Positional localization: three-dimensional transthoracic echocardiographic techniques for the measurement of cardiac mass, volume, and function

The Role of METTL3-Mediated N6-Methyladenosine (m6A) of JPH2 mRNA in Cyclophosphamide-Induced Cardiotoxicity

Cyclophosphamide (CYP)-induced cardiotoxicity is a common side effect of cancer treatment. Although it has received significant attention, the related mechanisms of CYP-induced cardiotoxicity remain largely unknown. In this study, we used cell and animal models to investigate the effect of CYP on cardiomyocytes. Our data demonstrated that CYP-induced a prolonged cardiac QT interval and electromechanical coupling time courses accompanied by JPH2 downregulation. Moreover, N6-methyladenosine (m6A) methylation sequencing and RNA sequencing suggested that CYP induced cardiotoxicity by dysregulating calcium signaling. Importantly, our results demonstrated that CYP induced an increase in the m6A level of JPH2 mRNA by upregulating methyltransferases METTL3, leading to the reduction of JPH2 expression levels, as well as increased field potential duration and action potential duration in cardiomyocytes. Our results revealed a novel mechanism for m6A methylation-dependent regulation of JPH2, which provides new strategies for the treatment and prevention of CYP-induced cardiotoxicity.

Excitation-Contraction Coupling Time is More Sensitive in Evaluating Cardiac Systolic Function

Background:

Pressure overload-induced myocardial hypertrophy is a key step leading to heart failure. Previous cellular and animal studies demonstrated that deteriorated excitation–contraction coupling occurs as early as the compensated stage of hypertrophy before the global decrease in left ventricular ejection fraction (LVEF). This study was to evaluate the cardiac electromechanical coupling time in evaluating cardiac systolic function in the early stage of heart failure.

Methods:

Twenty-six patients with Stage B heart failure (SBHF) and 31 healthy controls (CONs) were enrolled in this study. M-mode echocardiography was performed to measure LVEF. Tissue Doppler imaging (TDI) combined with electrocardiography (ECG) was used to measure cardiac electromechanical coupling time.

Results:

There was no significant difference in LVEF between SBHF patients and CONs (64.23 ± 8.91% vs. 64.52 ± 5.90%; P = 0.886). However, all four electromechanical coupling time courses (Qsb: onset of Q wave on ECG to beginning of S wave on TDI, Qst: onset of Q wave on ECG to top of S wave on TDI, Rsb: top of R wave on ECG to beginning of S wave on TDI, and Rst: top of R wave on ECG to top of S wave on TDI) of SBHF patients were significantly longer than those of CONs (Qsb: 119.19 ± 35.68 ms vs. 80.30 ± 14.81 ms, P < 0.001; Qst: 165.42 ± 60.93 ms vs. 129.04 ± 16.97 ms, P = 0.006; Rsb: 82.43 ± 33.66 ms vs. 48.30 ± 15.18 ms, P < 0.001; and Rst: 122.37 ± 36.66 ms vs. 93.25 ± 16.72 ms, P = 0.001), and the Qsb, Rsb, and Rst time showed a significantly higher sensitivity than LVEF (Rst: P =0.032; Rsb: P = 0.003; and Qsb: P = 0.004).

Conclusions:

The cardiac electromechanical coupling time is more sensitive than LVEF in evaluating cardiac systolic function.

Assessment of left ventricular volumes and function by real time three-dimensional echocardiography in a pediatric population: a TomTec versus QLAB comparison

BACKGROUND

Three-dimensional echocardiography (3DE) allows accurate calculation of ventricular volumes despite a remaining geometric assumption on the ventricular shape. Few studies involving full volume reconstruction software have been performed on children. Our aim was to compare the left ventricular (LV) volume measurements obtained with the most used 3D analysis software in a pediatric population.

METHODS

Fifty patients (median age: 9.5 years) without cardiac disease were included in the study. 3DE was performed with the X4-2 or X7-2 matrix probe (ie33, Philips). The LV volume analysis was performed with QLAB 6.0 (semiautomated border detection) and TomTec 4D LV (primary manual tracking with semiautomated border detection).

RESULTS

TomTec analysis feasibility amounted to 94% whereas QLAB analysis feasibility only reached 80% (P = 0.037). The analysis time was shorter with QLAB than TomTec (5 ± 2 versus 6 ± 3 minutes, P < 0.05). The stroke volume, end diastolic and end systolic LV volume measurements performed on the 40 patients were strongly correlated (r > 0.97; P < 0.0001) with minimal bias. The LV ejection fraction was well correlated (r = 0.79; P < 0.0001).

CONCLUSION

3D LV volume quantification is feasible either by using manual or automated reconstruction software in a normal pediatric population. LV Measurements are well correlated. Differences in volume reconstruction algorithms provide specific software performance characteristics. TomTec is a more feasible method but requires a longer analysis time. Further studies are needed to validate the accuracy of the method to calculate enlarged LV volumes in patients with congenital heart diseases.

Hemodynamic improvement is faster after percutaneous ASD closure than after surgery

OBJECTIVES

Hemodynamic effects of surgical and percutaneous closure of atrial septal defect (ASD) were evaluated.

BACKGROUND

ASD causes volume overload of right ventricle (RV) and is associated with distortion and dysfunction of left ventricle (LV). The amount and timing of hemodynamic changes after ASD closure are not well known.

METHODS

The study group consisted of 7 children treated surgically and 17 treated in the catheterization laboratory. In the control group, there were 51 healthy children. RV size and LV end-diastolic and systolic dimensions, volumes, and function were examined by two- and three- dimensional echocardiography and serum concentrations of natriuretic peptides measured prior to ASD closure, and 1, 6, and 12 months thereafter.

RESULTS

In all children with ASD, during the 1-year follow-up, the z score of RV end-diastolic diameter decreased from a median 5.00 SD to 2.25 SD (P < 0.001). Dilatation of RV did not resolve entirely during 1-year follow-up in either treatment group. End-diastolic LV diameter increased from -1.50 to -0.50 SD (P < 0.001). LV size increased slower in the surgical subgroup but reached control levels in both groups. Concentrations of natriuretic peptides increased during the first month after ASD closure and normalized thereafter in patients treated percutaneously but remained higher than in controls in patients treated surgically.

CONCLUSIONS

During 1-year follow-up after ASD closure, RV size decreases but does not normalize in all patients. The size of the LV normalizes after ASD closure but the increase in LV size is slower in patients treated surgically. Serum levels of ANPN and proBNP are elevated prior to ASD closure but decrease thereafter to control levels in patients treated with the percutaneous technique but not in those treated surgically.

Live 3D Echocardiography: A Replacement for Traditional 2D Echocardiography?

OBJECTIVE

We describe the development of real-time 3D imaging and review the previously used versions of 3D echocardiography so that the reader will appreciate why current developments truly do represent a quantum leap in the technology.

CONCLUSION

Three-dimensional echocardiography has now been shown to have several advantages over 2D echocardiography, particularly for volume measurements, visualization of septal defects, and whole-valve evaluation. Given these data, it is clear that 3D echocardiography is here to stay and soon will become part of routine echocardiographic examinations.

A visual approach for the accurate determination of echocardiographic left ventricular ejection fraction by medical students

BACKGROUND

Previously published reports show that there is significant intraobserver, interobserver, and interinstitutional variability in the determination of left ventricular (LV) ejection fraction (EF) by echocardiography. With the increased deployment of echocardiography (eg, handheld devices), there exists a need for developing a simple, intuitive approach for evaluating LVEF that allows a wider range of physicians to accurately and rapidly determine LVEF.

OBJECTIVE

We sought to create a system for assessing LVEF that relies on recognition and matching of patterns, rather than on mathematic calculations and geometric assumptions.

METHODS

A library of videoclips of cardiac function was compiled from 54 patients who spanned the spectrum of LVEF. LVEFs were calculated for these patients using standard echocardiographic methods, with further validation of a subsample using cardiac magnetic resonance imaging measurement of LVEF. The library of images was used to create a software tool for assessing LVEF on the basis of a "template-matching" approach. The software tool was then tested on medical students (N=13) to determine whether it enabled relatively untrained individuals to make accurate LVEF estimates.

RESULTS

Using a template-matching approach for interpretation of echocardiograms, medical students were able to accurately estimate LVEF after only a limited introduction to echocardiography. Their LVEF estimates showed good correlation and agreement with gold standard (r = 0.88, standard square of the estimate = 6.0, limits of agreement = +12.0%, -15.6%).

CONCLUSIONS

A new visual approach for assessing cardiac function using template matching can accurately estimate LVEF. With minimal training, medical students can make LVEF estimates that correlate well with gold standard. The application of this new approach includes allowing for the interpretation of LVEF from echocardiograms to be performed by a broader spectrum of physicians.