Outcomes of Contemporary Family Screening in Hypertrophic Cardiomyopathy

Background:

Contemporary hypertrophic cardiomyopathy (HCM) family screening includes clinical evaluation and genetic testing (GT). This screening strategy requires the identification of a pathogenic mutation in the proband. Our aim was to examine the results of this HCM screening strategy.

Methods:

Between 1985 and 2016, 777 relatives of 209 probands were assessed in the context of HCM screening. Genotype-positive (G+) relatives and relatives without genetic testing (GT) underwent repeated clinical evaluations. In genotype-negative (G-) relatives mortality was assessed during follow-up.

Results:

A pathogenic mutation was identified in 72% of probands. After counseling, GT was performed in 620 (80%) relatives: 264 (43%) were G+ (age 41±18 y) and 356 (57%) were G- (age 48±17 y). At first screening, HCM was diagnosed in 98 (37%) G+ relatives and 28 (17%) relatives without GT ( p <0.001). During 9 years follow-up of relatives diagnosed with HCM, 8 (6%) underwent septal reduction therapy, 16 (16%) received primary prevention ICDs, and cardiac mortality was 0.3%/year. During 7 years follow-up of relatives without HCM, 29 (16%) developed HCM. Survival at 5/10 years was 99%/95% in G+ relatives, 97%/94% in G- relatives ( p =0.8), and 100%/100% in relatives without GT.

Conclusions:

HCM was identified in 30% of relatives at first screening, and 16% developed HCM during 7 years of repeated evaluation. GT led to a discharge from clinical follow-up in 46% of the study population. Survival in the relatives was good.

[Surgical treatment of hypoplastic left heart syndrome: limited success]

OBJECTIVE

To inventory the treatment of hypoplastic left heart syndrome (HLHS) in the Netherlands and its results.

DESIGN

Retrospective.

METHOD

Data were collected from all patients (n = 117) diagnosed with HLHS in the Wilhelmina Children's Hospital-University Medical Center Utrecht and the University Hospital Rotterdam-Sophia Children's Hospital and born in the period 1 March 1988-31 May 2000. Type and time of intervention, and mortality were recorded and cumulative survival was analysed by Kaplan-Meier analysis. Cumulative survival was compared between early and late series and between the two hospitals.

RESULTS

The study group comprised 68 boys and 49 girls, all neonates. At the time of the investigation, the mean duration of follow-up was 185 days (range: 0-3855). Fifty-eight children had received no treatment; all of these had died. Fifty-nine children were scheduled for the Norwood procedure; six of them died before operation. The 53 patients who underwent the first stage of the Norwood procedure had 1-month, 1-year, 2-year, and 5-year survival chances of 55%, 30%, 27%, and 24% respectively. Survival chances between the two time periods and the two hospitals showed no significant differences.

CONCLUSION

The Norwood procedure was performed in almost half of the children with HLHS. It is only moderately successful; however, it seems the only realistic choice in the management.

Chromosome 22q11 deletions in patients with selected outflow tract malformations

The incidence of 22q11 deletions and its effect on the phenotype were established in 170 patients with selected outflow tract malformations and transposition of the great arteries (conotruncal defects). Cases were seen both prospectively and retrospectively. All patients had a dysmorphological evaluation by the clinical geneticist and a cytogenetic analysis including FISH analysis for 22q11 deletions. A chromosomal abnormality was present in 29 patients, including a 22q11 deletion in 22/170 patients (13%). The 22q11 deletion was found in 11% of tetralogy of Fallot, in 11% of pulmonary atresia and VSD, in 44% of pulmonary atresia. VSD and collateral arteries, in 20% of truncus arteriosus, in 60% of interrupted aortic arch and in 25% patients with aberrant subclavian artery. They were absent in double outlet right ventricle or in transposition of the great arteries. No parental deletion was found. All patients had clinical characteristics of the velocardiofacial syndrome. This study confirms a high incidence of chromosome 22q11 deletions in patients with selected outflow tract malformations, with great clinical impact for further management and genetic counseling.

In utero diagnosis of infra-diaphragmatic total anomalous pulmonary venous return

This report describes the diagnosis of infra-diaphragmatic total anomalous pulmonary venous return in a fetus at 25 weeks of gestation. Abnormal venous pathways were visualized with real-time, pulsed and color Doppler ultrasound. The growth of cardiac structures, especially the left ventricle, was evaluated during subsequent ultrasound examinations.

Multiple intracardiac tumors: spontaneous prenatal recovery of fetal bradyarrhythmia

Although prenatally detected intracardiac tumors are reported to have a poor prognosis, tumor regression and even tumor disappearance have been observed during childhood. A case of prenatal cessation of fetal cardiac tumor growth and return of cardiac arrhythmia to normal sinus rhythm is presented.

Efficacy of routine fetal ultrasound screening for congenital heart disease in normal pregnancy

BACKGROUND

Second trimester routine ultrasound evaluation of the fetal heart by means of the four-chamber view has been proposed for prenatal detection of cardiac anomalies. The aim of this study was to evaluate the efficacy of this procedure.

METHODS AND RESULTS

A prospective follow-up study on 6922 scanned fetuses was performed. Pregnant women without known risk factors who were scheduled for a routine fetal ultrasound examination between 16 and 24 weeks gestation were invited to participate. Follow-up until 6 months postpartum was available for 5660 subjects (81.8%), of whom 5319 fulfilled all eligibility criteria. by comparing the prenatal diagnosis to the postnatal diagnosis, we obtained sensitivity, specificity, and predictive value (positive and negative). A total of 80 cases of congenital malformations were diagnosed during the study: 44 cases of congenital heart disease, 40 cases of noncardiac malformations, and a combination of the two in 4 cases. The fetal four chamber-view examination was considered abnormal in 7 women who were subsequently referred for extensive fetal ultrasound examination. Two proved to be carrying an affected fetus. Similarly, prenatal referral of 14 women because of suspected noncardiac malformations yielded 12 such cases. The fetal four chamber-view examination had a sensitivity of 4.5% (95% CI, 0.6% to 15%). Sensitivity for noncardiac anomalies was 30% (95% CI, 16.6% to 46.5%). Overall sensitivity of ultrasound examination was 16.3% (95% CI, 2.09% to 48.8%). Specificity and negative predictive value were high (>98%). The positive predictive value was low with wide CIs.

CONCLUSIONS

These results suggest that the current mode of routine prenatal ultrasound screening for congenital malformations is inefficient, particularly for cardiac anomalies.

The efficacy of flecainide versus digoxin in the management of fetal supraventricular tachycardia

Fetal supraventricular tachycardia (SVT) can be successfully treated transplacentally, but in cases where fetal hydrops develops there is considerable morbidity and mortality. The present study was carried out to establish whether the introduction of flecainide altered obstetric management and fetal outcome. A retrospective analysis took place of 51 singleton pregnancies which were referred to the division of prenatal diagnosis because of fetal tachycardia between 1982 and 1993. SVT was documented in 50 out of 51 fetuses, one of which displayed a combination of extensive rhabdomyomas and severe hydrops and died shortly after referral. In the other fetus ventricular tachycardia was diagnosed. Of the remaining 49 fetuses, 14 did not receive any prenatal treatment, but nine needed postnatal treatment. Transplacental treatment of SVT took place in 35 fetuses, of which 22 presented without hydrops and 13 with hydrops. These subsets differed significantly with respect to restoration of normal sinus rhythm (73% vs. 30%; p < 0.001) and mortality (0% vs. 46%; p < 0.001). Digoxin was effective in restoring sinus rhythm in 55 per cent of the non-hydropic fetuses but in only eight per cent of the hydropic fetuses. Flecainide was effective in restoring sinus rhythm in all non-hydropic fetuses where digoxin treatment failed, and in 43 per cent of hydropic fetuses. Administration of flecainide resulted in a significantly reduced mortality (p < 0.001) compared with digoxin treatment. No adverse effects were seen. Postnatal anti-arrhythmic treatment was necessary in 23 infants. Treatment could be withdrawn within one year in all cases but one.

Aspects of the aetiology of congenital heart disease

A concise overview of current knowledge on the aetiology of congenital heart disease is provided. At present, only 10 to 20% of the cases occurring in neonates can be attributed to known risk factors. Recurrence within relatives, chromosomal anomalies, genetic disorders, maternal disease and teratogen exposure are addressed briefly; contemporary research models and methods, e.g. embryology and genetics and molecular biology, are referred to. A major innovation has been the introduction of the concept of common pathogenetic pathways. Thus, different teratogenic factors or risk-factors may affect normal development at an identical stage and cause similar malformations. Also, the importance of timing of an event is stressed. If the time frame of exposure does not coincide with embryogenesis any teratogenic effect may be missed. Large-scale epidemiological studies on fetuses and neonates with congenital heart disease are introduced as a third mode of research on the aetiology, although this approach is not used efficiently at present; cases of intra-uterine death can be considered a valuable source of information that needs further attention. Combined, the above three lines of research may prove productive, but the design of a comprehensive research project would need to be handled carefully. Possibilities for prevention of the occurrence of cardiovascular malformations are reported. Through lack of knowledge of causality, at present, only secondary prevention may be possible and hence deserves attention. However, there appears to be no provision for thorough pre-natal screening tests for congenital heart disease in an unselected population.

Clinical significance of maternal anti-Ro/SS-A antibodies in children with isolated heart block

OBJECTIVES

We studied 30 consecutive children with isolated heart block to assess the clinical impact of the presence of maternal anti-Ro/SS-A antibodies for isolated heart block.

BACKGROUND

Isolated heart block in children, often associated with maternal autoimmune disease leading to anti-Ro/SS-A auto-antibody production, is an infrequent but potentially lethal disorder.

METHODS

Thirty children with isolated heart block were studied with respect to medical history and electrocardiographic (ECG) analysis. The presence of anti-Ro/SS-A antibodies was determined in the maternal serum. We also examined the ECGs of all brothers and sisters of the patients for conduction abnormalities.

RESULTS

Twenty-one of the 30 children had an anti-Ro/SS-A-positive mother (group A); the other 9 children had an anti-Ro/SS-A-negative mother (group B). Comparison of the clinical data from both mothers and children revealed that these two groups differed significantly with respect to the following: Prenatal diagnosis and obstetric complications occurred more often in group A, whereas progression to complete block, QRS width > 0.08 s, premature ventricular contractions and ventricular standstills > 4.5 s occurred more often in group B. In addition, mothers of children in group A reported more spontaneous abortions. All siblings of children in groups A and B had normal ECGs, excluding a subclinical form of heart block.

CONCLUSIONS

Two types of heart block can be recognized: Congenital heart block is associated with maternal anti-Ro/SS-A antibodies and numerous obstetric and neonatal complications. It is diagnosed prenatally or at birth and is usually complete at onset and probably has a substantial recurrence risk. Heart block that is acquired later in life is not associated with maternal autoimmunity and has no risk for recurrence. It often presents as a partial block but progresses to complete block in time.

Maternal autoantibodies and congenital heart block: no evidence for the existence of a unique heart block-associated anti-Ro/SS-A autoantibody profile

One of the rare examples of the transfer of autoimmune disease from mother to (unborn) child is the neonatal lupus syndrome. This syndrome comprises the development of fetal heart disease (congenital heart block) or neonatal skin rash and is specifically associated with maternal anti-Ro/SS-A autoantibodies. Previous studies have suggested that especially maternal autoantibody reactivity against the 52 kDa protein of the Ro/SS-A antigen and/or against the La/SS-B antigen is responsible for the development of congenital heart block (CHB). To determine the CHB-associated antibody response in more detail, we analysed the presence of autoantibodies in sera from mothers of children with isolated heart block. All 14 mothers of children with congenital heart block were positive for anti-Ro/SS-A antibodies. Remarkably, their antibody profile, including recognition of different Ro/SS-A proteins and autoantibody levels against these proteins, did not differ from anti-Ro/SS-A positive mothers of healthy children. In contrast, all 8 anti-Ro/SS-A negative mothers had children with acquired heart block. We conclude from our data that maternal anti-Ro/SS-A antibodies are essential for CHB but that fine analysis of this autoantibody response does not predict the occurrence of CHB.

Short- and midterm results of balloon valvuloplasty for valvular aortic stenosis in children

During a 27-month period, 21 consecutive children (aged 0.1 to 15.7 years) with isolated valvular aortic stenosis underwent percutaneous transfemoral balloon valvuloplasty. Ten children had undergone earlier surgical valvulotomy. The indication for treatment was ST-T-segment changes at rest or during bicycle-ergometry, a continuous-wave Doppler-derived transvalvular gradient greater than 60 mm Hg or syncope, or a combination. Mean peak systolic left ventricular pressure decreased from 165 +/- 19 to 131 +/- 19 mm Hg (p less than 0.001). Mean end-diastolic left ventricular pressure did not change significantly (12 +/- 3 vs 11 +/- 5 mm Hg). Mean peak systolic valve gradient decreased from 71 +/- 23 to 22 +/- 11 mm Hg (p less than 0.001). Mean cardiac index remained unchanged (2.9 +/- 0.8 vs. 3.0 +/- 0.7 liters.min-1.m-2). Aortic valve regurgitation on angiography appeared or increased in 9 patients (up to grade 3 in 3 children). Noninvasive follow-up studies were performed for 2 to 4.2 years (mean 2.8). ST-T changes on the electrocardiogram at rest or during exercise were present in 6 patients before balloon valvuloplasty and had disappeared in all at 6-month follow-up. Reoccurrence of ST-T changes after a longer follow-up was associated with severe valve regurgitation. Syncope was not observed after balloon valvuloplasty. The continuous-wave Doppler gradient decreased from 94 +/- 36 to 49 +/- 15 mm Hg (p less than 0.001). After a follow-up of 2 to 4.2 years (mean 2.8) it remained unchanged (43 +/- 13 mm Hg; p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Management of fixed subaortic stenosis: a retrospective study of 57 cases

Although recommended by several investigators, the benefit of early surgery in patients with fixed subaortic stenosis has not been proved. Findings were reviewed of 57 patients with isolated fixed subaortic stenosis, including 27 surgically treated patients, with special emphasis on the occurrence of aortic regurgitation during a mean follow-up period of 6.7 years. The number of patients with aortic regurgitation increased preoperatively in the total group (23% at diagnosis to 54% after 3.7 years of follow-up). The prevalence of aortic regurgitation in the 27 surgically treated patients was higher (81%) than that in the nonsurgically treated group but remained unchanged after a mean postoperative period of 4.7 years. In all patients but one, aortic regurgitation remained of minor hemodynamic significance. One patient died during follow-up. After surgery, 15 patients (55%) showed a relapse; 11 redeveloped a subvalvular pressure gradient greater than 30 mm Hg and discrete subvalvular ridges (range 6 months to 24 years after surgery, mean 7 years). In those patients with fixed subaortic stenosis, follow-up did not reveal any benefit from early surgery. The unpredictable course and sometimes very severe progression of this disease make frequent and careful follow-up necessary.

[Glomerular filtration in premature infants]

Many methods for measuring glomerular filtration rate in preterm newborns are known. However only the classic inulin clearance as well as the continuous inulin infusion technique provide exact data, but are not easy to perform. In general pediatric practice the use of tables for 'normal values' of serum creatinine compared to serum creatinine levels of patients if useful.

The effect of ACTH stimulation on plasma steroids in two patients with congenital hypoaldosteronism and in their relatives

In two children with isolated congenital hyperreninaemic hypoaldosteronism, as well as in their relatives, plasma levels of aldosterone (Aldo), corticosterone (B), deoxycorticosterone (DOC), 18-OH-B and 18-OH-DOC were measured before and after an iv bolus of 0.25 mg Synacthen (Ciba). A corticosterone methyl oxidase deficiency type II was demonstrated in one child. Her normoreninaemic parents (no consanguinity) had plasma values consistent with heterozygosity. The results in the other child and one asymptomatic sib were compatible with a partial corticosterone methyl oxidase deficiency type I. His parents were consanguine but had normal Aldo levels. Overnight dexamethasone administration did not suppress any of the steroids measured except cortisol, suggesting synthesis of these steroids by the zona glomerulosa.