Echocardiographic Assessment of Ventricular Synchrony in Congenital and Acquired Heart Disease in Children

Mechanical QT and JT intervals by M-mode echocardiography: An extrapolation from the concurrent electrocardiographic tracings

Background

Congenital long QT syndrome (CLQTS) is a life-threatening ion channelopathy leading to syncope and sudden death. Early diagnosis during the prenatal period and timely intervention can prevent sudden cardiac death and catastrophic consequences of this genetic ion channelopathy. Fetal magnetocardiography and fetal electrocardiography (ECG) enable the measurement of fetal QT and JT intervals, but their inherently technically challenging and/or resource-intensiveness nature preclude their routine clinical application. On the other hand, the high-temporal resolution of M-mode echocardiography makes it a well-suited and widely available modality for the measurement of cardiac events.

Aims and Objectives

We aimed to investigate the mechanical counterparts of the electrical QT and JT intervals on M-mode echocardiographic images of the tricuspid, mitral and aortic valves, and aortic wall.

Methods

We performed a prospective study on consecutive children referred to the outpatient pediatric cardiology clinic at a tertiary children's hospital. We defined M-mode echocardiographic landmark points on tracings of tricuspid annular planar systolic excursion, mitral and aortic valves, and aortic wall with simultaneous electrocardiographic recording. We measured the mean±SD of the absolute time difference and RR-adjusted time difference in cases with non-coincident ECG events and echocardiographic landmarks.

Results

Fifty healthy children were enrolled in the study. In 47 (94%) out of the 50 children, Q was coincident with the starting point of the tricuspid annular plane systolic excursion. In all children, the Q was coincident with the mid-point of the A-C line of the mitral valve. In 38 (76%) cases, there was a bump on the anterior wall of the aortic root immediately before the change in the slope of the aortic wall. This was coincident with the Q wave in 100% of cases. In all cases, the J point coincided with the point of acceleration of velocity on TAPSE. In all children, the J point coincided with the initial maximal opening of the aortic cusps. The end of the T wave occurred coincident with the peak of the tricuspid annular planar systolic excursion in 47 children (94%). In 48 children (96%), the end of the T wave coincided with the aortic cusps' closure point.

Conclusions

Based on our findings, we propose to measure the averaged mechanical QT and JT intervals by using an angled M-mode tracing of the aortic and mitral valve in five consecutive beats in the parasternal long-axis view. This is the first study on mechanical QT and JT intervals in healthy children. The study opens the horizons into the in-utero diagnosis of congenital long QT syndrome by measuring fetal QT and JT intervals using the widely available M-mode echocardiography.

Cardiac resynchronization therapy in paediatric patients with congenital heart disease: single centre with 10 years of experience

OBJECTIVES

In recent years, cardiac resynchronization therapy (CRT) has also started to be performed in the paediatric and CHD population. This study aimed to evaluate the efficacy of CRT in children with CHD.

PATIENTS AND METHODS

Patients with CHD who underwent CRT treatment in our paediatric cardiology clinic between January, 2010 and January, 2020 were included in the study. Demographic findings, 12-lead electrocardiograms, echocardiograms, clinical characteristics, management strategies, and outcomes were reviewed systematically.

RESULTS

The study population consisted of 18 CHD patients who had been treated with CRT for 10 years in our institution. The median age was 11 years (2.2-18 years) and the median weight was 39 kg (10-81 kg). Systemic ventricle was left ventricle in 13 patients, right ventricle in 4 patients, and 1 patient had single-ventricle physiology. CRT implantation indications were as follows: dysfunction after permanent pacemaker in 11 patients, dysfunction after left bundle branch block in 4 patients, and systemic ventricular dysfunction in 3 patients. CRT implantation techniques were epicardial (n = 13), hybrid (n = 4), and transvenous (n = 1) methods. QRS duration significantly decreased after CRT implantation (160 versus 124 m/second, p < 0.05). Median systemic ventricle ejection fraction (EF) significantly increased after the procedure (30 versus 50%, p < 0.05). Fourteen patients (78%) were responders, two patients (11%) were superresponders, and two patients (11%) were non-responders after the CRT treatment. One patient deceased during follow-up. Median follow-up duration was 40 months (6-117 months).

CONCLUSION

When electromechanical dyssynchrony occurs in paediatric cases with CHD and developing heart failure, patients should be evaluated in terms of CRT to improve ventricular function. Alternative CRT therapy will be beneficial in these cases that do not improve clinically despite optimal medical treatment.

Left Ventricular Myocardial Deformations in Hemodialysis Children by Speckle Tracking Echocardiography

Background:

Cardiac systolic dysfunction was potentially found in adult patients with end-stage renal disease (ESRD) who have preserved left ventricular ejection fraction (EF%). In children with ESRD, little data are available on early changes in myocardial function. This study aimed to detect the early changes in myocardial mechanics in pediatric patients with ESRD using speckle tracking echocardiography (STE).

Methods:

Thirty ESRD children receiving hemodialysis (HD) and30 age-matched controls were prospectively studied. Patients underwent echocardiographic studies before and after HD. Left ventricular longitudinal strain (LS), circumferential strain (CS), and radial strain (RS) myocardial deformation parameters (strain, strain rate) were evaluated by STE.

Results:

The LS was significantly reduced in pre-HD and post-HD patients compared with controls (P = .000). Controls showed the highest global longitudinal strain. The RS measurements did not differ significantly among the studied groups except for the inferior segment that is significantly reduced after HD compared with controls (P < .05). The CS was significantly reduced in pre-HD and post-HD patients compared with controls at the lateral and posterior segments (P = .035 and P = .013, respectively).

Conclusion:

Speckle-tracking echocardiography might detect early changes in myocardial mechanics in children with ESRD with preserved EF%.

Cardiac resynchronization and implantable defibrillators in adults with congenital heart disease

Cardiac resynchronization therapy (CRT) and implantable cardioverter defibrillators (ICDs) are well-established therapies for adult patients with heart failure that have been shown to improve morbidity and mortality. However, the benefits and indications for use in adults with congenital heart disease (ACHD) are less defined with no significant large prospective studies in this population. There are, however, multiple retrospective studies that demonstrate the efficacy of these devices in the ACHD population. These indicate a role for both CRT and ICDs in select patients with ACHD. The clinician and patient must balance the risks and benefits, summarized in complex evidence that reflects the heterogeneity of the ACHD patient group, and apply them in a patient-specific manner to optimize the utility of CRT and ICDs.

Effects of bone marrow mononuclear cells delivered through a graft vessel in patients with previous myocardial infarction and chronic heart failure: An echocardiographic study of left ventricular dyssynchrony

OBJECTIVES

Several trials are investigating the delivery of stem cells to treat ischemic cardiomyopathy. The aim of this study was the echocardiographic evaluation of the effectiveness of isolated coronary artery bypass graft (CABG) combined with bone marrow mononuclear cells (BMMNC) delivered through the graft vessels to improve left ventricular dyssynchrony in patients with previous myocardial infarction and chronic heart failure.

METHODS

42 patients with previous myocardial infarction and chronic heart failure were randomly allocated to either the CABG only group (n = 18) or the CABG with BMMNC graft group (n = 24group). We used 2D strain imaging to measure the absolute difference in time-to-peak radial strain between the earliest and the latest activated segments on LV short-axis images at the apical (RSTa), at the mitral annulus (RSTb), and at the papillary muscle (RSTm) level.

RESULTS

The effective rate of LV dyssynchrony improvement was significantly higher in the CABG + BMMNC than in the CABG only group (RSTb: 91.7% vs 50%, P < .05; RSTm: 78.6% vs 35.7%, P < .05; RSTa: 92.3% vs 50%, P < .05). The deterioration rate of LV synchrony was significantly lower in the CABG + BMMNC than in the CABG only group for RSTb (8.3% vs 70%, P < .05;) and RSTm (0 vs 50%, P < .05), but not for RSTa (18.2% vs 37.5%, P > .05).

CONCLUSIONS

Combining CABG with BMMNC delivering provided a better improvement of left ventricular dyssynchrony than CABG only.

Usefulness of right ventricular and right atrial two-dimensional speckle tracking strain to predict late arrhythmic events in adult patients with repaired Tetralogy of Fallot

OBJECTIVE

To determine whether right ventricular and/or atrial speckle tracking strain is associated with previous arrhythmic events in patients with repaired tetralogy of Fallot.

METHODS AND RESULTS

We studied right ventricular and atrial strain in 100 consecutive patients with repaired tetralogy of Fallot referred for routine echocardiographic evaluation. Patients were divided into two groups, one with previous documentation of arrhythmias (n=26) and one without arrhythmias, in a median follow-up of 22 years. Patients with arrhythmias were older (p<0.001) and had surgical repair at an older age (p=0.001). They also had significantly reduced right ventricular strain (-14.7±5.5 vs. -16.9±4.0%, p=0.029) and right atrial strain (19.1±7.7% vs. 25.8±11.4%, p=0.001). Neither right ventricular nor right atrial strain were independent predictors of the presence of a history of documented arrhythmias, which was associated with age at correction and with the presence of residual defects. In a subanalysis after excluding 23 patients who had had more than one corrective surgery, right ventricular strain was an independent predictor of the presence of previous arrhythmic events (OR 1.19, 95% CI 1.02-1.38, p=0.025). Right atrial strain was also an independent predictor after adjustment (OR 0.93, 95% CI 0.87-0.99, p=0.029). The ideal cut-off for right ventricular strain was -15.3% and for right atrial strain 23.0%.

CONCLUSIONS

Compared with conventional echocardiographic parameters, strain measures of the right heart are associated with the presence of arrhythmic events, and may be useful for risk stratification of patients with repaired tetralogy of Fallot, although a prospective study is required.

Longitudinal imaging of the ageing mouse

Several non-invasive imaging techniques are used to investigate the effect of pathologies and treatments over time in mouse models. Each preclinical in vivo technique provides longitudinal and quantitative measurements of changes in tissues and organs, which are fundamental for the evaluation of alterations in phenotype due to pathologies, interventions and treatments. However, it is still unclear how these imaging modalities can be used to study ageing with mice models. Almost all age related pathologies in mice such as osteoporosis, arthritis, diabetes, cancer, thrombi, dementia, to name a few, can be imaged in vivo by at least one longitudinal imaging modality. These measurements are the basis for quantification of treatment effects in the development phase of a novel treatment prior to its clinical testing. Furthermore, the non-invasive nature of such investigations allows the assessment of different tissue and organ phenotypes in the same animal and over time, providing the opportunity to study the dysfunction of multiple tissues associated with the ageing process. This review paper aims to provide an overview of the applications of the most commonly used in vivo imaging modalities used in mouse studies: micro-computed-tomography, preclinical magnetic-resonance-imaging, preclinical positron-emission-tomography, preclinical single photon emission computed tomography, ultrasound, intravital microscopy, and whole body optical imaging.

Strain and strain rate echocardiography in children with Wilson's disease

OBJECTIVE

This study aimed to evaluate strain and strain rate echocardiography in children with Wilson's disease to detect early cardiac dysfunction.

METHODS

In this study, 21 patients with Wilson's disease and a control group of 20 age- and gender-matched healthy children were included. All the patients and the control group were evaluated with two-dimensional (2D) and colour-coded conventional transthoracic echocardiography by the same paediatric cardiologist using the same echocardiography machine (Vivid E9, GE Healthcare, Norway) in standard precordial positions, according to the American Society of Echocardiography recommendations. 2D strain and strain rate echocardiography were performed after the ECG probes of the echocardiography machine were adjusted for ECG monitoring. Longitudinal, transverse and radial strain, and strain rate were assessed from six basal and six mid-ventricular segments of the left ventricle, as recommended by the American Society of Echocardiography.

RESULTS

Left ventricular wall thickness, systolic and diastolic diameters, left ventricular diameters normalised to body surface area, end-systolic and end-diastolic volumes, cardiac output and cardiac index values were within normal limits and statistically similar in the patient and control groups (p > 0.05). Global strain and strain rate: the patient group had a statistically significant lower peak A longitudinal velocity of the left basal point and peak E longitudinal velocity of the left basal (VAbasR) point, and higher global peak A longitudinal/circumferential strain rate (GSRa) compared to the corresponding values of the control group (p < 0.05). Radial strain and strain rate: end-systolic rotation [ROT (ES)] was statistically significantly lower in the patient group (p < 0.05). Longitudinal strain and strain rate: end-systolic longitudinal strain [SLSC (ES)] and positive peak transverse strain (STSR peak P) were statistically significantly lower in the patient group (p < 0.05). Segmental analysis showed that rotational strain measurement of the anterior and lateral segments of the patient group were statistically significantly lower than the corresponding values of the control group (p < 0.05). Segmental analysis showed statistically significantly lower values of endsystolic longitudinal strain [STSR (ES)] of the basal lateral (p < 0.05) and end-systolic longitudinal strain [SLSC (ES)] of the basal septal segment (p < 0.05) in the patient group. End-systolic longitudinal strain [SLSC (ES)] and positive peak transverse strain (STSR peak P) were statistically significantly lower in the patient group (p < 0.05). Segmental analysis showed statistically significantly lower values of endsystolic longitudinal strain [SLSC (ES)] of the mid-anterior and basal anterior segments (p < 0.05), end-systolic longitudinal strain [STSR (ES)] measurements of the posterior and mid-posterior segments, end-systolic longitudinal displacement [DLDC (ES)] of the basal posterior, mid-posterior and mid-antero-septal segments in the patient group.

CONCLUSION

Cardiac arrhythmias, cardiomyopathy and sudden cardiac death are rare complications but may be seen in children with Wilson's disease due to copper accumulation in the heart tissue. Strain and strain rate echocardiography is a relatively new and useful echocardiographic technique to evaluate cardiac function and cardiac deformation abnormalities. Our study showed that despite normal systolic function, patients with Wilson's disease showed diastolic dysfunction and regional deformation abnormalities, especially rotational strain and strain rate abnormalities.

Heart Failure Summit Review: cardiac re-synchronisation therapy in the failing heart

Extrapolating cardiac resynchronization therapy (CRT) to pediatric patients with heart failure has at times been difficult given the heterogeneity of pediatric cardiomyopathies, varying congenital heart disease (CHD) substrates, and the fact that most pediatric heart failure patients have right bundle branch block (RBBB) as opposed to LBBB. Yet, despite these limitations a number of multi-center retrospective studies in North America and Europe have identified some data to suggest that certain sub-populations tend to respond positively to CRT. In order to address some of the heterogeneity it is helpful to subdivide pediatric and young adult patients with CHD into four potential groups: (1) CRT for chronic RV pacing, (2) dilated cardiomyopathies, (3) pulmonary right ventricles, and (4) systemic right ventricles. The chronic RV paced group, especially long-standing RV apical pacing, with ventricular dyssynchrony has consistently shown to be the group that best responds to a proactive resynchronization course. CRT therapy in pulmonary right ventricles such as post-op tetralogy of Fallot have shown some promise and may be considered especially if there is evidence of concomitant left ventricular dysfunction with an electrical dyssynchrony. Patients with systemic right ventricles such as post-atrial baffle surgery or congenitally corrected transposition reportedly do well with CRT in the presence of both inter-ventricular and intra-ventricular dyssynchrony. There is little doubt that moving forward to best way to identify which pediatric patients with heart failure will respond to CRT, will require a collaborative effort between the electrophysiologist and the echocardiographer to identify appropriate candidates with electrical and mechanical dyssynchrony.

Echocardiographic assessment of ventricular function in pediatric patients: a comprehensive guide

Assessment of ventricular function is an important part of every echocardiographic examination. Specific pediatric guidelines on quantification of ventricular function are available, but technology evolves quickly and it generally takes long before newer techniques are integrated into routine clinical practice and are adopted by the guidelines. In the current overview, we would like to present our experience with integrating newer echocardiographic techniques for assessing ventricular function in children using a comprehensive state-of-the-art echocardiographic functional protocol. This protocol is used for specific patient populations such as pediatric patients with cardiomyopathy, post-transplant patients and oncology patients. We present the practical aspects of the protocols, their rationale and how this can be applied in clinical practice.

Pediatric echocardiography: new developments and applications

In this Special Issue of the Journal, 6 review articles that represent the new developments and applications of echocardiography for diagnosis and assessment of congenital heart disease from fetus to adult are included. The goal is to provide an updated review of the evidence for the current and potential use of some of the new methodologies, i.e. fetal echocardiography, tissue Doppler imaging, strain imaging by speckle tracking imaging, ventricular synchrony, quantification using real time three-dimensional (3D) echocardiography, and 3D echocardiography for adults with congenital heart disease. We hope this effort will provide an impetus for more investigation and ultimately clinical application of these new methodologies to improve the care of those with congenital and acquired heart diseases in the pediatric population and beyond.

Cardiac assessment in pediatric mice: strain analysis as a diagnostic measurement

Echocardiography is a robust tool for assessing cardiac function in both humans and laboratory animals. Conventional echocardiographic measurements, including chamber dimensions, wall thickness, and ejection fraction are routinely obtained to assess cardiac function in mice. Recently, myocardial strain and strain rate measurements have been added to functional assessments to provide additional details on regional abnormalities that are not evident using conventional measurements. To date, all studies of strain and strain rate in mice or rats have involved adult animals. This study serves to outline methods for acquiring echocardiographic images in pediatric mice and to provide myocardial strain and strain rate values for healthy C57BL/6J mice between 3 and 11 weeks old. Between weeks 3 and 11, left ventricular radial strain ranged from 32 to 43% and longitudinal strain ranged from -15 to -19%, with analysis over time showing no significant changes with aging (radial strain, P = 0.192 and longitudinal strain, P = 0.264; n = 4 for each time point evaluated). In conclusion, myocardial strain analysis in pediatric mice is technically feasible and has potential application in studying the pathophysiology of pediatric cardiovascular disease.