Characterization of Left Ventricular Diastolic Function by Tissue Doppler Imaging and Clinical Status in Children With Hypertrophic Cardiomyopathy

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Unique Aspects of Hypertrophic Cardiomyopathy in Children

Hypertrophic cardiomyopathy (HCM) is a primary heart muscle disease characterized by left ventricular hypertrophy that can be asymptomatic or with presentations that vary from left ventricular outflow tract obstruction, heart failure from diastolic dysfunction, arrhythmias, and/or sudden cardiac death. Children younger than 1 year of age tend to have worse outcomes and often have HCM secondary to inborn errors of metabolism or syndromes such as RASopathies. For children who survive or are diagnosed after 1 year of age, HCM outcomes are often favourable and similar to those seen in adults. This is because of sudden cardiac death risk stratification and medical and surgical innovations. Genetic testing and timely cardiac screening are paving the way for disease-modifying treatment as gene-specific therapies are being developed.

Modeling the Relationship Between Diastolic Phenotype and Outcomes in Pediatric Hypertrophic Cardiomyopathy

BACKGROUND

Pediatric hypertrophic cardiomyopathy (HCM) is associated with adverse events. The contribution of diastolic dysfunction to adverse events is poorly understood. The aim of this study was to explore the association between diastolic phenotype and outcomes in pediatric patients with HCM.

METHODS

Children <18 years of age with diagnosed with HCM were included. Diastolic function parameters were measured from the first echocardiogram at the time of diagnosis, including Doppler flow velocities, tissue Doppler velocities, and left atrial volume and function. Using principal-component analysis, key features in echocardiographic parameters were identified. The principal components were regressed to freedom from major adverse cardiac events (MACE), defined as implantable cardioverter-defibrillator insertion, myectomy, aborted sudden cardiac death, transplantation, need for mechanical circulatory support, and death.

RESULTS

Variables that estimate left ventricular filling pressures were highly collinear and associated with MACE (hazard ratio, 0.86; 95% CI, 0.75-1.00), though this was no longer significant after controlling for left ventricular thickness and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with outcomes in the covariate-adjusted model (hazard ratio, 0.69; 95% CI, 0.5-0.94). The covariate-adjusted model had an Akaike information criterion of 213, an adjusted R2 value of 0.78, and a concordance index of 0.82 for association with MACE.

CONCLUSION

Echocardiographic parameters of diastolic dysfunction were associated with MACE in this population study, in combination with the severity of left ventricular hypertrophy and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with adverse events. Additional study of diastolic function parameters adjusted for patient size could facilitate the prediction of adverse events in pediatric patients with HCM.

Role of Imaging in the Diagnosis, Evaluation, and Management of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is increasingly recognized and may benefit from the recent approval of new, targeted medical therapy. Successful management of HCM is dependent on early and accurate diagnosis. The lack of a definitive diagnostic test, the wide variation in phenotype and the commonness of phenocopy conditions, and the presence of normal or hyperdynamic left ventricular function in most patients makes HCM a condition that is highly dependent on imaging for all aspects of management including, diagnosis, classification, predicting risk of complications, detecting complications, identifying risk for ventricular arrhythmias, evaluating choice of therapy and monitoring therapy, intraprocedural guidance, and screening family members. Although echocardiographic imaging remains the mainstay in the diagnosis and subsequent management of HCM, this disease clearly requires multimethod imaging for various aspects of optimal patient care. Advances in echocardiography hardware and techniques, development and refinement of imaging with computed tomography, magnetic resonance, and nuclear scanning, and the emergence of very focused assessments such as diastology and fibrosis imaging have all advanced the diagnosis and management of HCM. In this review, we discuss the relative utility and evidence support for these imaging approaches to contribute to improve patient outcomes.

Multimodality Imaging in Patients with Hypertrophic Cardiomyopathy and Atrial Fibrillation

Ventricular hypertrophy is associated with diastolic dysfunction, resulting in increased left atrial (LA) pressure, enlargement, fibrosis, and decreased LA function. Hypertrophic cardiomyopathy (HCM) is characterized by myocyte disarray, myocardial fibrosis, and hypertrophy. Notably, a thickened and noncompliant LV results in the impairment of diastolic function. These conditions promote LA remodeling and enlargement, which contribute to developing and maintaining atrial fibrillation (AF). AF is an atrial arrhythmia that occurs frequently in HCM, and evaluating the morphology and physiology of the atrium and ventricle is important for treatment and prognosis determination in HCM patients with AF. In addition, it provides a clue that can predict the possibility of new AF, even in patients not previously diagnosed with AF. Cardiac magnetic resonance (CMR), which can overcome the limitations of transthoracic echocardiography (TTE), has been widely used traditionally and even enables tissue characterization; moreover, it has emerged as an essential imaging modality for patients with HCM. Here, we review the role of multimodal imaging in patients with HCM and AF.

Reference data for left ventricular filling and atrial function in children using cardiovascular magnetic resonance

BACKGROUND

Diastolic dysfunction is associated with morbidity and mortality in multiple pediatric disease processes. Cardiovascular magnetic resonance (CMR) provides a non-invasive method of studying left ventricular (LV) diastolic dysfunction through the assessment of LV filling curves and left atrial (LA) volume and function. However, there are no normative data for LV filling curves and the standard method is time-intensive. This study aims to compare an alternate, more rapid method of obtaining LV filling curves to standard methodology and report normative CMR diastolic function data for LV filling curves and LA volumes and function.

METHODS

Ninety-six healthy pediatric subjects (14.3 ± 3.4 years) with normal CMR defined by normal biventricular size and systolic function without late gadolinium enhancement were included. LV filling curves were generated by removing basal slices without myocardium present throughout the cardiac cycle and apical slices with poor endocardial delineation (compressed method), then re-generated including every phase of myocardium from apex to base (standard method). Indices of diastolic function included peak filling rate and time to peak filling. Systolic metrics included peak ejection rate and time to peak ejection. Both peak ejection and peak filling rates were indexed to end-diastolic volume. LA maximum, minimum and pre-contraction volumes were calculated using a biplane method. Inter-and intra-observer variability were assessed with intraclass correlation coefficient. Multivariable linear regression was used to assess the effects of body surface area (BSA), gender and age on metrics of diastolic function.

RESULTS

BSA had the largest effect on LV filling curves. Normal LV filling data are reported for both compressed and standard methods. The time to perform the compressed method was significantly shorter than the standard method (median 6.1 min vs. 12.5 min, p < 0.001). Both methods had strong to moderate correlation for all metrics. Intra-observer reproducibility was moderate to high for all LV filling and LA metrics except for time to peak ejection and peak filling.

CONCLUSIONS

We report reference values for LV filling metrics and LA volumes. The compressed method is more rapid and produces similar results to standard methodology, which may facilitate the use of LV filling in clinical CMR reporting.

Indications and management of implantable cardioverter-defibrillator therapy in childhood hypertrophic cardiomyopathy

Sudden cardiac death is the most common mode of death during childhood and adolescence in hypertrophic cardiomyopathy, and identifying those individuals at highest risk is a major aspect of clinical care. The mainstay of preventative therapy is the implantable cardioverter-defibrillator, which has been shown to be effective at terminating malignant ventricular arrhythmias in children with hypertrophic cardiomyopathy but can be associated with substantial morbidity. Accurate identification of those children at highest risk who would benefit most from implantable cardioverter-defibrillator implantation while minimising the risk of complications is, therefore, essential. This position statement, on behalf of the Association for European Paediatric and Congenital Cardiology (AEPC), reviews the currently available data on established and proposed risk factors for sudden cardiac death in childhood-onset hypertrophic cardiomyopathy and current approaches for risk stratification in this population. It also provides guidance on identification of individuals at risk of sudden cardiac death and optimal management of implantable cardioverter-defibrillators in children and adolescents with hypertrophic cardiomyopathy.

Impact of Ventricular Geometric Characteristics on Myocardial Stiffness Assessment Using Shear-Wave Velocity in Healthy Children and Young Adults

BACKGROUND

Diastolic myocardial stiffness (MS) can serve as a key diagnostic parameter for congenital or acquired heart diseases. Using shear modulus and shear-wave velocity (SWV), shear-wave elastography (SWE) is an emerging ultrasound-based technique that can allow noninvasive assessment of MS. However, MS extrinsic parameters such as left ventricular geometric characteristics could affect shear-wave propagation. The aims of this study were to determine a range of normal values of MS using SWE in age groups of healthy children and young adults and to explore the impact of left ventricular geometric characteristics on SWE.

METHODS

Sixty healthy volunteers were recruited in the study and divided into 2 groups: neonates (0-1 months old, n = 15) and >1 month old (1 month to 45 years of age, n = 45). SWE was performed using the Verasonics Vantage systems with a phased-array ultrasound probe. The anteroseptal basal segment was assessed in two views. SWE was electrocardiographically triggered during the end-diastolic phase. Conventional echocardiography was performed to assess ventricular function and anatomy. Results are presented as stiffness values along with mean velocity measurements and SDs. Simple and multivariate linear regression analyses were performed.

RESULTS

For neonates, mean MS was 1.87 ± 0.79 kPa (range, 0.59-2.91 kPa; mean SWV, 1.37 ± 0.57 m/sec), with high variability and no correlation with age (P = .239). For this age group, no statistically significant correlation was found between MS and any demographic or echocardiographic parameters (P > .05). For the >1 month old group, a mean MS value of 1.67 ± 0.53 kPa was observed (range, 0.6-3 kPa; mean SWV, 1.29 ± 0.49 m/sec) for healthy volunteers. When paired for age, no sex-related difference was observed (P = .55). In univariate linear regression analysis, age (r = 0.83, P < .01), diastolic interventricular septal thickness (r = 0.72, P < .01), and left ventricular end-diastolic diameter (r = 0.67, P < .01) were the parameters with the highest correlation coefficients with MS. In a multiple linear regression analysis incorporating these three parameters as cofounding factors, age was the only statistically significant parameters (r = 0.81, P = .02).

CONCLUSION

Diastolic MS increases linearly in children and young adults. Diastolic MS correlates more robustly with age than with myocardial and left ventricular geometric characteristics. However, the geometry affects SWV, implying the need to determine well-established boundaries in future studies for the clinical application of SWE.

Left atrial phasic volumes and functions changes in asymptomatic patients with sarcoidosis: evaluation by three-dimensional echocardiography

BACKGROUND

Cardiac involvement is the leading cause of morbidity and death in patients with sarcoidosis. However, many patients remain asymptomatic until the late-stage. In this study, we investigated the left atrial (LA) phasic volumes and functions changes by three-dimensional (3D) echocardiography measurements in asymptomatic patients with sarcoidosis, which has good correlation with cardiac magnetic resonance imaging.

METHODS

In this cross-sectional study, 44 asymptomatic patients with sarcoidosis and 40 age, sex and BMI-matched healthy volunteers underwent two-dimensional (2D) and 3D-echocardiograpy. Standard echocardiographic and tissue Doppler imaging parameters were obtained. LA phasic volumes were assessed by 3D-echocardiography. From the 3D-echocardiography derived values, LA active, passive, and total emptying fraction (EF) were calculated.

RESULTS

All left ventricular ejection fractions (LVEF) obtained by 2D and 3D-echocardiography were normal (≥50%). While LA diameters (33.36 ± 4.23 vs. 30.57 ± 5.43) and E/e' septal annulus ratios (10.82 ± 1.79 vs. 9.27 ± 1.81) were significantly higher, A-wave (70.80 ± 5.81 vs. 74.51 ± 5.41) and e'septal annular velocities (6.48 ± 1.58 vs. 9.03 ± 1.63) were significantly lower in the sarcoidosis group as compared with control group, respectively. While 3D-echocardiography derived LA-minimum volume indices (LAVImin) (13.89 ± 2.75 vs. 12.23 ± 1.73) were significantly higher, 3D-echocardiography derived LA active EFs (AAEF) (30.78 ± 3.52 vs. 38.52 ± 4.75) and LA total EFs (TAEF) (47.71 ± 7.47 vs. 53.32 ± 5.81) were found to be significantly lower in the sarcoidosis group as compared with control group, respectively.

CONCLUSION

LAVImin, AAEF and TAEF calculated based on LA phasic volumes obtained by 3D-echocardiography may be promising indicators of subclinical cardiac involvement in asymptomatic patients with sarcoidosis.

Exploring the Possible Impact of Echocardiographic Diastolic Function Parameters on Outcome in Paediatric Dilated Cardiomyopathy

Diastolic dysfunction is an important determinant for prognosis and survival in several paediatric heart diseases. We aimed to explore its possible impact on outcome in children with dilated cardiomyopathy. From 2006 to 2016, children less than 18 years old with dilated cardiomyopathy were retrospectively enrolled. Echocardiographic diastolic function parameters and child outcomes were analysed. Of 43 children aged 0.2 to 16.1 years old referred with dilated cardiomyopathy, 8 patients required cardiac transplant or mechanical assist devices (18%), 24 had persistently abnormal left ventricular function and/or dilatation (56%) and 11 patients recovered (26%). There was no significant difference in mitral velocities on Tissue Doppler Imaging, mitral valve inflow velocities, isovolumic relaxation time, left atrial area z-score and mitral lateral E/e' ratios between patients with recovery and patients with disease progression or persistently abnormal ventricular function and/or dilation. This is the first study on childhood dilated cardiomyopathy to address individual echocardiographic diastolic function parameters and their association to recovery. In this study, echocardiographic parameters for diastolic function did not predict recovery.

Recommendations for Multimodality Cardiovascular Imaging of Patients with Hypertrophic Cardiomyopathy: An Update from the American Society of Echocardiography, in Collaboration with the American Society of Nuclear Cardiology, the Society for Cardiovascular Magnetic Resonance, and the Society of Cardiovascular Computed Tomography

Hypertrophic cardiomyopathy (HCM) is defined by the presence of left ventricular hypertrophy in the absence of other potentially causative cardiac, systemic, syndromic, or metabolic diseases. Symptoms can be related to a range of pathophysiologic mechanisms including left ventricular outflow tract obstruction with or without significant mitral regurgitation, diastolic dysfunction with heart failure with preserved and heart failure with reduced ejection fraction, autonomic dysfunction, ischemia, and arrhythmias. Appropriate understanding and utilization of multimodality imaging is fundamental to accurate diagnosis as well as longitudinal care of patients with HCM. Resting and stress imaging provide comprehensive and complementary information to help clarify mechanism(s) responsible for symptoms such that appropriate and timely treatment strategies may be implemented. Advanced imaging is relied upon to guide certain treatment options including septal reduction therapy and mitral valve repair. Using both clinical and imaging parameters, enhanced algorithms for sudden cardiac death risk stratification facilitate selection of HCM patients most likely to benefit from implantable cardioverter-defibrillators.

Therapeutic Approaches in Heart Failure with Preserved Ejection Fraction (HFpEF) in Children: Present and Future

For a long time, pediatric heart failure (HF) with preserved systolic function (HFpEF) has been noted in patients with cardiomyopathies and congenital heart disease. HFpEF is infrequently reported in children and instead of using the  HFpEF terminology the HF symptoms are attributed to diastolic dysfunction. Identifying HFpEF in children is challenging because of heterogeneous etiologies and unknown pathophysiological mechanisms. Advances in echocardiography and cardiac magnetic resonance imaging techniques have further increased our understanding of HFpEF in children. However, the literature does not describe the incidence, etiology, clinical features, and treatment of HFpEF in children. At present, treatment of HFpEF in children is extrapolated from clinical trials in adults. There are significant differences between pediatric and adult HF with reduced ejection fraction, supported by a lack of adequate response to adult HF therapies. Evidence-based clinical trials in children are still not available because of the difficulty of conducting trials with a limited number of pediatric patients with HF. The treatment of HFpEF in children is based upon the clinician's experience, and the majority of children receive off-level medications. There are significant differences between pediatric and adult HFpEF pharmacotherapies in many areas, including side-effect profiles, underlying pathophysiologies, the β-receptor physiology, and pharmacokinetics and pharmacodynamics. This review describes the present and future treatments for children with HFpEF compared with adults. This review also highlights the need to urgently test new therapies in children with HFpEF to demonstrate the safety and efficacy of drugs and devices with proven benefits in adults.

Relationship Between Maximal Left Ventricular Wall Thickness and Sudden Cardiac Death in Childhood Onset Hypertrophic Cardiomyopathy

BACKGROUND

Maximal left ventricular wall thickness (MLVWT) is a risk factor for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). In adults, the severity of left ventricular hypertrophy has a nonlinear relationship with SCD, but it is not known whether the same complex relationship is seen in childhood. The aim of this study was to describe the relationship between left ventricular hypertrophy and SCD risk in a large international pediatric HCM cohort.

METHODS

The study cohort comprised 1075 children (mean age, 10.2 years [±4.4]) diagnosed with HCM (1-16 years) from the International Paediatric Hypertrophic Cardiomyopathy Consortium. Anonymized, noninvasive clinical data were collected from baseline evaluation and follow-up, and 5-year estimated SCD risk was calculated (HCM Risk-Kids).

RESULTS

MLVWT Z score was <10 in 598 (58.1%), ≥10 to <20 in 334 (31.1%), and ≥20 in 143 (13.3%). Higher MLVWT Z scores were associated with heart failure symptoms, unexplained syncope, left ventricular outflow tract obstruction, left atrial dilatation, and nonsustained ventricular tachycardia. One hundred twenty-two patients (71.3%) with MLVWT Z score ≥20 had coexisting risk factors for SCD. Over a median follow-up of 4.9 years (interquartile range, 2.3-9.3), 115 (10.7%) had an SCD event. Freedom from SCD event at 5 years for those with MLVWT Z scores <10, ≥10 to <20, and ≥20 was 95.6%, 87.4%, and 86.0, respectively. The estimated SCD risk at 5 years had a nonlinear, inverted U-shaped relationship with MLVWT Z score, peaking at Z score +23. The presence of coexisting risk factors had a summative effect on risk.

CONCLUSIONS

In children with HCM, an inverted U-shaped relationship exists between left ventricular hypertrophy and estimated SCD risk. The presence of additional risk factors has a summative effect on risk. While MLVWT is important for risk stratification, it should not be used either as a binary variable or in isolation to guide implantable cardioverter defibrillator implantation decisions in children with HCM.

What Aspects of Phenotype Determine Risk for Sudden Cardiac Death in Pediatric Hypertrophic Cardiomyopathy?

Sudden cardiac death due to hypertrophic cardiomyopathy (HCM), is the most common autopsy-proven cause of unexpected medical death in children after infancy. This mode of death is preventable by implantation of an internal cardiac defibrillator (ICD), a procedure that has considerable morbidity in childhood patients, and even mortality. Since HCM is an inheritable disease (usually autosomal dominant, occasionally recessive), family screening may identify subjects at risk. This review summarizes published studies carried out to identify which phenotypic markers are important risk factors in childhood patients with HCM and reviews the performance of existing risk-stratification algorithms (HCM Risk-Kids, PRIMaCY) against those of single phenotypic markers. A significant proportion of HCM-patients diagnosed in childhood are associated with RASopathies such as Noonan syndrome, but a knowledge gap exists over risk stratification in this patient group. In conclusion, pediatric risk-stratification algorithms for sudden cardiac death perform better in children than adult HCM risk-stratification strategies. However, current multivariable algorithms overestimate risk substantially without having high sensitivity, and remain ‘a work in progress’. To include additional phenotypic parameters that can be reproducibly measured such as ECG-markers, e.g., ECG risk score (which has high sensitivity and negative predictive value), tissue Doppler diastolic function measurements, and quantification of myocardial scarring on cardiac magnetic resonance imaging, has the potential to improve risk-stratification algorithms. Until that work has been achieved, these are three factors that the clinician can combine with the current algorithm-calculated per cent risk, in order better to assess risk.

Pediatric Hypertrophic Cardiomyopathy: Exploring the Genotype-Phenotype Association

Pediatric hypertrophic cardiomyopathy (HCM) is the most common form of cardiomyopathy in children and a leading cause of sudden cardiac death. Yet, the association between genotype variation, phenotype expression, and adverse events in pediatric HCM has not been fully elucidated. Although the literature on this topic is evolving in adult HCM, the evidence in children is lacking. Solidifying our understanding of this relationship could improve risk stratification as well as improve our comprehension of the underlying pathophysiological characteristics of pediatric HCM. In this state-of-the-art review, we examine the current literature on genetic variations in HCM and their association with outcomes in children, discuss the current approaches to identifying cardiovascular phenotypes in pediatric HCM, and explore possible avenues that could improve sudden cardiac death risk assessment.

Factors associated with the risk of cardiac death in children with hypertrophic cardiomyopathy: a systematic review and meta-analysis

BACKGROUND

Studies on risk factors of sudden cardiac death (CD) or CD in children with hypertrophic cardiomyopathy (HCM) are lacking.

OBJECTIVES

To assess factors associated with the risk of sudden CD or CD in HCM children.

METHODS

Pubmed, Embase, Cochrane Library, and Web of Science databases were searched.

RESULTS

The results indicated that children with previous adverse cardiac events during childhood and with a history of syncope had an increased risk of sudden CD or CD. Non-sustained ventricular tachycardia (VT) in HCM children was associated with sudden CD or CD. Children with left ventricular hypertrophy (LVH) were at higher risk of sudden CD or CD. And left ventricular outflow tract (LVOT) obstruction was a potential risk factor for sudden CD in children with HCM (all P<0.05).

CONCLUSION

Optimal care and appropriate monitoring is necessary for HCM children with higher risk of sudden CD or CD.

Management of cardiac aspects in children with Noonan syndrome - results from a European clinical practice survey among paediatric cardiologists

BACKGROUND

The majority of children with Noonan syndrome (NS) or other diseases from the RASopathy spectrum suffer from congenital heart disease. This study aims to survey cardiac care of this patient cohort within Europe.

METHODS

A cross-sectional exploratory survey assessing the treatment and management of patients with NS by paediatric endocrinologists, cardiologists and clinical geneticists was developed. This report details responses of 110 participating paediatric cardiologists from multiple countries.

RESULTS

Most paediatric cardiologists responding to the questionnaire were associated with university hospitals, and most treated <10 patients/year with congenital heart disease associated with the NS spectrum. Molecular genetic testing for diagnosis confirmation was initiated by 81%. Half of the respondents reported that patients with NS and congenital heart disease typically present <1y of age, and that a large percentage of affected patients require interventions and pharmacotherapy early in life. A higher proportion of infant presentation and need for pharmacotherapy was reported by respondents from Germany and Sweden than from France and Spain (p = 0.031; p = 0.014; Fisher's exact test). Older age at first presentation was reported more from general hospitals and independent practices than from university hospitals (p = 0.031). The majority of NS patients were followed at specialist centres, but only 37% reported that their institution offered dedicated transition clinic to adult services. Very few NS patients with hypertrophic cardiomyopathy (HCM) were reported to carry implantable cardioverter defibrillators for sudden cardiac death prevention. Uncertainty was evident in regard to growth hormone treatment in patients with NS and co-existing HCM, where 13% considered it not a contra-indication, 24% stated they did not know, but 63% considered HCM either a possible (20%) or definite (15%) contraindication, or a cause for frequent monitoring (28%). Regarding adverse reactions for patients with NS on growth hormone therapy, 5/19 paediatric cardiology respondents reported a total of 12 adverse cardiac events.

CONCLUSIONS

Congenital heart disease in patients with NS or other RASopathies is associated with significant morbidity during early life, and specialty centre care is appropriate. More research is needed regarding the use of growth hormone in patients with NS with congenital heart disease, and unmet medical needs have been identified.

Left Atrial Strain and Function in Pediatric Hypertrophic Cardiomyopathy

BACKGROUND

Left atrial (LA) strain and dysfunction are early markers of diastolic dysfunction, associated with poor exercise capacity in adults with hypertrophic cardiomyopathy (HCM). Literature on assessment of LA mechanics in pediatric HCM is lacking. The aim of this study was to assess LA strain and LA function in pediatric patients who have HCM with (phenotype positive [P+]) and without (genotype positive, phenotype negative [G+P-]) ventricular hypertrophy and evaluate their correlation with exercise stress test parameters.

METHODS

Seventy-eight children (3-25 years of age) with HCM (P+, n = 46; G+P-, n = 32) and 20 healthy control subjects were retrospectively studied. LA conduit function, reservoir function, and pump function were computed using phasic LA volumetric analysis. LA reservoir strain (LASr) and LA contractile strain were measured using speckle-tracking echocardiography. Exercise test findings within 12 months of echocardiography were recorded.

RESULTS

LA conduit function (36% vs 48%, P < .001) and LA reservoir function (137% vs 180%, P < .001) were lower in P+ than in G+P- patients. LA contractile function did not differ between the groups (31% vs 32%, P = .87). Compared with patients with G+P- HCM, those with P+HCM had lower four-chamber LASr (29% vs 41%, P < .001), two-chamber LASr (30% vs 41%, P < .001), average LASr (29% vs 42%, P < .001), and LA contractile strain (9% vs 12%, P = .016). In the cohort of patients with HCM who underwent stress testing (n = 35), LA conduit function weakly correlated with aerobic capacity (r = 0.42, P = .019).

CONCLUSIONS

Children with P+HCM have reduced LA function, measurable by both volumetric and strain analysis. Altered LA mechanics are associated with poor exercise capacity. This study lays the foundation for the evaluation of novel LA parameters in pediatric HCM and warrants larger longitudinal studies to assess its clinical significance.

Newer risk assessment strategies in hypertrophic cardiomyopathy

PURPOSE OF REVIEW

The present article serves to review current risk assessment guidelines for sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM) and to discuss how these guidelines can be applied to patients with childhood HCM. New diagnostic techniques that could lead to more accurate risk assessment tools are also discussed.

RECENT FINDINGS

Current guidelines for risk assessment in childhood HCM are extrapolated from adult guidelines and lack background research to validate their use. Continuous variables, such as wall thickness, are converted to binary variables, which is particularly concerning in pediatric patients' where weight gain and linear growth is likely to lead to more significant hemodynamic changes in shorter periods of time. Some studies have even shown that risk factors concerning in adults may actually be protective in pediatric patients. Additionally, large gaps still remain between genotype and phenotype expression in HCM.

SUMMARY

A better understanding of the relationship between cause, phenotype, and outcomes is needed to truly be able to determine risk for SCD in childhood HCM. Larger studies, including newer technologies and quantitative models, similar to the European HCM Risk-SCD model, which allows for a quantitative risk diagnosis, are needed as well.

Smith-Magenis syndrome: Report of morphological and new functional cardiac findings with review of the literature

Smith-Magenis syndrome (SMS) is a genetic disorder characterized by multiple congenital anomalies, sleep disturbance, behavioral impairment, and intellectual disability. Its genetic cause has been defined as an alteration in the Retinoic Acid-Induced 1 gene. Cardiac anomalies have been reported since the first description of this condition in patients with 17p11.2 deletion. Variable cardiac defects, including ventricular septal defects, atrial septal defects, tricuspid stenosis, mitral stenosis, tricuspid and mitral regurgitation, aortic stenosis, pulmonary stenosis, mitral valve prolapse, tetralogy of Fallot, and total anomalous pulmonary venous connection, have been anecdotally reported and systematic case series are still lacking. Herein, we define the spectrum of the cardiac phenotype and describe for the first time the cardiac function in a large cohort of pediatric patients with SMS. Revision of the literature and correlations between genotype and cardiac phenotype was performed.

Association between genetic variants in the HIF1A-VEGF pathway and left ventricular regional myocardial deformation in patients with hypertrophic cardiomyopathy

BACKGROUND

Information on genetic etiology of pediatric hypertrophic cardiomyopathy (HCM) rarely aids in risk stratification and prediction of disease onset. Little data exist on the association between genetic modifiers and phenotypic expression of myocardial performance, hampering an individual precision medicine approach.

METHODS

Single-nucleotide polymorphism genotyping for six previously established disease risk alleles in the hypoxia-inducible factor-1α-vascular endothelial growth factor pathway was performed in a pediatric cohort with HCM. Findings were correlated with echocardiographic parameters of systolic and diastolic myocardial deformation measured by two-dimensional (2-D) speckle-tracking strain.

RESULTS

Twenty-five children (6.1 ± 4.5 years; 69% male) with phenotypic and genotypic (60%) HCM were included. Out of six risk alleles tested, one, VEGF1 963GG, showed an association with reduced regional systolic and diastolic left ventricular (LV) myocardial deformation. Moreover, LV average and segmental systolic and diastolic strain and strain rate were significantly reduced, as assessed by the standardized difference, in patients harboring the risk allele.

CONCLUSIONS

This is the first study to identify an association between a risk allele in the VEGF pathway and regional LV myocardial function, with the VEGF1 963GG allele associated with reduced LV systolic and diastolic myocardial performance. While studies are needed to link this information to adverse clinical outcomes, this knowledge may help in risk stratification and patient management in HCM.

IMPACT

Risk allele in the VEGF gene impacts on LV myocardial deformation phenotype in children with HCM. LV 2-D strain is significantly reduced in patients with risk allele compared to non-risk allele patients within HCM patient groups. Describes that deficiencies in LV myocardial performance in children with HCM are associated with a previously identified risk allele in the angiogenic transcription factor VEGF. First study to identify an association between a risk allele in the VEGF pathway and regional LV myocardial deformation measured by 2-D strain in children with HCM.

Left ventricular long-axis function in hypertrophic cardiomyopathy - Relationships between e`, early diastolic excursion and duration, and systolic excursion

Background

The peak velocity of early diastolic mitral annular motion (e`) is believed to provide sensitive detection of left ventricular (LV) diastolic dysfunction in hypertrophic cardiomyopathy (HCM), but other aspects of LV long-axis function in HCM have received less attention. Systolic mitral annular excursion (SExc) is also reduced in HCM and must be an intrinsic limitation to the extent of the subsequent motion during diastole. However, the effects of HCM on excursion during early diastole (EDExc) and atrial contraction (AExc), the duration of early diastolic motion (EDDur), and the relationships of EDExc with SExc, and of e`with EDExc and EDDur, are all unknown.

Methods

The study group was 22 subjects with HCM and there were 22 age and sex matched control subjects. SExc, EDExc, e`, AExc and EDDur were measured from pulsed wave tissue Doppler signals acquired from the septal and lateral walls. In the combined group of HCM and control subjects, multivariate analyses were performed to identify independent predictors of EDExc and e`for both LV walls.

Results

SExc, EDExc and e`were all lower, and EDDur was longer in the HCM group compared to the control group for both LV walls (p<0.05 for all). In contrast, AExc was lower for the septal wall in the HCM group (p<0.05), but not different between the groups for the lateral wall. In regression analyses of the combined group, EDExc was positively correlated with SExc, and SExc explained 57–86% of the variances in septal and lateral EDExc, e`was positively correlated with EDExc, and EDExc explained 58–68% of the variances of e`, whereas the combination of EDExc with EDDur explained 87–92% of the variances in e`. A diagnosis of HCM was not an independent predictor of EDExc when in combination with SExc, but was a minor contributor to the prediction of e`in combination with EDExc and EDDur.

Conclusion

In HCM, the decrease in LV longitudinal contraction is the major mechanism accounting for a lower EDExc, the lower e`is accounted for by contributions from the lower EDExc and prolongation of early diastolic motion, and there is no atrial compensation for the reduction of long-axis contraction.

The role of echocardiography for diagnosis and prognostic stratification in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most frequent cardiac disease with genetic substrate, affecting about 0.2-0.5% of the population. While most of the patients with HCM have a relatively good prognosis, some are at increased risk of adverse events. Identifying such patients at risk is important for optimal treatment and follow-up. While clinical and electrocardiographic information plays an important role, echocardiography remains the cornerstone in assessing patients with HCM. In this review, we discuss the role of echocardiography in diagnosing HCM, the key features that differentiate HCM from other diseases and the use of echocardiography for risk stratification in this setting (risk of sudden cardiac death, heart failure, atrial fibrillation and stroke). The use of modern echocardiographic techniques (deformation imaging, 3D echocardiography) refines the diagnosis and prognostic assessment of patients with HCM. The echocardiographic data need to be integrated with clinical data and other information, including cardiac magnetic resonance, especially in challenging cases or when there is incomplete information, for the optimal management of these patients.

Impact of maternal diabetes and obesity on fetal cardiac functions

Background

In several developing industrial countries, the incidence of obesity among populations is spreading quickly and dramatically; also, the frequency of maternal obesity is in continuous elevation, which represents a considerable public health problem. Maternal hyperglycemia is a common gestational risk factor for the fetus. Several studies proposed that maternal DM and obesity lead to intrauterine impacts which induce changes in the fetal myocardium, and the pre-pregnancy obesity and diabetes are accompanied with development of cardiovascular alterations in the offspring and subsequent pathological changes in their early life. The aim of this study is to assess the cardiac function in fetuses of obese pregnant women (FOW) and fetuses of diabetic women (FDW) in comparison with fetuses of normal pregnant women (FNW) using tissue Doppler imaging.

Results

There was impairment in systolic and diastolic cardiac function in both fetuses of obese and diabetic women with decreased global longitudinal strain tissue Doppler velocities at 30 weeks of gestation compared to fetuses of normal women.

Conclusion

Imaging of the fetus of pregnant women by Echo Doppler at about 30 weeks of gestations showed a reduced cardiac function of fetuses of obese and diabetic women matched with fetuses of normal BMI women. Our finding proposed that early subclinical alterations in the fetal cardiac output can arise from maternal obesity alone. This explains the predilection of children of obese mothers at advanced ages to cardiovascular disorder.

Left ventricular diastolic dysfunction in HIV-uninfected infants exposed in utero to antiretroviral therapy

OBJECTIVES

To longitudinally measure LV diastolic function in HIV-exposed but uninfected (HEU) children perinatally exposed to ART.

DESIGN

HEU children who were perinatally exposed to antiretroviral therapy (ART) may be at risk for adverse cardiac effects. We have previously reported that those children have decreased left ventricular (LV) mass, dimension, and septal thickness with increased contractility.

METHODS

Serial echocardiograms were obtained at specific times from birth to 48 months from two groups of HIV-uninfected children: 148 HIV-negative children who were perinatally exposed to ART and 130 non-ART-exposed HIV-unexposed healthy controls. The following LV diastolic indices were obtained: mitral valve early and late diastolic velocity (E and A), tissue Doppler-derived LV-free wall and septal early diastolic velocity (LV e' and sep e').

RESULTS

All echocardiographic indices were significantly different in ART-exposed children compared with ART-unexposed healthy controls. Both E and A were overall lower at all ages by 8.28 cm/s (P = 0.0002) and 13.46 cm/s (P < 0.0001) respectively. E/A ratio was higher by 0.27, 0.46, and 0.28 units at birth, 1 year and 2 years of age, respectively (all P ≤ 0.01). Moreover, LV e' and sep e' were overall lower at all ages by 0.84 cm/s (P = 0.01) and 0.47 cm/s (P = 0.02), respectively.

CONCLUSION

Children who were exposed to ART in utero have subclinical yet significant differences in specific LV diastolic indices. Follow-up with serial echocardiograms are recommended in this population to further assess the potential cardiac toxicity of perinatal exposure to ART.

Left Atrial Strain to Identify Diastolic Dysfunction in Children with Cardiomyopathies

Background: Left ventricular (LV) diastolic dysfunction (DD) carries worse prognosis in childhood. 2-dimensional (2-D) left atrial (LA) strain accurately categorizes DD in adults but its role in children is unknown. Thus, the aim of this study is to investigate whether LA strain and strain rate could diagnose and classify DD in children with dilated (CMD), hypertrophic (HCM) and restrictive (RCM) cardiomyopathies (CM). Methods and Results: The study includes 136 children (aged 8.8 ± 6 years): 44 with DCM, 40 with HCM, 7 with RCM and 45 healthy controls (CTRL). They underwent standard echocardiographic examination and 2-D speckle-tracking analyses (LV longitudinal peak systolic strain (LS), LA peak systolic strain and strain rate). No significant differences in mitral E/A and pulmonary S/D ratios were observed among the four groups. Although E/E’ and indexed left atrial volumes were found to be significantly higher in HCM, DCM and RCM compared to CTRL (p < 0.001), they showed no significant difference among the three CM groups. LV LS values were significantly reduced in CM vs CTRL (p < 0.001) and in DCM vs HCM (p < 0.01), with no other differences between the remaining groups. LA peak systolic strain and strain rate values showed a steady and significant decrease with worsening of DD. Receiver Operating Characteristics (ROC) curves showed area under the curve of 0.976 (p < 0.001) for LA strain and 0.946 (p < 0.001) for LA strain rate, to distinguish CTRL from CMs. Conclusions: LA strain and strain rate could be a promising tool to better understand and classify DD in children with cardiomyopathies, opening the way to its clinical use.

Impaired Systolic and Diastolic Left Ventricular Function in Children with Chronic Kidney Disease - Results from the 4C Study

Children with chronic kidney disease suffer from excessive cardiovascular mortality and early alterations of the cardiovascular system. Tissue doppler imaging is a validated echocardiographic tool to assess early systolic and diastolic cardiac dysfunction. We hypothesized that tissue Doppler velocities would reveal reduced cardiac function in children with chronic kidney disease compared to healthy children. A standardized echocardiographic exam was performed in 128 patients of the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) Study aged 6–17 years with an estimated glomerular filtration rate (eGFR) below 60 ml/min/1.73 m². Tissue Doppler measurements included early (E’) and late (A’) diastolic and systolic (S’) velocity at the mitral and septal annulus of the left ventricle. Measured values were normalized to z-scores using published reference data. Predictors of E’/A’, E/E’, S’ and left ventricular mass index (LVMI) were assessed by multiple linear regression analyses. Tissue Doppler E’ was reduced and tissue Doppler A’ increased, resulting in a reduced tissue Doppler E’/A’ ratio (z-score −0.14, p < 0.0001) indicating reduced diastolic function compared to healthy children. Reduced tissue Doppler E’/A’ Z-Scores were independently associated with lower eGFR (p = 0.002) and increased systolic blood pressure (p = 0.02). While E/E’ Z-Scores were increased (Z-score 0.57, p < 0.0001), patients treated with pharmacological RAS blockade but not with other antihypertensive treatments had significantly lower E/E’ and higher E’/A’ Z-Scores. Systolic tissue Doppler velocities were significantly decreased (Z-score −0.24, p = 0.001) and inversely correlated with E/E’ Z-Scores (r = −0.41, p < 0.0001). LVMI was not associated with systolic or diastolic tissue Doppler velocities. Concentric left ventricular hypertrophy showed a tendency to lower S’ in multivariate analysis (p = 0.13) but no association to diastolic function. Concentric left ventricular geometry was significantly associated with lower midwall fractional shortening. In summary, systolic and diastolic function assessed by tissue Doppler is impaired. eGFR, systolic blood pressure and the type of antihypertensive medications are significant predictors of diastolic function in children with CKD. Left ventricular morphology is largely independent of tissue Doppler velocities. Tissue Doppler velocities provide sensitive information about early left ventricular dysfunction in this population.

Serum apoptotic marker M30 is positively correlated with early diastolic dysfunction in adolescent obesity

Purpose

Obesity in adolescence has been shown to be related to cardiac geometric and functional changes. Cardiac dysfunction in adults with obesity could be attributed to chronic low-grade inflammation, apoptosis of cardiomyocyte, and glucose metabolic disorder. The aforementioned association in adolescents with obesity have never been well studied. Our aim was to determine the types of cardiac dysfunction in adolescents with obesity and survey the association between cardiac dysfunction and chronic low-grade inflammation, apoptosis, and glucose dysregulation in adolescents with obesity.

Methods

Adolescents aged between 10 and 20 years were enrolled in this study. Body mass index, waist-to-hip ratio, blood pressure, glucose metabolism, and high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor-a (TNF-α), and apoptosis marker M30 levels were measured. Echocardiographic indices were also measured. The association between serum biomarkers and echocardiographic function parameters was analyzed.

Results

Diastolic dysfunction was the major finding in the cardiac functional assessment. The main changes in glucose metabolism were elevated C-peptide level and insulin resistance. Hs-CRP, IL-6, and M30 levels also increased with adolescent obesity. M30 was the major biomarker that was highly correlated to diastolic dysfunction indices in adolescents with obesity.

Conclusions

Diastolic dysfunction was the main change in adolescent obesity. Insulin resistance, apoptotic marker M30, hs-CRP, and IL-6 were all elevated in adolescents with obesity. Only M30 was related to indices of left ventricular diastolic dysfunction among adolescents with obesity, rather than inflammation or insulin resistance.

Risk stratification in childhood hypertrophic cardiomyopathy

[first paragraph of article]The true prevalence of hypertrophic cardiomyopathy (HCM) in childhood is unknown, but population-based studies have reported an annual incidence between 0.24–0.47 per 100,000 children. The aetiology of disease is more heterogeneous than that seen in adult populations, with up to 30% of patients having an inborn error of metabolism, malformation syndrome or neuromuscular syndrome. However, as in adults, most cases are caused by mutations in the cardiac sarcomere protein genes, even in young children. The long-term outcome of childhood HCM is highly variable and has been shown to depend partly on the age of presentation and underlying aetiology. Outside of infancy, the most frequent cause of mortality is sudden cardiac death (SCD), and one of the greatest challenges in managing young patients with HCM is identifying those at greatest risk of an arrhythmic event.

Risk stratification in pediatric hypertrophic cardiomyopathy: Insights for bridging the evidence gap?

Identification of children with hypertrophic cardiomyopathy (HCM) who are at high risk for sudden cardiac death (SCD) remains challenging. Although a large number of risk factors have been implicated in HCM associated SCD, evidence for individual risk factors are not robust. Current risk prediction models are extrapolated from adult HCM and have low positive predictive value when applied to the pediatric HCM population. Clinical factors that are strongly associated with SCD in children with HCM are limited to previous adverse cardiac event, prior syncope and extreme left ventricular hypertrophy; there are variable conclusions regarding the utility of other conventional risk factors. Additionally, while implantable cardioverter defibrillators (ICDs) are effective in aborting malignant arrhythmias, ICD complication rates are higher in children than in adults. Although echocardiography derived parameters like left atrial volume, diastolic function indices, severity of left ventricular outflow tract obstruction and abnormalities in deformation imaging (strain and strain rate) have been associated with SCD risk in childhood HCM, these echocardiographic predictors have low specificity and sensitivity. More recently, cardiac magnetic resonance (CMR) imaging derived perfusion and viability (delayed gadolinium enhancement) abnormalities have been associated with SCD in childhood HCM and warrant further investigation. Given that myocyte disarray and fibrosis are prominent histological features of HCM, novel imaging modalities that allow for improved tissue characterization may provide additional insight into HCM phenotypes that are at higher risk for SCD. T₁ mapping, cardiac diffusion tensor imaging (cDTI), and assessment of a phosphocreatine/adenosine triphosphate (PCr/ATP) ratio by ³¹P magnetic resonance spectroscopy (³¹P-MRS) are future avenues of myocardial imaging that may provide additional prognostic benefit when used in conjunction with traditional assessments. Further investigations of disease pathogenesis, genotype-phenotype correlations, genetic modifiers and circulating biomarkers specific to children with HCM hold promise for a more effective and refined risk stratification model in pediatric HCM.

Intergenerational differences in the effects of transcatheter closure of atrial septal defects on cardiac function

BACKGROUND

Little is known regarding intergenerational differences in the effects of atrial sepal defect (ASD) closure on the left heart. We therefore analyzed age-related serial changes in the left heart following ASD closure.

METHODS

We studied 50 patients with an isolated ASD who underwent successful transcatheter closure using Amplatzer septal occluders (St. Jude Medical, Little Canada, MN, USA) between June 2007 and June 2013. Patients were divided into three age groups: young patients aged ≤17 years; middle-aged patients aged 18-50 years; and older patients aged >50 years. Multi-modal echocardiographic studies with different views were performed before and at 1 day, 1-3 months, and 6-12 months after ASD closure. Echocardiographic variables were compared among the groups at different time points after closure.

RESULTS

Left ventricular end-diastolic and end-systolic volume indices (EDVI and ESVI) in the older group were significantly smaller than those in the other groups before closure. EDVI and ESVI increased with time after closure in all groups with stable ejection fractions. However, EDVI and ESVI remained significantly smaller in the older group compared with the other groups. There was a significant interaction among the age groups only in terms of left atrial volume index (LAVI). LAVI increased significantly with time in the older group, but did not change in the other groups.

CONCLUSION

Although the left ventricle enlarged with time after ASD closure in all age groups, left ventricular size in older patients never reached that in younger patients. In addition to this inadequate enlargement of the left ventricle, diastolic dysfunction might also result in late left atrial enlargement in older patients following ASD closure.

Risk factors for sudden cardiac death in childhood hypertrophic cardiomyopathy: A systematic review and meta-analysis

Aims To perform a systematic literature review and meta-analysis of clinical risk factors for sudden cardiac death (SCD) in childhood hypertrophic cardiomyopathy. Methods Medline and PubMed databases were searched for original articles published in English from 1963 through to December 2015 that included patients under 18 years of age with a primary or secondary end-point of either SCD or SCD-equivalent events (aborted cardiac arrest or appropriate implantable cardioverter-defibrillator discharge) or cardiovascular death (CVD). Results Twenty-five studies (3394 patients) met the inclusion criteria. We identified four conventional major risk factors that were evaluated in at least four studies and that we found to be statistically associated with an increased risk of death in at least two studies: previous adverse cardiac event (pooled hazard ratio [HR] 5.4, 95% confidence interval [CI] 3.67-7.95, p < 0.001); non-sustained ventricular tachycardia (pooled HR 2.13, 95% CI 1.21-3.74, p = 0.009); unexplained syncope (pooled HR 1.89, 95% CI 0.69-5.16, p = 0.22); and extreme left ventricular hypertrophy (pooled HR 1.80, 95% CI 0.75-4.32, p = 0.19). Left atrial diameter did not meet the major risk factor criteria; however, this is likely to be an additional significant risk factor. 'Minor' risk factors included a family history of SCD, gender, age, symptoms, electrocardiogram changes, abnormal blood pressure response to exercise and left ventricular outflow tract obstruction. Conclusions A lack of well-designed, large, population-based studies in childhood hypertrophic cardiomyopathy means that the evidence base for individual risk factors is not robust. We have identified four clinical parameters that are likely to be associated with increased risk of SCD, SCD-equivalent events or CVD. Multi-centre prospective studies are needed in order to further determine the relevance of these factors in predicting SCD in childhood hypertrophic cardiomyopathy and to identify novel risk markers. Condensed abstract A systematic review and meta-analysis of clinical risk factors predicting sudden cardiac death in childhood hypertrophic cardiomyopathy was performed, identifying four 'major' factors: previous adverse cardiac event; non-sustained ventricular tachycardia; syncope; and extreme left ventricular hypertrophy. Well-designed multi-centre studies are required in the future in order to confirm these findings.

Impact of Pulmonary Hemodynamics and Ventricular Interdependence on Left Ventricular Diastolic Function in Children With Pulmonary Hypertension

BACKGROUND

Through ventricular interdependence, pulmonary hypertension (PH) induces left ventricular (LV) dysfunction. We hypothesized that pediatric PH patients have LV diastolic dysfunction, related to adverse pulmonary hemodynamics, leftward septal shift, and prolonged right ventricular systole.

METHODS AND RESULTS

Echocardiography was prospectively performed at 2 institutions in 54 pediatric PH patients during cardiac catheterization and in 54 matched controls. Diastolic LV measures including myocardial deformation were assessed by echocardiography. PH patients had evidence of LV diastolic dysfunction, most consistent with impaired LV relaxation, though some features of reduced ventricular compliance were present. PH patients demonstrated the following: reduced mitral E velocity and inflow duration, mitral E' and E'/A', septal E' and A', pulmonary vein S and D wave velocities, and LV basal global early diastolic circumferential strain rate and increased mitral E deceleration time, LV isovolumic relaxation time, mitral E/E', and pulmonary vein A wave duration. PH patients demonstrated leftward septal shift and prolonged right ventricular systole, both known to affect LV diastole. These changes were exacerbated in severe PH. There were no statistically significant differences in diastolic measures between patients with and without a shunt and minimal differences between patients with and without congenital heart disease. Multiple echocardiographic LV diastolic parameters demonstrated weak-to-moderate correlations with invasively determined PH severity, leftward septal shift, and prolonged right ventricular systole.

CONCLUSIONS

Pediatric PH patients exhibit LV diastolic dysfunction most consistent with impaired relaxation and reduced myocardial deformation, related to invasive hemodynamics, leftward septal shift, and prolonged right ventricular systole.

Comparison of echocardiography with tissue Doppler imaging and magnetic resonance imaging with delayed enhancement in the assessment of children with hypertrophic cardiomyopathy

INTRODUCTION

In children with hypertrophic cardiomyopathy (HCM) there often occurs a non-ischemic pattern of myocardial fibrosis, which could be the cause of impaired left ventricular (LV) diastolic function assessed by tissue Doppler imaging (TDI). The aim of the study was to determine the prevalence of myocardial fibrosis in children with HCM, and to evaluate its relationship with echocardiographic parameters including LV diastolic dysfunction.

MATERIAL AND METHODS

Sixty-three children with HCM, mean age 12.2 ±4.5 years, underwent magnetic resonance imaging (MRI) and echocardiographic study from January 2010 to April 2014. The results of MRI, echocardiography, and TDI velocities were analyzed and compared between children with and without myocardial fibrosis. Moreover, correlations between the results of echocardiography and MRI were assessed.

RESULTS

Our results showed a significant correlation between magnetic resonance and echocardiographic measurements of septal wall thickness, posterior wall thickness, LV mass and left atrial dimension. Children with myocardial fibrosis (60%) had a significantly thicker interventricular septum (21.3 vs. 1.8 mm; p < 0.0001) and larger left atrial dimension (36.7 vs. 27.8 mm; p = 0.0004) and volume index (42.0 vs. 26.6 ml/m²; p = 0.0011). Tissue Doppler imaging demonstrated significantly decreased lateral E' (9.02 vs. 13.53 cm/s; p < 0.0001) and septal E' (7.05 vs. 9.36 cm/s; p = 0.0082) velocities and a significantly increased transmitral lateral (10.34 vs. 6.68; p = 0.0091) and septal (13.1 vs. 9.8; p = 0.046) E/E' ratio in children with myocardial fibrosis.

CONCLUSIONS

Myocardial fibrosis in children with hypertrophic cardiomyopathy was associated with markers for disease severity such as larger septum thickness, enlargement of the left atrium as well as impairment of left ventricular diastolic function. Tissue Doppler imaging is a helpful tool to detect the presence of left ventricular diastolic dysfunction in children with hypertrophic cardiomyopathy and myocardial fibrosis.

Utility of Cardiovascular Magnetic Resonance-Derived Wave Intensity Analysis As a Marker of Ventricular Function in Children with Heart Failure and Normal Ejection Fraction

OBJECTIVE

This study sought to explore the diagnostic insight of cardiovascular magnetic resonance (CMR)-derived wave intensity analysis to better study systolic dysfunction in young patients with chronic diastolic dysfunction and preserved ejection fraction (EF), comparing it against other echocardiographic and CMR parameters.

BACKGROUND

Evaluating systolic and diastolic dysfunctions in children is challenging, and a gold standard method is currently lacking.

METHODS

Patients with presumed diastolic dysfunction [n = 18; nine aortic stenosis (AS), five hypertrophic, and four restrictive cardiomyopathies] were compared with age-matched control subjects (n = 18). All patients had no mitral or aortic incompetence, significant AS, or reduced systolic EF. E/A ratio, E/E' ratio, deceleration time, and isovolumetric contraction time were assessed on echocardiography, and indexed left atrial volume (LAVi), acceleration time (AT), ejection time (ET), and wave intensity analyses were calculated from CMR. The latter was performed on CMR phase-contrast flow sequences, defining a ratio of the peaks of the early systolic forward compression wave (FCW) and the end-systolic forward expansion wave (FEW).

RESULTS

Significant differences between patients and controls were seen in the E/E' ratio (8.7 ± 4.0 vs. 5.1 ± 1.3, p = 0.001) and FCW/FEW ratio (2.5 ± 1.6 vs. 7.2 ± 4.2 × 10^-5 m/s, p < 0.001), as well as-as expected-LAVi (80.7 ± 22.5 vs. 51.0 ± 10.9 mL/m², p < 0.001). In particular, patients exhibited a lower FCW (2.5 ± 1.6 vs. 7.2 ± 4.2 × 10^-5 m/s, p < 0.001) in the face of preserved EF (67 ± 11 vs. 69 ± 5%, p = 0.392), as well as longer isovolumetric contraction time (49 ± 7 vs. 34 ± 7 ms, p < 0.001) and ET/AT (0.35 ± 0.04 vs. 0.27 ± 0.04, p < 0.001).

CONCLUSION

This study shows that the wave intensity-derived ratio summarizing systolic and diastolic function could provide insight into ventricular function in children, on top of CMR and echocardiography, and it was here able to identify an element of ventricular dysfunction with preserved EF in a small group of young patients.

Echocardiographic diagnosis of the different phenotypes of hypertrophic cardiomyopathy

Hypertrophic Cardiomyopathy (HCM) is an inherited cardiovascular disorder of great genetic heterogeneity and has a prevalence of 0.1 – 0.2 % in the general population. Several hundred mutations in more than 27 genes, most of which encode sarcomeric structures, are associated with the HCM phenotype. Then, HCM is an extremely heterogeneous disease and several phenotypes have been described over the years. Originally only two phenotypes were considered, a more common, obstructive type (HOCM, 70 %) and a less common, non-obstructive type (HNCM, 30 %) (Maron BJ, et al. Am J Cardiol 48:418 –28, 1981). Wigle et al. (Circ 92:1680–92, 1995) considered three types of functional phenotypes: subaortic obstruction, midventricular obstruction and cavity obliteration. A leader american working group suggested that HCM should be defined genetically and not morphologically (Maron BJ, et al. Circ 113:1807–16, 2006). The European Society of Cardiology Working Group on Myocardial and Pericardial Diseases recommended otherwise a morphological classification (Elliott P, et al. Eur Heart J 29:270–6, 2008). Echocardiography is still the principal tool for the diagnosis, prognosis and clinical management of HCM. It is well known that the echocardiographic picture may have a clinical and prognostic impact. For this reason, in this article, we summarize the state of the art regarding the echocardiographic pattern of the HCM phenotypes and its impact on clinical course and prognosis.

Relation of Doppler Tissue Imaging Parameters With Heart Failure Progression in Hypertrophic Cardiomyopathy

Refractory progressive heart failure (HF) is becoming the predominant cause of mortality in nonobstructive hypertrophic cardiomyopathy (HC). To anticipate development of this important and often unpredictable clinical course, we investigated whether left ventricular diastolic dysfunction, assessed by echocardiographic Doppler parameters, could identify a subset of patients with HC without obstruction at rest who would experience progression of HF. Diastolic function parameters, assessed by Doppler tissue imaging (DTI), mitral inflow, and pulmonary venous flow were measured in 274 consecutive adult patients with HC evaluated from 2003 to 2007. DTI and other diastolic and clinical/demographic parameters were measured against the composite end point of HF/death, heart transplantation, or progression to advanced New York Heart Association functional class III/IV symptoms and sudden death (SD)/implantable defibrillator (ICD) interventions. HF end points were reached in 19 of 274 patients (7%) over a follow-up period of 4.0 ± 2.3 years. Variables significantly associated with HF outcome by univariate analysis included male gender, initial New York Heart Association class II, lower ejection fraction, and reduced septal and lateral e' mitral annular tissue velocities. Multivariable analysis showed only a reduced lateral e' mitral annular tissue velocity to be independently associated with the composite HF end points (HR 0.77; 95% CI 0.65 to 0.91; p = 0.003). In addition, estimated pulmonary arterial systolic pressure and extensive late gadolinium enhancement by magnetic resonance were also associated with HF outcome (p = 0.04 and p <0.001, respectively). No Doppler (or clinical) variable was associated with SD/appropriate ICD interventions. In conclusion, in HC without outflow obstruction at rest, diastolic dysfunction, evidenced by DTI-reduced lateral e' mitral annular tissue velocity, was associated with adverse long-term HF outcome but was unrelated to SD. This echocardiographic marker provides a potential noninvasive strategy for anticipating progressive HF in this HC patient group.

Tissue Doppler imaging in fetuses with aortic stenosis and evolving hypoplastic left heart syndrome before and after fetal aortic valvuloplasty

OBJECTIVES

Fetal aortic valvuloplasty can improve filling and reduce afterload of the left ventricle in critical aortic stenosis. Success of an intrauterine intervention is currently measured by technical success, clinical survival and eventual postnatal biventricular physiology. In the present study we investigated the use of tissue Doppler imaging (TDI) to evaluate changes in ventricular function assessed before and after prenatal aortic valvuloplasty.

METHODS

Between October 2008 and December 2012, cardiac function was assessed by TDI before and after intervention in 23 fetuses that underwent technically successful valvuloplasty for critical aortic stenosis and in which postnatal outcome was known. The measurements were transformed into gestational age-independent Z-scores where appropriate.

RESULTS

Mean ± SD gestational age at intervention was 27.5 ± 3.1 weeks. Of the 23 fetuses, 14 had biventricular outcome. Before intervention all left ventricular (LV) TDI-derived parameters and mitral annular plane systolic excursion (MAPSE) were severely abnormal. It was possible to demonstrate considerably improved cardiac function after technically successful valvuloplasty. Among fetuses with postnatal biventricular outcome, TDI-derived LV myocardial peak velocity during early diastole (E') and myocardial peak velocity during systole in the ejection phase (S') significantly increased, E'/myocardial peak velocity during late diastole with atrial contraction (A') increased towards normal values, and LV transmitral-to-mitral-annular diastolic velocity ratio (E/E') and myocardial performance index (MPI') decreased but remained abnormally elevated. In addition, right ventricular A', S' and MPI' significantly improved after intervention.

CONCLUSION

Technically successful fetal aortic valvuloplasty led to significantly improved myocardial performance. It was possible to use TDI to detect distinct changes in ventricular function and TDI-derived parameters correlated with a biventricular outcome after birth. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.