Natural history and outcomes in paediatric RASopathy-associated hypertrophic cardiomyopathy

AIMS

This study aimed to describe the natural history and predictors of all-cause mortality and sudden cardiac death (SCD)/equivalent events in children with a RASopathy syndrome and hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

This is a retrospective cohort study from 14 paediatric cardiology centres in the United Kingdom and Ireland. We included children <18 years with HCM and a clinical and/or genetic diagnosis of a RASopathy syndrome [Noonan syndrome (NS), NS with multiple lentigines (NSML), Costello syndrome (CS), cardiofaciocutaneous syndrome (CFCS), and NS with loose anagen hair (NS-LAH)]. One hundred forty-nine patients were recruited [111 (74.5%) NS, 12 (8.05%) NSML, 6 (4.03%) CS, 6 (4.03%) CFCS, 11 (7.4%) Noonan-like syndrome, and 3 (2%) NS-LAH]. NSML patients had higher left ventricular outflow tract (LVOT) gradient values [60 (36-80) mmHg, P = 0.004]. Over a median follow-up of 197.5 [inter-quartile range (IQR) 93.58-370] months, 23 patients (15.43%) died at a median age of 24.1 (IQR 5.6-175.9) months. Survival was 96.45% [95% confidence interval (CI) 91.69-98.51], 90.42% (95% CI 84.04-94.33), and 84.12% (95% CI 75.42-89.94) at 1, 5, and 10 years, respectively, but this varied by RASopathy syndrome. RASopathy syndrome, symptoms at baseline, congestive cardiac failure (CCF), non-sustained ventricular tachycardia (NSVT), and maximal left ventricular wall thickness were identified as predictors of all-cause mortality on univariate analysis, and CCF, NSVT, and LVOT gradient were predictors for SCD or equivalent event.

CONCLUSIONS

These findings highlight a distinct category of patients with Noonan-like syndrome with a milder HCM phenotype but significantly worse survival and identify potential predictors of adverse outcome in patients with RASopathy-related HCM.

Sudden cardiac death in childhood RASopathy-associated hypertrophic cardiomyopathy: Validation of the HCM risk-kids model and predictors of events

BACKGROUND

RASopathies account for nearly 20% of cases of childhood hypertrophic cardiomyopathy (HCM). Sudden cardiac death (SCD) occurs in patients with RASopathy-associated HCM, but the risk factors for SCD have not been systematically evaluated.

AIM

To validate the HCM Risk-Kids SCD risk prediction model in children with RASopathy-associated HCM and investigate potential specific SCD predictors in this population.

METHODS

Validation of HCM Risk-Kids was performed in a retrospective cohort of 169 patients with a RASopathy-associated HCM from 15 international paediatric cardiology centres. Multiple imputation by chained equations was used for missing values related to the HCM Risk-Kids parameters.

RESULTS

Eleven patients (6.5%) experienced a SCD or equivalent event at a median age of 12.5 months (IQR 7.7-28.64). The calculated SCD/equivalent event incidence was 0.78 (95% CI 0.43-1.41) per 100 patient years. Six patients (54.54%) with an event were in the low-risk category according to the HCM Risk-Kids model. Harrell's C index was 0.60, with a sensitivity of 9.09%, specificity of 63.92%, positive predictive value of 1.72%, and negative predictive value of 91%; with a poor distinction between the different risk groups. Unexplained syncope (HR 42.17, 95% CI 10.49-169.56, p < 0.001) and non-sustained ventricular tachycardia (HR 5.48, 95% CI 1.58-19.03, p < 0.007) were predictors of SCD on univariate analysis.

CONCLUSION

Unexplained syncope and the presence of NSVT emerge as predictors for SCD in children with RASopathy-associated HCM. The HCM Risk-Kids model may not be appropriate to use in this population, but larger multicentre collaborative studies are required to investigate this further.

Short-term outcome of late gadolinium changes detected on cardiovascular magnetic resonance imaging following coronavirus disease 2019 Pfizer/BioNTech vaccine-related myocarditis in adolescents

BACKGROUND

Rare cases of cardiac inflammation following vaccination for severe acute respiratory coronavirus 2 (SARS-CoV-2) have been reported.

OBJECTIVE

To study paediatric patients with clinical findings of acute inflammation post coronavirus disease 2019 (COVID-19) Pfizer/BioNTech vaccination using cardiovascular magnetic resonance imaging (MRI) in acute and subacute phases.

MATERIALS AND METHODS

We enrolled adolescents younger than 18 years who presented at one of two institutions between July 2021 and August 2022 with clinical and laboratory findings of acute myocarditis shortly following COVID-19 Pfizer/BioNTech vaccination. They all underwent cardiovascular MRI using the institutional myocarditis protocol.

RESULTS

Five adolescents (four boys) underwent eight scans between 3 days and 109 days (mean 49 days) after the onset of symptoms following COVID-19 vaccination. Myocardial oedema appeared on short tau inversion recovery (STIR) T2-weighted images in three adolescents at presentation (3-12 days after symptom onset). In these children, the myocardial oedema/acute inflammation had resolved at follow-up cardiovascular MRI (53-68 days after first MRI). However, in all three adolescents, a persistent area of late gadolinium enhancement was evident at follow-up, suggesting post-myocarditic fibrosis. One adolescent scanned only once, 66 days after being symptomatic, had no acute inflammation but persistent fibrotic changes. This last adolescent, who underwent the first scan 109 days after symptom onset, had findings compatible with an episode of previous myocarditis, with mild ongoing regional myocardial oedema/inflammation.

CONCLUSION

This study on post-vaccine myocarditis demonstrates residual lesions with persistent areas of late gadolinium enhancement/myocardial fibrosis with ongoing myocardial oedema after resolution of the initial myocardial oedema a few weeks after Pfizer/BioNTech vaccination. There is an urgent need to recognise and fully investigate the outcome of post-vaccination myocarditis.

Pediatric Cardiac Magnetic Resonance Reference Values for Biventricular Volumes Derived From Different Contouring Techniques

BACKGROUND

Measurement of ventricular volumes and function using MRI is an important tool in pediatric congenital heart disease. However, normal values for children are sparce and analysis methods are inconsistent.

PURPOSE

To propose biventricular reference values in children for two MRI postprocessing (contouring) techniques.

STUDY TYPE

Retrospective.

SUBJECTS

A total of 154 children from two institutions (13.9 ± 2.8 years; 101 male) that were referred for a clinical MRI study.

FIELD STRENGTH/SEQUENCE

1.5 T; balanced steady-state free precession (bSSFP) sequence.

ASSESSMENT

Left ventricular (LV) and right ventricular (RV) end-diastolic and end-systolic volumes (LVEDV, LVESV, RVEDV, RVESV) and end-diastolic and end-systolic myocardial mass (LVEDMM, LVESMM, RVEDMM, RVESMM) were measured from short-axis images using two contouring techniques: 1) papillary muscles, trabeculations and the moderator band were included in the ventricular blood volume and excluded from the myocardial mass, 2) papillary muscles, trabeculations and the moderator band were excluded from the ventricular volume and included in the ventricular mass.

STATISTICAL TESTS

Univariable and multivariable linear regression models were used to evaluate relationships between sex, weight, height, body surface area (BSA) and age and volumetric results. Reference graphs and tables were created with the LMS-method. Contouring techniques were compared by intraclass correlation, regression analysis and Bland-Altman plots. A P value < 0.05 was considered statistically significant.

RESULTS

Height and BSA were significantly associated with LVESV (method 1) and with LVEDV and RVEDV (method 2). LVESV (method 2), RVESV (both methods), RVEDV (method 1), and LVEDMM and RVEDMM (both methods), showed significant associations with height and weight. LVSV and RVSV (both methods) were significantly associated with BSA and weight. RVESV (method 1) was significantly associated with age. Gender showed significant associations for all parameters.

DATA CONCLUSION

The proposed pediatric reference values can be used in the diagnosis and follow-up of congenital or acquired heart disease and for research purposes.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Reference Values for Pediatric Atrial Volumes Assessed by Steady-State Free-Precession Magnetic Resonance Imaging Using Monoplane and Biplane Area-Length Methods

BACKGROUND

Measurement of atrial volumes by MRI is becoming increasingly important in pediatric cardiac disorders. However, MRI normal values for atrial volumes in children are lacking.

PURPOSE

To establish pediatric reference values for atrial volumes.

STUDY TYPE

Retrospective.

SUBJECTS

A total of 155 healthy children from two large institutions (103 male, age 13.9 ± 2.8 years, range 4-18 years).

FIELD STRENGTH/SEQUENCE

A 1.5 T; balanced steady-state free precession (bSSFP) sequence.

ASSESSMENT

The monoplane and biplane area-length methods were used to measure minimal and maximal left and right atrial volumes (LAmin , LAmax , RAmin , and RAmax ) from four-chamber (4ch) and two-chamber (2ch) MR cine images. Centile charts and tables for atrial volumes were created.

STATISTICAL TESTS

Descriptive statistics, lambda-mu-sigma (LMS)-method of Cole and Green, univariable and multivariable linear regression models. A P value < 0.05 was considered to be statistically significant.

RESULTS

In the multivariable linear model, body surface area was significantly associated with all atrial volumes and sex was significantly associated with RA volumes, LA volumes measured in the 2ch-view as well as biplane LAmax. Average atrial volumes measured: monoplane 4ch: LAmin 13.1 ± 4.8 mL/m2 , LAmax 33.4 ± 8.8 mL/m2 , RAmin 18.5 ± 6.8 mL/m2 , RAmax 33.2 ± 9.6 mL/m2 ; monoplane 2ch: LAmin 12.7 ± 4.9 mL/m2 , LAmax 30.5 ± 9.5 mL/m2 ; biplane: LAmin 12.3 ± 4.5 mL/m2 , LAmax 30.9 ± 8.7 mL/m2 .

DATA CONCLUSION

Pediatric MRI reference values for atrial volumes have been provided.

TECHNICAL EFFICACY

2 EVIDENCE LEVEL: 4.

Myocardial Deformation in the Pediatric Age Group: Normal Values for Strain and Strain Rate Using 2D Magnetic Resonance Feature Tracking

BACKGROUND

Myocardial deformation can be assessed from routine cardiac magnetic resonance (MR) images using two-dimensional feature tracking (2D-FT). Although reference values are essential for implementation of strain imaging in clinical practice, data for the healthy pediatric age group are limited.

PURPOSE

To provide pediatric MR reference values for strain and strain rate for all four heart chambers.

STUDY TYPE

Retrospective.

SUBJECTS

One hundred and fifty-seven healthy children from two institutions (102 male, age 4.7-18 years).

FIELD STRENGTH/SEQUENCE

1.5 T; balanced steady-state free precession sequence.

ASSESSMENT

Left ventricular (LV) global and regional longitudinal, circumferential, and radial strain and strain rate as well as right ventricular (RV) and atrial global and regional longitudinal strain and strain rate were measured in two-, three-, and four-chamber views and the short axis stack. The relationships between strain parameters and age, height, weight, and gender were investigated. Age- and height-specific centile curves and tables were created for LV strain and strain rate. For all other global strain parameters, the mean was calculated as a reference.

STATISTICAL TESTS

Lambda-mu-sigma (LMS)-method of Cole and Green, univariable, and multivariable linear regression models. A P value <0.05 was considered to be statistically significant.

RESULTS

Age, height and weight had a significant influence on LV global strain values. These parameters also showed an influence on RV strain but only in boys (girls P = 0.12) and none of the variables had a significant influence on atrial strain (P = 0.19-0.49). Gender differences were only found for RV strain values.

DATA CONCLUSION

Pediatric potential reference values for myocardial deformation parameters of both ventricles and atria are provided. The values may serve as a reference in future studies and clinical practice.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 5.

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.

Clinical outcomes and programming strategies of implantable cardioverter-defibrillator devices in paediatric hypertrophic cardiomyopathy: a UK National Cohort Study

AIMS

Sudden cardiac death (SCD) is the most common mode of death in paediatric hypertrophic cardiomyopathy (HCM). This study describes the implant and programming strategies with clinical outcomes following implantable cardioverter-defibrillator (ICD) insertion in a well-characterized national paediatric HCM cohort.

METHODS AND RESULTS

Data from 90 patients undergoing ICD insertion at a median age 13 (±3.5) for primary (n = 67, 74%) or secondary prevention (n = 23, 26%) were collected from a retrospective, longitudinal multi-centre cohort of children (<16 years) with HCM from the UK. Seventy-six (84%) had an endovascular system [14 (18%) dual coil], 3 (3%) epicardial, and 11 (12%) subcutaneous system. Defibrillation threshold (DFT) testing was performed at implant in 68 (76%). Inadequate DFT in four led to implant adjustment in three patients. Over a median follow-up of 54 months (interquartile range 28-111), 25 (28%) patients had 53 appropriate therapies [ICD shock n = 45, anti-tachycardia pacing (ATP) n = 8], incidence rate 4.7 per 100 patient years (95% CI 2.9-7.6). Eight inappropriate therapies occurred in 7 (8%) patients (ICD shock n = 4, ATP n = 4), incidence rate 1.1/100 patient years (95% CI 0.4-2.5). Three patients (3%) died following arrhythmic events, despite a functioning device. Other device complications were seen in 28 patients (31%), including lead-related complications (n = 15) and infection (n = 10). No clinical, device, or programming characteristics predicted time to inappropriate therapy or lead complication.

CONCLUSION

In a large national cohort of paediatric HCM patients with an ICD, device and programming strategies varied widely. No particular strategy was associated with inappropriate therapies, missed/delayed therapies, or lead complications.

Left ventricular noncompaction in pediatric population: could cardiovascular magnetic resonance derived fractal analysis aid diagnosis?

BACKGROUND

Cardiovascular magnetic resonance (CMR) derived fractal analysis of the left ventricle (LV) has been shown in adults to be a useful quantitative measure of trabeculation with high reproducibility and accuracy for the diagnosis of LV non-compaction (LVNC). The aim of this study was to investigate the utility and feasibility of fractal analysis in children.

METHODS

Eighty-four subjects underwent CMR: (1) 28 patients with LVNC (as defined by the Petersen criteria with NC/C ratio [Formula: see text] 2.3); (2) 28 patients referred by clinicians for assessment of hyper-trabeculation and found not to qualify as LVNC (NC/C [Formula: see text] 1.8 and < 2.3); (3) 28 controls. The fractal scores for each group were presented as global and maximal fractal dimension as well as for 3 segments of the LV: basal, mid, and apical. Statistical comparison of the fractal scores between the 3 groups was performed.

RESULTS

Global fractal dimension (FD) was higher in the LVNC group than in the hyper-trabeculated group: 1.345 (SEM 0.053) vs 1.252 (SEM 0.034), p < 0.001 and higher in hyper-trabeculated group than in controls: 1.252 (SEM 0.034) vs 1.158 (SEM 0.038), p < 0.001. The highest maximum FD was in the apical portion of the LV in the LVNC group, (1.467; SEM 0.035) whereas it was in the mid ventricle in the hyper-trabeculated (1.327; SEM 0.025) and healthy groups (1.251; SEM 0.042). Fractal analysis showed lower intra- and interobserver variability than the Petersen and Jacquier methods.

CONCLUSIONS

It is technically feasible to perform fractal analysis in children using CMR and that it is quick, accurate and reproducible. Fractal scoring accurately distinguishes between LVNC, hyper-trabeculation and healthy controls as defined by the Petersen criteria.

The role of the electrocardiographic phenotype in risk stratification for sudden cardiac death in childhood hypertrophic cardiomyopathy

AIMS

The 12-lead electrocardiogram (ECG) is routinely performed in children with hypertrophic cardiomyopathy (HCM). An ECG risk score has been suggested as a useful tool for risk stratification, but this has not been independently validated. This aim of this study was to describe the ECG phenotype of childhood HCM in a large, international, multi-centre cohort and investigate its role in risk prediction for arrhythmic events.

METHODS AND RESULTS

Data from 356 childhood HCM patients with a mean age of 10.1 years (±4.5) were collected from a retrospective, multi-centre international cohort. Three hundred and forty-seven (97.5%) patients had ECG abnormalities at baseline, most commonly repolarization abnormalities (n = 277, 77.8%); left ventricular hypertrophy (n = 240, 67.7%); abnormal QRS axis (n = 126, 35.4%); or QT prolongation (n = 131, 36.8%). Over a median follow-up of 3.9 years (interquartile range 2.0-7.7), 25 (7%) had an arrhythmic event, with an overall annual event rate of 1.38 (95% CI 0.93-2.04). No ECG variables were associated with 5-year arrhythmic event on univariable or multivariable analysis. The ECG risk score threshold of >5 had modest discriminatory ability [C-index 0.60 (95% CI 0.484-0.715)], with corresponding negative and positive predictive values of 96.7% and 6.7.

CONCLUSION

In a large, international, multi-centre cohort of childhood HCM, ECG abnormalities were common and varied. No ECG characteristic, either in isolation or combined in the previously described ECG risk score, was associated with 5-year sudden cardiac death risk. This suggests that the role of baseline ECG phenotype in improving risk stratification in childhood HCM is limited.

Cardiovascular magnetic resonance normal values in children for biventricular wall thickness and mass

BACKGROUND

Pediatric patients are becoming increasingly referred for cardiovascular magnetic resonance (CMR). Measurement of ventricular wall thickness is typically part of the assessment and can be of diagnostic importance, e.g. in arterial hypertension. However, normal values for left ventricular (LV) and right ventricular (RV) wall thickness in pediatric patients are lacking. The aim of this study was to establish pediatric centile charts for segmental LV and RV myocardial thickness in a retrospective multicenter CMR study.

METHODS

CMR was performed in 161 healthy children and adolescents with an age range between 6 and 18 years from two centers in the UK and Germany as well as from a previously published CMR project of the German Competence Network for Congenital Heart Defects. LV myocardial thickness of 16 segments was measured on the short axis stack using the American Heart Association segmentation model. In addition, the thickness of the RV inferior and anterior free wall as well as biventricular mass was measured.

RESULTS

The mean age (standard deviation) of the subjects was 13.6 (2.9) years, 64 (39.7%) were female. Myocardial thickness of the basal septum (basal antero- and inferoseptal wall) was 5.2 (1.1) mm, and the basal lateral wall (basal antero- and inferolateral) measured 5.1 (1.2) mm. Mid-ventricular septum (antero- and inferoseptal wall) measured 5.5 (1.2) mm, and mid-ventricular lateral wall (antero- and inferolateral wall) was 4.7 (1.2) mm. Separate centile charts for boys and girls for all myocardial segments and myocardial mass were created because gender was significantly correlated with LV myocardial thickness (p < 0.001 at basal level, p = 0.001 at midventricular level and p = 0.005 at the apex) and biventricular mass (LV, p < 0.001; RV, p < 0.001).

CONCLUSION

We established CMR normal values of segmental myocardial thickness and biventricular mass in children and adolescents. Our data are of use for the detection of abnormal myocardial properties and can serve as a reference in future studies and clinical practice.

A validation study of the European Society of Cardiology guidelines for risk stratification of sudden cardiac death in childhood hypertrophic cardiomyopathy

AIMS

Sudden cardiac death (SCD) is the most common cause of death in children with hypertrophic cardiomyopathy (HCM). The European Society of Cardiology (ESC) recommends consideration of an implantable cardioverter-defibrillator (ICD) if two or more clinical risk factors (RFs) are present, but this approach to risk stratification has not been formally validated.

METHODS AND RESULTS

Four hundred and eleven paediatric HCM patients were assessed for four clinical RFs in accordance with current ESC recommendations: severe left ventricular hypertrophy, unexplained syncope, non-sustained ventricular tachycardia, and family history of SCD. The primary endpoint was a composite outcome of SCD or an equivalent event (aborted cardiac arrest, appropriate ICD therapy, or sustained ventricular tachycardia), defined as a major arrhythmic cardiac event (MACE). Over a follow-up period of 2890 patient years (median 5.5 years), MACE occurred in 21 patients (7.5%) with 0 RFs, 19 (16.8%) with 1 RFs, and 3 (18.8%) with 2 or more RFs. Corresponding incidence rates were 1.13 [95% confidence interval (CI) 0.7-1.73], 2.07 (95% CI 1.25-3.23), and 2.52 (95% CI 0.53-7.35) per 100 patient years at risk. Patients with two or more RFs did not have a higher incidence of MACE (log-rank test P = 0.34), with a positive and negative predictive value of 19% and 90%, respectively. The C-statistic was 0.62 (95% CI 0.52-0.72) at 5 years.

CONCLUSIONS

The incidence of MACE is higher for patients with increasing numbers of clinical RFs. However, the current ESC guidelines have a low ability to discriminate between high- and low-risk individuals.

Clinical presentation and survival of childhood hypertrophic cardiomyopathy: a retrospective study in United Kingdom

Aims

Understanding the spectrum of disease, symptom burden and natural history are essential for the management of children with hypertrophic cardiomyopathy (HCM). The effect of changing screening practices over time has not previously been studied. This study describes the clinical characteristics and outcomes of childhood HCM over four decades in a well-characterized United Kingdom cohort.

Methods and results

Six hundred and eighty-seven patients with HCM presented at a median age of 5.2 years (range 0–16). Aetiology was: non-syndromic (n = 433, 63%), RASopathy (n = 126, 18.3%), Friedreich’s ataxia (n = 59, 8.6%) or inborn errors of metabolism (IEM) (n = 64, 9%). In infants (n = 159, 23%) underlying aetiology was more commonly a RASopathy (42% vs. 11.2%, P < 0.0001) or IEM (18.9% vs. 6.4% P < 0.0001). In those with familial disease, median age of presentation was higher (11 years vs. 6 years, P < 0.0001), 141 (58%) presented <12 years. Freedom from death or transplantation was 90.6% (87.9–92.7%) at 5 years (1.5 per 100 patient years) with no era effect. Mortality was most frequently sudden cardiac death (SCD) (n = 20, 2.9%). Children diagnosed during infancy or with an IEM had a worse prognosis (5-year survival 80.5% or 66.4%). Arrhythmic events occurred at a rate of 1.2 per 100 patient years and were more likely in non-syndromic patients (n = 51, 88%).

Conclusion

This national study describes a heterogeneous disease whose outcomes depend on the age of presentation and aetiology. Overall mortality and SCD rates have not changed over time, but they remain higher than in adults with HCM, with events occurring in syndromic and non-syndromic patients.

A Novel Quantitative Approach to Staging and Assessing Recovery from Type 1 Diabetes Mellitus: The Type 1 Diabetes Mellitus Metabolic Recovery Index

Discovery of insulin in 1921 changed the lives of patients with type 1 diabetes (T1DM) forever. What had been a death sentence became a manageable, albeit chronic, disease. Insulin did not cure the disease, as it did not address the actual disease process, but instead treated its sequelae, namely elevated blood sugars. Importantly, insulin administration fails to ensure normoglycaemia. Even with the most sophisticated ‘near closed-loop’ methods, glucose homeostasis is not restored to normal. T1DM patients face complications, both short-term, such as hypo- and hyperglycaemia, and long-term, with increased glycosylation of proteins leading to eye, kidney, nervous system and other sequelae. These complications are associated with significant morbidity and mortality even after intensive insulin treatment. Nearly 100 years after the discovery of insulin, we continue to face the challenge of addressing the disease process itself, in order to fundamentally improve the life of these patients. There are major efforts to achieve just that: to completely arrest the autoimmune process destroying the insulin-producing cells in the pancreas, or at least significantly slow the process to blunt and delay short- and long-term complications. The aim of this Communication is to propose a novel assessment tool that would serve as a quantitative outcome measure by which therapies, short of clinical cure, may be compared and their true benefit to the treatment of diabetes assessed.

The Ozaki Procedure With CardioCel Patch for Children and Young Adults With Aortic Valve Disease: Preliminary Experience – a Word of Caution

Background:

The Ozaki procedure is a surgical technique for patients with significant aortic stenosis or regurgitation or both where valve repair cannot be performed. Individual cusps are cut from glutaraldehyde-treated autologous pericardium or bovine pericardium and implanted into the aortic valve position. Encouraging results have been reported within the adult population. There are limited published data on success of this procedure in younger patients.

Methods:

We present a series of five children and young adults who underwent the Ozaki procedure with neoaortic valve cusps made from CardioCel, a decellularized bovine pericardial patch treated with a monomeric glutaraldehyde.

Results:

There were no complications in the initial postoperative period and short inpatient stay. At a mean follow-up of 29.6 months (range: 22-36 months), 4 patients had no evidence of stenosis and 3 patients had trivial or no regurgitation from the neoaortic valve. Overall, two patients had complications related to the valve and underwent reintervention during the follow-up period with a Ross procedure. One of these patients who was not taking long-term anticoagulation experienced a transient ischemic attack.

Conclusions:

Our experience demonstrates that the Ozaki procedure with CardioCel in pediatric and young adult patients should be approached with caution. Further research with larger groups of pediatric patients, comparison of different graft materials, and longer follow-up is required to ascertain long-term success in children.

Long-Term Outcomes of Childhood Left Ventricular Noncompaction Cardiomyopathy: Results From a National Population-Based Study

BACKGROUND

Long-term outcomes for childhood left ventricular noncompaction (LVNC) are uncertain. We examined late outcomes for children with LVNC enrolled in a national population-based study.

METHODS

The National Australian Childhood Cardiomyopathy Study includes all children in Australia with primary cardiomyopathy diagnosed before 10 years of age between 1987 and 1996. Outcomes for subjects with LVNC with a dilated phenotype (LVNC-D) were compared with outcomes for those with dilated cardiomyopathy. Propensity-score analysis was used for risk factor adjustment.

RESULTS

There were 29 subjects with LVNC (9.2% of all cardiomyopathy subjects), with a mean annual incidence of newly diagnosed cases of 0.11 per 100 000 at-risk individuals. Congestive heart failure was the initial symptom in 24 of 29 subjects (83%), and 27 (93%) had LVNC-D. The median age at diagnosis was 0.3 (interquartile interval, 0.08-1.3) years. The median duration of follow-up was 6.8 (interquartile interval, 0.7-24.0) years for all subjects and 24.7 (interquartile interval, 23.3 - 27.7) years for surviving subjects. Freedom from death or transplantation was 48% (95% confidence interval [CI], 30-65) at 10 years after diagnosis and 45% (95% CI, 27-63) at 15 years. In competing-risk analysis, 21% of subjects with LVNC were alive with normal left ventricular systolic function, and 31% were alive with abnormal function at 15 years. Propensity-score matching between subjects with LVNC-D and those with dilated cardiomyopathy suggested a lower freedom from death/transplantation at 15 years after diagnosis in the subjects with LVNC-D (LVNC-D, 46% [95% CI, 26-66] versus dilated cardiomyopathy, 70% [95% CI, 42-97]; P=0.08). Using propensity-score inverse probability of treatment-weighted Cox regression, we found evidence that LVNC-D was associated with a greater risk of death or transplantation (hazard ratio, 2.3; 95% CI, 1.4-3.8; P=0.0012).

CONCLUSIONS

Symptomatic children with LVNC usually present in early infancy with a predominant dilated phenotype. Long-term outcomes are worse than for matched children with dilated cardiomyopathy.

Development of a Novel Risk Prediction Model for Sudden Cardiac Death in Childhood Hypertrophic Cardiomyopathy (HCM Risk-Kids)

Importance

Sudden cardiac death (SCD) is the most common mode of death in childhood hypertrophic cardiomyopathy (HCM), but there is no validated algorithm to identify those at highest risk.

Objective

To develop and validate an SCD risk prediction model that provides individualized risk estimates.

Design, Setting, and Participants

A prognostic model was developed from a retrospective, multicenter, longitudinal cohort study of 1024 consecutively evaluated patients aged 16 years or younger with HCM. The study was conducted from January 1, 1970, to December 31, 2017.

Exposures

The model was developed using preselected predictor variables (unexplained syncope, maximal left-ventricular wall thickness, left atrial diameter, left-ventricular outflow tract gradient, and nonsustained ventricular tachycardia) identified from the literature and internally validated using bootstrapping.

Main Outcomes and Measures

A composite outcome of SCD or an equivalent event (aborted cardiac arrest, appropriate implantable cardioverter defibrillator therapy, or sustained ventricular tachycardia associated with hemodynamic compromise).

Results

Of the 1024 patients included in the study, 699 were boys (68.3%); mean (interquartile range [IQR]) age was 11 (7-14) years. Over a median follow-up of 5.3 years (IQR, 2.6-8.3; total patient years, 5984), 89 patients (8.7%) died suddenly or had an equivalent event (annual event rate, 1.49; 95% CI, 1.15-1.92). The pediatric model was developed using preselected variables to predict the risk of SCD. The model's ability to predict risk at 5 years was validated; the C statistic was 0.69 (95% CI, 0.66-0.72), and the calibration slope was 0.98 (95% CI, 0.59-1.38). For every 10 implantable cardioverter defibrillators implanted in patients with 6% or more of a 5-year SCD risk, 1 patient may potentially be saved from SCD at 5 years.

Conclusions and Relevance

This new, validated risk stratification model for SCD in childhood HCM may provide individualized estimates of risk at 5 years using readily obtained clinical risk factors. External validation studies are required to demonstrate the accuracy of this model's predictions in diverse patient populations.

Out-of-hospital cardiac arrest and survival in a patient with Noonan syndrome and multiple lentigines: a case report

Background

A 9-year-old Arabic boy attending middle school presented with an out-of-hospital cardiac arrest due to ventricular fibrillation recorded by Holter electrocardiographic monitoring. He had a background history of Noonan syndrome with multiple lentigines (also known as LEOPARD syndrome), a rare condition of autosomal dominant inheritance with approximately 200 cases reported worldwide.

Case presentation

Apart from characteristic features, the boy was known to have asymmetric septal hypertrophy with a maximum wall thickness of 24 mm measured by cardiovascular magnetic resonance imaging. A day prior to the event, he attended cardiology follow-up at our institution, and Holter monitoring was commenced. Following cardiopulmonary resuscitation by bystanders and paramedics, he reverted back into sinus rhythm after a total downtime of 24 min. He was initially treated in the intensive care unit and underwent implantable cardioverter defibrillator implantation. He has made a full recovery and remains at the top of his class.

Conclusion

This case demonstrates that sudden cardiac arrest in patients with secondary forms of hypertrophic cardiomyopathy is not necessarily protected by apparently favorable phenotypes and that events may be preceded by non-sustained ventricular tachycardia observed by Holter monitoring. Implantable cardioverter defibrillator implantation plays a critical role in both primary and secondary prevention in patients at high risk of out-of-hospital cardiac arrest.

Long-Term Outcomes of Hypertrophic Cardiomyopathy Diagnosed During Childhood: Results From a National Population-Based Study

BACKGROUND

Late survival and symptomatic status of children with hypertrophic cardiomyopathy have not been well defined. We examined long-term outcomes for pediatric hypertrophic cardiomyopathy.

METHODS

The National Australian Childhood Cardiomyopathy Study is a longitudinal population-based cohort study of children (0-10 years of age) diagnosed with cardiomyopathy between 1987 and 1996. The primary study end point was time to death or cardiac transplantation.

RESULTS

There were 80 patients with hypertrophic cardiomyopathy, with a median age at diagnosis of 0.48 (interquartile range, 0.1, 2.5) years. Freedom from death/transplantation was 86% (95% confidence interval [CI], 77.0-92.0) 1 year after presentation, 80% (95% CI, 69.0-87.0) at 10 years, and 78% (95% CI, 67.0-86.0) at 20 years. From multivariable analyses, risk factors for death/transplantation included symmetrical left ventricular hypertrophy at the time of diagnosis (hazard ratio, 4.20; 95% CI, 1.60-11.05; P=0.004), Noonan syndrome (hazard ratio, 2.88; 95% CI, 1.02-8.08; P=0.045), higher posterior wall thickness z score (hazard ratio, 1.45; 95% CI, 1.22-1.73; P<0.001), and lower fractional shortening z score (hazard ratio, 0.84; 95% CI, 0.74-0.95; P=0.005) during follow-up. Nineteen (23%) subjects underwent left ventricular myectomy. At a median of 15.7 years of follow-up, 27 (42%) of 63 survivors were treated with β-blocker, and 13 (21%) had an implantable cardioverter-defibrillator.

CONCLUSIONS

The highest risk of death or transplantation for children with hypertrophic cardiomyopathy is within 1 year after diagnosis, with low attrition rates thereafter. Many subjects receive medical, surgical, or device therapy.

Hypoxic Challenge Testing (Fitness to Fly) in children with complex congenital heart disease

Objective

Commercial airplanes fly with an equivalent cabin fraction of inspired oxygen of 0.15, leading to reduced oxygen saturation (SpO2) in passengers. How this affects children with complex congenital heart disease (CHD) is unknown. We conducted Hypoxic Challenge Testing (HCT) to assess need for inflight supplemental oxygen.

Methods

Children aged <16 years had a standard HCT. They were grouped as (A) normal versus abnormal baseline SpO2 (≥95% vs <95%) and (B) absence versus presence of an actual/potential right-to-left (R–L) shunt. We measured SpO2, heart rate, QT interval corrected for heart rate and partial pressure of carbon dioxide measured transcutaneously (PtcCO2). A test failed when children with (1) normal baseline SpO2 desaturated to 85%, (2) baseline SpO285%–94% desaturated by 15% of baseline; and (3) baseline SpO275%–84% desaturated to 70%.

Results

There were 68 children, mean age 3.3 years (range 10 weeks–14.5 years). Children with normal (n=36) baseline SpO2 desaturated from median 99% to 91%, P<0.0001, and 3/36 (8%) failed the test. Those with abnormal baseline SpO2 (n=32) desaturated from median 84% to 76%, P<0.0001, and 5/32 (16%) failed (no significant difference between groups). Children with no R–L shunt (n=25) desaturated from median 99% to 93%, P<0.0001, but 0/25 failed. Those with an actual/potential R–L shunt (n=43) desaturated from median 87% to 78%, P<0.0001, and 8/43 (19%) failed (difference between groups P<0.02). PtcCO2, heart rate and QT interval corrected for heart rate were unaffected by the hypoxic state.

Conclusions

This is the first evidence to help guide which children with CHD need a preflight HCT. We suggest all children with an actual or potential R–L shunt should be tested.

Ivabradine in Children With Dilated Cardiomyopathy and Symptomatic Chronic Heart Failure

BACKGROUND

Heart rate reduction as a therapeutic target has been investigated in adults with heart failure (HF). Ivabradine has shown promising efficacy, but has not been evaluated in children. Currently, treatment recommendations for chronic pediatric HF are based mainly on chronic HF guidelines for adults.

OBJECTIVES

The authors explored the dose-response relationship of ivabradine in children with dilated cardiomyopathy and symptomatic chronic HF. The primary endpoint was ≥20% reduction in heart rate from baseline without inducing bradycardia or symptoms.

METHODS

This was a randomized, double-blind, placebo-controlled, phase II/III study with 12 months of follow-up. Children (n = 116) receiving stable HF therapy were randomized to either ivabradine or placebo. After an initial titration period, the dose was adjusted to attain the primary endpoint. Left ventricular function (echocardiography), clinical status (New York Heart Association functional class or Ross class), N-terminal pro-B-type natriuretic peptide, and quality of life (QOL) were assessed.

RESULTS

The primary endpoint was reached by 51 of 73 children taking ivabradine (70%) versus 5 of 41 taking placebo (12%) at varying doses (odds ratio: 17.24; p < 0.0001). Between baseline and 12 months, there was a greater increase in left ventricular ejection fraction in patients taking ivabradine than placebo (13.5% vs. 6.9%; p = 0.024). New York Heart Association functional class or Ross class improved more with ivabradine at 12 months than placebo (38% vs. 25%; p = 0.24). There was a trend toward improvement in QOL for ivabradine versus placebo (p = 0.053). N-terminal pro-B-type natriuretic peptide levels decreased similarly in both groups. Adverse events were reported at similar frequencies for ivabradine and placebo.

CONCLUSIONS

Ivabradine safely reduced the resting heart rate of children with chronic HF and dilated cardiomyopathy. Ivabradine's effect on heart rate was variable, highlighting the importance of dose titration. Ivabradine treatment improved left ventricular ejection fraction, and clinical status and QOL showed favorable trends. (Determination of the efficacious and safe dose of ivabradine in paediatric patients with dilated cardiomyopathy and symptomatic chronic heart failure from ages 6 months to 18 years; ISRCTN60567801).

Distinct genetic architectures for syndromic and nonsyndromic congenital heart defects identified by exome sequencing

Congenital heart defects (CHDs) have a neonatal incidence of 0.8-1% (refs. 1,2). Despite abundant examples of monogenic CHD in humans and mice, CHD has a low absolute sibling recurrence risk (∼2.7%), suggesting a considerable role for de novo mutations (DNMs) and/or incomplete penetrance. De novo protein-truncating variants (PTVs) have been shown to be enriched among the 10% of 'syndromic' patients with extra-cardiac manifestations. We exome sequenced 1,891 probands, including both syndromic CHD (S-CHD, n = 610) and nonsyndromic CHD (NS-CHD, n = 1,281). In S-CHD, we confirmed a significant enrichment of de novo PTVs but not inherited PTVs in known CHD-associated genes, consistent with recent findings. Conversely, in NS-CHD we observed significant enrichment of PTVs inherited from unaffected parents in CHD-associated genes. We identified three genome-wide significant S-CHD disorders caused by DNMs in CHD4, CDK13 and PRKD1. Our study finds evidence for distinct genetic architectures underlying the low sibling recurrence risk in S-CHD and NS-CHD.

Uncommon variants of the scimitar syndrome in two siblings

The Scimitar syndrome is a complex association of cardiovascular and bronchopulmonary abnormalities, with the main feature a partial or total anomalous right pulmonary venous drainage to the inferior vena cava. A number of cases that lack of all the features of the typical syndrome have been described as Scimitar variant, but the incidence is rare. Familial occurrence is exceptional and limited to few cases in literature. We report two sibling diagnosed with an uncommon variant of the Scimitar syndrome.

Total anomalous pulmonary venous connection: impact of prenatal diagnosis

OBJECTIVES

To investigate whether prenatal screening is effective in the detection of total anomalous pulmonary venous connection (TAPVC) and to identify common prenatal features.

METHODS

This was a retrospective collaborative study involving 19 pediatric cardiac centers in the UK, Ireland and Sweden. Cases with TAPVC born between January 1, 1998 and December 31, 2004, and prenatally diagnosed cases whose estimated dates of delivery were within this time frame, were identified. Cases with functionally univentricular circulation or atrial isomerism were excluded. All available data and stored images were reviewed.

RESULTS

Four-hundred and twenty-four cases with TAPVC were identified prenatally or postnatally, of whom eight (1.9%) had a prenatal diagnosis of TAPVC. Median gestational age at fetal diagnosis was 26 + 6 (range, 22 + 4 to 32 + 0) weeks. Six further fetuses with TAPVC had an abnormality diagnosed on prenatal ultrasound, but not the TAPVC. This included other congenital heart defects (four cases) and isolated pleural effusion (two cases). Seventeen (4.0%) of the 422 liveborn infants had a first-degree relative with congenital heart disease; and six of 17 had a sibling with TAPVC. Two died in utero. Of the liveborn infants diagnosed prenatally with TAPVC, none required urgent intervention for pulmonary venous obstruction and all were alive and well at a median of 2.3 (range, 1.0-7.0) years after surgical repair.

CONCLUSION

Prenatal diagnosis of TAPVC is infrequent using current screening methods. Where there is a family history of TAPVC, specialized fetal echocardiography at 20 and 28 weeks' gestation may be indicated.

Clinical features and outcomes of childhood dilated cardiomyopathy: results from a national population-based study

BACKGROUND

Despite considerable mortality, population-based prognostic factors for childhood dilated cardiomyopathy are lacking.

METHODS AND RESULTS

A population-based cohort study was undertaken of all children in Australia who presented with cardiomyopathy at age 0 to 10 years between January 1, 1987, and December 31, 1996. A single cardiologist analyzed all cardiac investigations, and a single pathologist analyzed histopathological material. There were 184 subjects with dilated cardiomyopathy. Positive viral identification or lymphocytic myocarditis was found in 30 (68.2%) of 44 cases with available early histology and 8 of 9 cases presenting with sudden death. Freedom from death or transplantation was 72% (95% CI, 65% to 78%) 1 year after presentation and 63% (95% CI, 55% to 70%) at 5 years. By proportional hazards regression analysis, risk factors for death or transplantation comprised age >5 years at presentation (hazard ratio 5.6, 95% CI, 2.6 to 12.0), familial dilated cardiomyopathy (hazard ratio, 2.9; 95% CI, 1.5 to 5.6), lower initial fractional shortening z score (hazard ratio per z-score unit, 0.75; 95% CI, 0.65 to 0.87), and failure to increase fractional shortening z score during follow-up (hazard ratio per unit increase, 0.68; 95% CI, 0.58 to 0.79). At follow-up, 78 (44.6%) of 175 cases diagnosed during life have no symptoms and are not taking any cardiac medication.

CONCLUSIONS

Early mortality is high in childhood dilated cardiomyopathy, but the clinical status of long-term survivors is good. This population-based study identifies children at risk of adverse events.

Pulmonary vein stenosis: initial experience with cutting balloon angioplasty

OBJECTIVE

To determine the safety and effectiveness of cutting balloon angioplasty for pulmonary vein stenosis (PVS).

DESIGN AND SETTING

Retrospective review of case notes and cardiac catheterisation data at the Royal Brompton Hospital.

MAIN OUTCOME MEASURES

Diameter of pulmonary vein, tricuspid regurgitant jet velocity on echocardiogram, and percutaneous oxygen saturation before and after cutting balloon angioplasty.

RESULTS

Three patients had congenital PVS and three had PVS associated with total anomalous pulmonary venous drainage. A total of 27 PVSs were treated during 12 catheterisation procedures. Median patient age at the time of procedure was 12.5 months (range 1.5-36 months) and weight was 7.1 kg (range 2.8-11.1 kg). Minimum pulmonary vein diameter increased significantly on angiography after cutting balloon angioplasty, from mean (SD) 2.3 (0.7) mm to 4.2 (1.9) mm, mean of differences 1.9 mm (95% confidence interval (CI) 0.9 to 2.9 mm, p = 0.0013). Mean (SD) oxygen saturation rose from 79.6 (12.9)% to 83.9 (9.0)%, mean of differences 4.3% (95% CI 0.7% to 8.0%, p = 0.0238). All children's symptoms improved subjectively. Tricuspid regurgitant jet velocity did not change significantly. The longest time interval before repeat intervention was six months. There were no acute deaths; one patient had a small pulmonary haemorrhage and developed a small aneurysm adjacent to the site of angioplasty.

CONCLUSION

Cutting balloon angioplasty is safe in the palliation of PVS in children. It gives some acute relief but often needs to be repeated, as improvement is rarely sustained.

Can atrioventricular septal defects exist with intact septal structures?

The hallmark of an atrioventricular septal defect (AVSD) is a common atrioventricular junction, giving rise to a trileaflet left atrioventricular valve. AVSDs have the potential for interatrial shunting alone, interventricular shunting alone, or both. AVSDs without interatrial or interventricular communications have been identified at postmortem examination, but there are no reports of AVSDs with intact septal structures diagnosed in life. Six patients are described with AVSD and intact atrial and ventricular septa diagnosed echocardiographically. This report shows that AVSDs can exist without interatrial or interventricular communications and that the characteristic feature of this condition, the common atrioventricular junction with a trileaflet left atrioventricular valve, can be diagnosed in life by using cross sectional echocardiography. AVSDs with intact septal structures may be more common than previously described.

Development of Z-scores for fetal cardiac dimensions from echocardiography

OBJECTIVES

Z-scores for cardiac dimensions are well established in postnatal life, but have yet to be developed for fetal cardiac dimensions. These would be of real advantage to the clinician in accurately quantifying size and growth of cardiac dimensions and to the researcher by allowing mathematical comparison of growth in differing subgroups of a disease. The purpose of this observational study, conducted at tertiary fetal medicine and cardiology units, was to produce formulae and nomograms allowing computation of Z-scores for fetal cardiac dimensions from knowledge of femur length (FL), biparietal diameter (BPD) or gestational age (GA) using fetal echocardiography.

METHODS

Seventeen fetal cardiac dimensions were measured in 130 pregnant women with singleton fetuses of gestational age 15-39 weeks. Regression equations were derived relating all dimensions to FL, BPD and GA. From the calculations, formulae were then developed allowing fetal cardiac Z-score computation.

RESULTS

The relationships between cardiac dimensions and FL, BPD or GA were described following natural log transformation. From this analysis, FL (taken as an expression of fetal size) had the highest correlation to fetal cardiac dimensions. From the developed nomograms, Z-scores of specific fetal cardiac structures could be estimated from knowledge of the FL, BPD or GA and echocardiographically derived measurements.

CONCLUSIONS

This study allowed computation of Z-scores in fetal life for 17 cardiac dimensions from FL, BPD or GA. Previous studies of normal data allowed qualitative assessment of where abnormal cardiac dimensions lay with regard to the normal range. Z-scores from this study allow quantitative analysis of where such dimensions lie relative to the mean. This permits exact assessment of growth of fetal cardiac structures in normal hearts and particularly in congenitally abnormal hearts where quantitative assessment of the growth of cardiac structures is important in analyzing and planning treatment strategies.

Pulmonary atresia with intact ventricular septum: Predictors of early and medium-term outcome in a population-based study

OBJECTIVES

Pulmonary atresia with intact ventricular septum is a form of congenital heart disease usually associated with right-heart hypoplasia, with considerable morphologic heterogeneity and often poor outlook. Ascertainment of risk factors for poor outcome is an important step if an improvement in outcome is to be achieved.

METHODS

The UK and Ireland Collaborative study of Pulmonary Atresia with Intact Ventricular Septum is an ongoing population-based study of all patients born with this disease from 1991 through 1995. All available clinical, morphologic, and investigative variables were directly reviewed, and risk factor analysis was performed for poor outcome.

RESULTS

One hundred eighty-three patients presented with pulmonary atresia with intact ventricular septum. Fifteen underwent no procedure, and all died. Of the remainder, 67 underwent a right ventricular outflow tract procedure (catheter or surgical), 18 underwent an outflow tract procedure with shunt, and 81 underwent a systemic-to-pulmonary shunt alone. One- and 5-year survival was 70.8% and 63.8%, respectively. Results from Cox proportional hazards model analysis showed that low birth weight (P = .024), unipartite right ventricular morphology (P = .001), and the presence of a dilated right ventricle (P < .001) were independent risk factors for death. The presence of coronary artery fistulae, right ventricular dependence, or the tricuspid valvar z score did not prove to be risk factors for death. After up to 9 years of follow-up, 29% have achieved a biventricular repair, 3% a so-called one-and-a-half ventricular repair, and 10.5% a univentricular repair, with 16.5% still having a mixed circulation (41% died).

CONCLUSIONS

This population-based study has shown which features at presentation place an infant in a high-risk group. This is important information for counseling in fetal life and for surgical strategy after birth.

Clinical Features and Outcomes of Childhood Hypertrophic Cardiomyopathy

BACKGROUND

Population-based studies have provided insight into the natural history of adult hypertrophic cardiomyopathy, but comparable information for affected children is lacking.

METHODS AND RESULTS

All Australian children who presented with primary cardiomyopathy at 0 to 10 years of age between January 1, 1987, and December 31, 1996, were enrolled in a longitudinal cohort study. A single cardiologist reviewed serial cardiac investigations on each subject. A total of 80 subjects with hypertrophic cardiomyopathy were identified. An underlying syndromal, genetic, or metabolic condition was identified in 46 subjects (57.5%). There were no cases of sudden death at presentation. Left ventricular outflow tract obstruction was present in 32 subjects (40%); right ventricular outflow obstruction was present in 10 (12.5%). Freedom from death or transplantation was 83% (95% CI, 73 to 90) 5 years after presentation and 76% (95% CI, 62 to 86) 10 years after presentation. By proportional-hazards regression analysis, risk factors for death or transplantation included concentric left ventricular hypertrophy, age at presentation <1 year, lower initial fractional shortening Z score, and increasing left ventricular posterior wall thickness relative to body surface area. At the latest follow-up, 54 of 65 surviving subjects had no symptoms, and 46 were receiving no regular medication.

CONCLUSIONS

Syndromal, genetic, and metabolic causes predominate in children with hypertrophic cardiomyopathy. Ventricular outflow tract obstruction is common. The clinical status of long-term survivors is good. This population-based study identifies children with hypertrophic cardiomyopathy who are at risk of adverse events.

Complications of supra-annular mitral valve placement in infants

Two infants underwent supra-annular placement of prosthetic mitral valves. The objective of this strategy was to insert a larger valve and delay replacement. This approach was initially successful but by two and three years later the patients developed impairment of cardiac function. The prosthesis decreased the volume and compliance of the left atrium causing high left atrial and pulmonary venous pressures. The "ventricularised" atrium below the prosthesis dilated. In neither case was it possible to delay second valve replacement.

Midline raphé, sternal cleft, and other midline abnormalities: a new dominant syndrome?

Sternal fusion defects are malformations that often present as an isolated finding. An association with multiple malformations has been reported, in particular with midline raphe and craniofacial hemangiomas and as part of the pentalogy of Cantrell. Most syndromic cases were sporadic with a few families reported with recurrence in sibs. We describe a mother and two daughters with midline raphe and sternal defects. Affected members also had double central incisors, congenital heart defect, neck webbing, bicornuate uterus and minor anomalies including long face with hypotelorism. None of the three affected relatives had hemangiomas. The manifestations of these patients do not fit any previously described condition, and we propose they represent a new syndrome. This family is also important as it points to a possible genetic cause for at least some cases of this disorder of the ventral midline.

Neonatal hemangiomatosis and atrial septal defect: a rare cause of right heart failure in infancy

Neonatal hemangiomatosis is a well-recognized cause of left ventricular failure. We describe an infant with neonatal hemangiomatosis and an ostium secundum atrial septal defect who developed severe right heart failure. This was due to the combination of increased flow through the right heart as a result of the atrial septal defect, and the background high cardiac output from the massive arteriovenous shunting and multiple hemangiomas. In addition, the multiple hepatic hemangiomas may exert a vasoactive influence on the pulmonary vasculature.

Diagnostic difficulties in a case of primary systemic carnitine deficiency with idiopathic dilated cardiomyopathy

Blood spot carnitine profiles are widely used to screen for disorders of fatty acid oxidation. This case report emphasizes that a borderline concentration of free carnitine does not exclude the diagnosis of primary carnitine deficiency. Concurrent measurement of carnitine in the plasma and urine is a more sensitive test.

The epidemiology of childhood cardiomyopathy in Australia

BACKGROUND

The incidence and age distribution of primary cardiomyopathy in children are not well defined. We undertook a population-based, retrospective cohort study in Australia to document the epidemiology of childhood cardiomyopathy.

METHODS

We analyzed all cases of primary cardiomyopathy in children who presented between 1987 and 1996 and who were younger than 10 years of age. Children were recruited from multiple sources, and cases of cardiomyopathy were classified according to World Health Organization guidelines.

RESULTS

Over the 10-year period, 314 new cases of primary cardiomyopathy were identified, for an annual incidence of 1.24 per 100,000 children younger than 10 years of age (95 percent confidence interval, 1.11 to 1.38). Dilated cardiomyopathy made up 58.6 percent of cases, hypertrophic cardiomyopathy 25.5 percent, restrictive cardiomyopathy 2.5 percent, and left ventricular noncompaction 9.2 percent of cases. The incidence of all types of cardiomyopathy except restrictive declined rapidly after infancy. In 11 cases (3.5 percent), sudden death was the first symptom. There was a male predominance among children with hypertrophic and unclassified cardiomyopathy. Indigenous children had a higher incidence of dilated cardiomyopathy than nonindigenous children (relative risk, 2.67; 95 percent confidence interval, 1.42 to 4.63) and a higher rate of death as the presenting symptom (16.7 percent vs. 2.6 percent, P=0.02). Lymphocytic myocarditis was present in 25 of 62 children with dilated cardiomyopathy (40.3 percent) who underwent cardiac histologic examination within two months after presentation.

CONCLUSIONS

Lymphocytic myocarditis and left ventricular noncompaction are important causes of childhood cardiomyopathy in Australia. The timing and severity of presentation in children with cardiomyopathy are related to the type of cardiomyopathy, as well as to genetic and ethnic factors.

Pulmonary atresia with intact ventricular septum: range of morphology in a population-based study

OBJECTIVES

We describe the morphologic variability in pulmonary atresia with intact ventricular septum (PAIVS) within a population-based study.

BACKGROUND

An uncommon disease, PAIVS shows considerable morphologic heterogeneity. Clinical reports, based mostly on small samples of patients, may not reflect the true spectrum of pathology of this condition. We have studied the entire range of morphology in a prospective population-based study of patients over a five-year period (1991 to 1995). METHODS; As part of the United Kingdom and Ireland Collaborative Study of PAIVS, all 18 pediatric cardiac centers were visited by a single investigator. Morphologic features of each case were determined by direct review of the echocardiograms and angiocardiograms, from surgical and autopsy reports, and by review of pathology specimens where available.

RESULTS

Among 183 live-born infants, atresia was valvar (membranous) in 74.7% and muscular in 25.3%. Muscular obliteration of the apical trabecular cavity, and in some cases its infundibulum, resulted in "bipartite" right ventricle (RV) in 33.6%, and a "unipartite" chamber in 7.7%. The remaining 58.7% had "tripartite" morphology. Coronary arterial abnormalities were identified in 45.8%, including arterial stenoses, interruptions and ectasia in 7.6%. Ebstein's malformation coexisted in 18 patients. Median tricuspid valvar size and RV inlet Z-scores were -5.2 and -5.1, respectively.

CONCLUSIONS

This study provides unique data on the diverse pathology of PAIVS in an unselected population. This will help determine if published reports reflect the true spectrum of pathology of the condition.