myocardial ischemia-reperfusion injury in rats: involvement of mTOR/ROS signaling pathway to inhibit ferroptosis

PURPOSE

The objective of this study was to investigate the mechanism of electroacupuncture pretreatment in reducing myocardial ischemia-reperfusion injury in rats.

MATERIALS AND METHODS

The comparison of HR among the different groups did not yield statistically significant differences (p > 0.05). Additionally, the trend of HR change at different time points within each group was not statistically significant (p > 0.05). In contrast, the comparison of SBP among the different groups showed statistically significant differences (p < 0.05). Furthermore, the trend of SBP change at different time points within each group exhibited significant differences (p < 0.05).

RESULTS

Compared to the Sham group, rats in the I/R group and EA control group showed a significant decrease in EF, FS, SOD, p-mTOR/mTOR, GPX4, and FTH1, and an increase in CK-MB, cTnI, LDH, iron, ROS, MDA, ACSL4, and NCOA4 (p < 0.05). Compared to EA control group, rats in the EA group exhibited a significant increase in EF, FS, SOD, p-mTOR/mTOR, GPX4, and FTH1, and a decrease in CK-MB, cTnI, LDH, iron, ROS, MDA, ACSL4, and NCOA4 (p < 0.05). Compared to the EA group, rats in the EA + RAP group showed a significant decrease in EF, FS, SOD, p-mTOR/mTOR, GPX4, and FTH1, and an increase in CK-MB, cTnI, LDH, iron, ROS, MDA, ACSL4, and NCOA4 (p < 0.05).

CONCLUSIONS

Electroacupuncture preconditioning confers protective effects against myocardial ischemia-reperfusion injury in rats. Its mechanism may involve the activation of the mTOR/ROS signaling pathway by electroacupuncture to inhibit ferroptosis.

Evaluation of Cardiac Function before and after PAD Regimen in Patients with Multiple Myeloma by Three-Dimensional Speckle Tracking Imaging

In this manuscript, we have evaluated numerous changes of cardiac function in patients with multiple myeloma before and after PAD chemotherapy with 3D speck tracking imaging (3D-STI). For this purpose, 39 patients with multiple myeloma, from July 2019 to December 2020, who received the PAD regimen (bortezomib + doxorubicin liposome + dexamethasone, a course of 12 days) were selected as subjects. A comparison of two-dimensional conventional echocardiographic parameters before and after chemotherapy and 3D-STI related parameters was carried out. After 6 cycles of chemotherapy, the levels of TAPSE, RVFAC, and LVEF were significantly lower than those before chemotherapy (P < 0.05). There was no significant difference in the results of left and right ventricle two-dimensional conventional echocardiography before chemotherapy and 2 or 4 cycles after chemotherapy (P > 0.05). There were significant differences in the levels of RVGCS, RVGLS, RVGRS, LVGLS, and LVGRS before and after chemotherapy (P < 0.05). Specifically, RVGCS: after 6 cycles of chemotherapy < after 4 cycles of chemotherapy < before chemotherapy; RVGLS: after 6 cycles of chemotherapy < after 4 cycles of chemotherapy < after 2 cycles of chemotherapy < before chemotherapy; RVGRS: after 6 cycles of chemotherapy < after 4 cycles of chemotherapy < before chemotherapy; LVGLS: after 6 cycles of chemotherapy < after 4 cycles of chemotherapy < before chemotherapy; and LVGRS: after 6 cycles of chemotherapy < before chemotherapy. The results of Pearson correlation analysis showed that the dose of doxorubicin was negatively correlated with RVGCS, RVGLS, RVGRS, and LVGLS, but not with TAPSE, RVFAC, LVEF, and LVGRS. 3D-STI is helpful for early detection of the changes of left and right ventricular myocardial function after PAD chemotherapy in patients with multiple myeloma. And the early screening value of the RVGLS parameter is higher.

Incremental value of early systolic lengthening and postsystolic shortening in detecting left anterior descending artery stenosis using nonstress speckle-tracking echocardiography

The diagnosis of coronary artery disease (CAD) with nonstress echocardiography remains challenging. Although the assessment of either early systolic lengthening (ESL) or postsystolic shortening (PSS) allows the sensitive detection of CAD, it is unclear whether the integrated analysis of ESL and PSS in addition to the peak systolic strain can improve the diagnostic accuracy. We investigated the incremental value of ESL and PSS in detecting left anterior descending artery (LAD) stenosis using nonstress speckle-tracking echocardiography. Fifty-nine patients with significant LAD stenosis but without visual wall motion abnormalities on echocardiography at rest (30 single-vessel stenosis, 29 multivessel stenosis) and 43 patients without significant stenosis of any vessel were enrolled. The peak systolic strain, the time to ESL (T_ESL), and the time to PSS (T_PSS) were analyzed in all LAD segments, and the incremental values of the T_ESL and T_PSS in detecting LAD stenosis and the diagnostic accuracy were evaluated. In the apical anterior segment, the peak systolic strain was significantly lower and T_ESL and T_PSS were significantly longer in the single-vessel group than in the no stenosis group. In the single-vessel group, the addition of T_ESL and T_PSS to the peak systolic strain significantly increased the model power in detecting stenosis, and the integrated analysis improved diagnostic accuracy compared with the peak systolic strain alone. In contrast, this incremental value was not demonstrated in the multivessel group. The integrated analysis of the peak systolic strain, ESL, and PSS may allow better screening of single-vessel LAD stenosis using nonstress speckle-tracking echocardiography.

Myocardial Postsystolic Shortening and Early Systolic Lengthening: Current Status and Future Directions

The concept of paradoxical myocardial deformation, commonly referred to as postsystolic shortening and early systolic lengthening, was originally described in the 1970s when assessed by invasive cardiac methods, such as ventriculograms, in patients with ischemia and animal experimental models. Today, novel tissue-based imaging technology has revealed that these phenomena occur far more frequently than first described. This article defines these deformational patterns, summarizes current knowledge about their existence and highlights the clinical potential associated with their understanding.

Novel Estimation of Left Ventricular Filling Pressure Using 3-D Speckle-Tracking Echocardiography: Assessment in a Decompensated Systolic Heart Failure Model

E/e' allows for the non-invasive estimation of left ventricular (LV) filling pressure; however, Doppler malalignment can make the estimation unreliable, especially in dilated systolic failing hearts. The ratio of peak early diastolic filling rate to peak early diastolic global strain rate (FRe/SRe), which is a parameter derived from 3-D speckle-tracking echocardiography to estimate filling pressure, may be better applied in dilated systolic failing hearts because it can be obtained without the Doppler method. We investigated whether FRe/SRe could provide a better estimation of filling pressure than E/e' in 23 dogs with decompensated systolic heart failure induced by microembolization. FRe/SRe had better correlation coefficients with LV end-diastolic pressure (0.75-0.90) than did E/e' (0.40). The diagnostic accuracy of FRe/SRe in distinguishing elevated filling pressure was significantly higher than that of E/e'. This study indicates that FRe/SRe may provide a better estimation of LV filling pressure than E/e' in dilated systolic failing hearts.

The strain and strain rate imaging paradox in echocardiography: overabundant literature in the last two decades but still uncertain clinical utility in an individual case

Almost two decades ago strain and strain rate imaging were proposed as a new, potentially more sensitive modality for quantifying both regional and global myocardial function. Until now, however, strain and strain rate imaging have been slow to be incorporated into everyday clinical practice. More recently, two dimensional strain has been claimed as of greater clinical utility, given that it is angle independent, with improved feasibility and reproducibility as compared to tissue Doppler strain. Nevertheless, speckle tracking strain is reliant on 2D image quality and frame rates. Three dimensional speckle tracking could eliminate the problem of through-plane motion inherent in 2D imaging, but 3D strain is currently limited by low frame rates. Another limitation of strain imaging is that the results are dependent on the ultrasound machine on which analyses are performed, with variability in measurements between different vendors. Despite the diagnostic and prognostic advantages of 2D strain, there is a lack of specific therapeutic interventions based on strain and a paucity of long-term large-scale randomized trial evidence on cardiovascular outcomes. After overabundant literature the same definition of normal cut-off values is controversial and not univocal. Further studies are needed, involving both manufacturers and medical professionals, on the additive contribution, possibly different case by case, of interfering and artifactual factors, aside from myocardial function per se. These artifactual determinants and motion artifacts components could be dominant in individual cases and should always be taken into account in the clinical decision making process in a single case.

[Echocardiography in the Assessment of Postsystolic Shortening of the Left Ventricle Myocardium of the Heart]

Echocardiography allows evaluating left ventricular (LV) myocardial contractility; however, the visual assessment of contractility is subjective and requires considerable experience. Modern technologies for assessment of LV myocardial contractility, such as tissue Doppler and speckle-tracking echocardiography, provide quantitative estimation of various parameters of myocardial strain, including the LV postsystolic shortening. Several studies have demonstrated the value of postsystolic shortening for evaluation of myocardial ischemia and "ischemic memory" in patients with cardiovascular diseases. This review analyzes experimental and clinical studies that addressed LV postsystolic shortening.

Regional heterogeneity of afterload sensitivity in myocardial strain

PURPOSE

The peak systolic strain decreases due to afterload augmentation. However, its deterioration (i.e., afterload sensitivity) may be different within the left ventricular (LV) segments. We investigated how afterload influences regional strain and whether there is regional heterogeneity of afterload sensitivity.

METHODS

Afterload was increased by aortic banding in 20 open-chest dogs. Short-axis images were acquired at baseline and during banding. Circumferential strain was analyzed in six segments, and the absolute decrease in the peak systolic strain during banding (Δε) was calculated for each segment. To assess the effect of the compensatory preload recruitment during banding, the endocardial lengths of the septum and free wall were measured at end-diastole, and the rate of increase due to banding was calculated.

RESULTS

LV systolic pressure was significantly increased during banding (100 ± 14 vs. 143 ± 18 mmHg, P < 0.001). The peak systolic strain in all segments was significantly decreased during banding. Δɛ in the anterior segment, which is a part of the free wall, was significantly lower than that in the inferoseptal segment (2.6 ± 4.7 vs. 6.5 ± 3.5%, P = 0.035). The rate of increase in endocardial length in the free wall was significantly larger than that in the septum (15.6 ± 10.4 vs. 8.1 ± 7.4%, P = 0.014).

CONCLUSION

The decrease in septal strain during afterload augmentation was larger than that in free wall strain, indicating that there was regional heterogeneity of afterload sensitivity in circumferential strain. The larger compensatory preload recruitment in the free wall than in the septum is implicated as a cause of the heterogeneity.

Three-Dimensional Echocardiography - Role in Clinical Practice and Future Directions

Echocardiography has become an extension of the physical examination in cardiovascular practice. Frequently, it is used to confirm a clinical diagnostic suspicion. Another important role is to detect the underlying cardiovascular lesion to explain a patient's symptom complex or an abnormality found on chest radiography, electrocardiography, or cardiac enzyme tests. Patients are referred to the echocardiography laboratory because of their symptoms or due to non-specific laboratory abnormalities, and echocardiographers are expected to provide a definite diagnosis or a therapeutic clue. The introduction of the matrix array transducer into clinical practice allowed the acquisition of three-dimensional (3D) datasets. 3D echocardiography (3DE) has many advantages over 2-dimensional echocardiography, such as: (1) improved visualization of the complex shapes and spatial relations between cardiac structures; (2) improved quantification of the cardiac volumes and function; and (3) improved display and assessment of valve dysfunction. 3DE is increasingly utilized during routine clinical practice. This review article is aimed to examine the current clinical utility and future directions of 3DE.