Proposal for a new definition of congenital complete atrioventricular block

Influence of improved antenatal detection on the outcomes of complete atrioventricular block diagnosed in fetal-neonatal life and childhood periods - a single-centre experience in South Wales for 55 years

OBJECTIVE

This study aimed to analyse the influence of improved antenatal detection on the course, contemporary outcomes, and mortality risk factors of the complete atrioventricular block during fetal-neonatal and childhood periods in South Wales.

METHODS

The clinical characteristics and outcomes of complete atrioventricular block in patients without structural heart disease at the University Hospital of Wales from January 1966 to April 2021 were studied. Patients were divided into two groups according to their age at diagnosis: I-fetal-neonatal and II-childhood. Contemporary outcomes during the post-2001 era were compared with historical data preceding fetal service development and hence earlier detection.

RESULTS

There were 64 patients: 26 were identified in the fetal-neonatal period and the remaining 38 in the childhood period. Maternal antibodies/systemic lupus erythematosus disease (anti-Ro/Sjögren's-syndrome-related Antigen A and/or anti-La/Sjögren's-syndrome-related Antigen B) were present in 15 (57.7%) of the fetal-neonatal. Fetal/neonatal and early diagnosis increased after 2001 with an incidence of 1:25000 pregnancies. Pacemaker implantation was required in 34 patients, of whom 13 were diagnosed in the fetal-neonatal group. Survival rates in cases identified before 2001 were at 96.3% (26/27), whereas it was 83.8% (31/37) in patients diagnosed after 2001 (P > 0.05). Other mortality risk factors comprised a lower gestational week at birth, maternal antibodies, and an average ventricular heart rate of < 55 bpm.

CONCLUSIONS

Fetal diagnosis of complete atrioventricular block is still portends high fetal and neonatal mortality and morbidity despite significantly improved antenatal detection after 2001. Pacemaker intervention is needed earlier in the fetal-neonatal group. Whether routine antenatal medical treatment might alter this outcome calls for further prospective multicentre studies.

Experience of treating congenital complete atrioventricular block with epicardial pacemaker in infants and young children: a retrospective study

BACKGROUND

This article summarizes the treatment experience for congenital complete atrioventricular block (CCAVB) in newborns and infants, and discusses the necessity and feasibility of treating CCAVB with permanent pacemaker implantation in this population.

METHODS

In this study, the clinical data and follow-up results of nine children admitted at our center with CCAVB from January 2005 to March 2023 were retrospectively analyzed. Among them, two children received early implantation of permanent pacemakers (within 1 year of age), two children received non-early implantation (1 year or older), and the remaining five children received no pacemaker implantation. CCAVB diagnosis was confirmed by clinical symptoms and clinical examinations, including electrocardiography and echocardiography before surgery. After surgery, the pacing and sensing functions of the pacemaker were observed using electrocardiography, echocardiography, and pacing threshold monitoring. A comprehensive assessment of the treatment efficacy was conducted, encompassing improvements in clinical symptoms, growth and development, as well as the absence of any additional potential complications. The children who did not receive pacemaker implantation were followed up.

RESULTS

Among the four children who successfully received pacemaker implantation, one child who received non-early implantation died. For the remaining three children, the threshold level, amplitude, impedance, and minute ventilation sensor function of the pacemaker were good during the follow-up period, with a heart rate at the pacing rate. The growth and development of the aforementioned patients who received pacemaker implantation demonstrated adherence to the percentile curve, and their motor and cognitive development remained unaffected. However, among the children who did not undergo pacemaker implantation, two experienced death, while three were lost to follow-up, thereby limiting the evaluation of their long-term outcomes.

CONCLUSIONS

Early implantation of an epicardial pacemaker at an early stage in newborns and infants diagnosed with CCAVB can significantly improve clinical symptoms without affecting their growth and development. These data are in line with current literature and suggest that early implantation of an epicardial pacemaker in newborns and infants diagnosed with CCAVB but further studies are needed.

Congenital Heart Block

Congenital complete heart block (CCHB) defines atrioventricular conduction abnormalities diagnosed in utero or within the first 27 days of life. Maternal autoimmune disease and congenital heart defects are most commonly responsible. Recent genetic discoveries have highlighted our understanding of the underlying mechanism. Hydroxychloroquine shows promise in preventing autoimmune CCHB. Patients may develop symptomatic bradycardia and cardiomyopathy. The presence of these and other specific findings warrants placement of a permanent pacemaker to relieve symptoms and prevent catastrophic events. The mechanisms, natural history, evaluation, and treatment of patients with or at risk for CCHB are reviewed.

Management of Complete Heart Block in a Pregnant Woman with Systemic Lupus Erythematosus-Associated Complications: Treatment Considerations and Pitfalls

We present a case of a pregnant woman with systemic lupus erythematosus (SLE) who was diagnosed with asymptomatic complete heart block (CHB) during pregnancy. To evaluate possible risks and benefits of pacemaker (PM) implantation, a multidisciplinary counselling board was held. Its recommendation was to perform PM implantation to prevent intra-uterine growth restriction from insufficient cardiac output using a fluoroscopic protective shield. The procedure was performed without complications and established permanent pacing on onwards ECG examinations. The patient subsequently gave birth to a healthy newborn. After a retrospective clinical case evaluation and review of relevant literature, a presumptive association between CHB and the primary diagnosis was proposed. Above that, pregnant women with SLE who develop hypertension are commonly treated with methyldopa, which may cause conduction abnormalities. Clinical recommendations for young female patients expecting pregnancy are lacking in this area. Careful diagnostic and treatment approaches should be used in the management of possible SLE-related complications in women of child-bearing age, focusing on preventable events.

Third Trimester Fetal Heart Rates in Antibody-Mediated Complete Heart Block Predict Need for Neonatal Pacemaker Placement

Congenital complete heart block (CCHB) affects 1 in 20,000 newborns. This study evaluates fetal and neonatal risk factors predictive of neonatal pacemaker placement in antibody-mediated complete heart block. The Children's Hospital Los Angeles institutional fetal, pacemaker, and medical record databases were queried for confirmed SSA/SSB cases of CCHB between January 2004 and July 2019. Cases excluded were those with a diagnosis beyond the neonatal period, diagnosis of a channelopathy, or if maternal antibody status was unknown. We recorded the gestational age (GA), birth weight (BW), fetal heart rates (FHRs) of the last echocardiogram before delivery, specific neonatal ECG and echocardiogram findings, age at pacemaker placement, and mortality. Of 43 neonates identified with CCHB, 27 had confirmed maternal antibody exposure. Variables associated with neonatal pacemaker implantation were FHRs < 50 bpm (p = 0.005), neonatal heart rates < 52 bpm (p = 0.015), and neonatal left ventricular fractional shortening (FS) percentages < 34% (p = 0.03). On multivariate analysis, FHR remained significant (p = 0.03) and demonstrated an increased risk of neonatal pacemaker placement by an odds ratio of 12.5 (95% CI 1.3-116, p = 0.05). The median GA at which the FHR was obtained was 34 weeks (IQR 26-35 weeks). Neonatal pacemaker placement was highly associated with a FHR < 50 bpm, neonatal HR < 52 bpm, and neonatal FS < 34%. FHRs at 34 weeks GA (IQR 26-35 weeks) correlated well with postnatal heart rates and were predictive of neonatal pacemaker placement.

Outcomes in Congenital and Childhood Complete Atrioventricular Block: A Meta-analysis

BACKGROUND

The long-term outcomes of patients with congenital and childhood complete atrioventricular block (CCAVB/ CAVB) after pacemaker implantation are unclear.

METHODS

We performed a meta-analysis of all the studies of CCAVB. A systematic search of PubMed and CENTRAL databases from 1^st January 1967 to 31^st January 2020 was performed. The quality of studies included was critically appraised using the Newcastle-Ottawa scale, and outcome data were analyzed using the restricted maximum likelihood function.

RESULTS

Twenty-nine studies were eligible for analysis, with a total of 1553 patients. The all-cause-mortality was 5.7 % [95% CI: 2.5-9.9%], while PICM was seen in 3.8% [95% CI: 1.2-7.2]. Diagnosis at birth [effect size (ES)(95%CI): -2.23 (-0.36 to -0.10); p<0.001], presence of congenital heart disease ([ES(95%CI): -0.67 (0.41 to 0.93); p<0.001], younger age at pacemaker implantation ([ES(95%CI): -0.01 (-0.02 to -0.001); p=0.02], and duration of pacing [ES(95%CI): -0.03 (-0.05 to -0.003); p=0.03], were associated with an higher mortality on binominal logistic regression. None of the parameters were significant on multivariate analysis.

CONCLUSION

Pooled proportional mortality in patients with CCAVB and CAVB is 5.7% with an infrequent incidence of PICM (3.8%) in the paced patients with AVB suggesting that pacing in these patients is an effective management strategy with a low incidence of long-term side effects. Registry and randomized data can throw additional light regarding the natural history and appropriate management strategy in these patients. This article is protected by copyright. All rights reserved.

Cohort study of congenital complete heart block among preterm neonates: a single-center experience over a 15-year period

Congenital complete heart block (CCHB) is a very rare condition, with high risk of mortality. Prematurity is associated with immaturity of the cardiovascular system. Morbidity related to CCHB and prematurity has never been described. We describe a tertiary perinatal center experience over a 15-year period on CCHB management and complications in preterm infants. This is a single-center observational cohort study. All neonates admitted to neonatal intensive care unit with a diagnosis of isolated CCHB between January 2006 and January 2021 were identified. All preterm neonates (< 37 weeks) were compared with a control cohort of term neonates (≥ 37 weeks). Antenatal data, complications of prematurity, medical, and surgical management of CCHB were recorded. Twenty-four neonates with isolated CCHB (16 preterm and 8 term) were born during the study period, including 5 very preterm (< 32 weeks) and 11 preterm (32 to 37 weeks). All very preterm were born via emergency caesarian section without antenatal steroid administration. They had multiple severe morbidities including chronic lung disease, necrotizing enterocolitis, grades 3-4 intraventricular hemorrhage, cystic periventricular leukomalacia, and longer periods of mechanical and non-invasive ventilatory support than preterm. Thirteen out of sixteen preterm infants had permanent pacemakers inserted, compared to 1/8 for term newborns. All babies born before 35-week gestation were either paced or died.Conclusion: Premature neonates with CCHB have high risk of mortality and morbidity especially if undiagnosed and born by unnecessary emergency caesarian section without antenatal steroids. Prematurity below 35 weeks may be associated with death or pacemaker insertion. This supports better antenatal screening to avoid induced prematurity. What is Known: • Congenital complete heart block is a very rare condition associated with high morbidity and mortality. • Antenatal risk factors for poor outcome include fetal hydrops, low ventricular rate (HR <55 beats per minute), and congenital heart defect. What is New: • Infants born <32 weeks with CCHB had no antenatal steroid administration, and sustained high burden of morbidity (chronic lung disease, intraventricular hemorrhage, and cystic periventricular leukomalacia). • Birth <35 weeks is strongly associated with requiring pacing prior to discharge or death.

Congenital Heart Block

Congenital complete heart block (CCHB) defines atrioventricular conduction abnormalities diagnosed in utero or within the first 27 days of life. Maternal autoimmune disease and congenital heart defects are most commonly responsible. Recent genetic discoveries have highlighted our understanding of the underlying mechanism. Hydroxychloroquine shows promise in preventing autoimmune CCHB. Patients may develop symptomatic bradycardia and cardiomyopathy. The presence of these and other specific findings warrants placement of a permanent pacemaker to relieve symptoms and prevent catastrophic events. The mechanisms, natural history, evaluation, and treatment of patients with or at risk for CCHB are reviewed.

Home fetal heart rate monitoring in anti Ro/SSA positive pregnancies: Literature review and case report

Anti-Ro/SSA antibodies are associated with a risk of 1-2 % to develop complete atrioventricular block (AVB) in fetuses of positive mothers. Complete AVB is irreversible, but studies suggest that anti-inflammatory treatment during the transition period from a normal fetal heart rate (FHR) to an AVB might stop this progression and restore sinus rhythm. The most efficient method for diagnostic evaluation of this arrhythmia is the pulsed-Doppler fetal echocardiography. However, weekly or bi-weekly recommended fetal echocardiographic surveillance can rarely identify an AVB in time for treatment success, also because the transition from a normal rhythm to a third degree AVB is very fast. Daily FHR monitoring in a medical facility could increase the chances of identifying the AVB onset but is difficult to realize. For this reason, an alternative method of FHR monitoring, performed directly by mothers in their home context, has been recently proposed. We present a case report utilizing this approach and review the current evidence about this condition.

Interferons and innate immune activation in autoimmune congenital heart block

Autoimmune congenital heart block (CHB) may develop in foetuses of women carrying anti-Ro/SSA and La/SSB autoantibodies and is characterized by disruption of signal conduction at the atrioventricular (AV) node, resulting in partial or complete AV block. If not fatal in utero, complete CHB typically requires lifelong cardiac pacing. No treatment has so far been unequivocally demonstrated to prevent or treat autoimmune CHB, and the relatively low incidence (1%-5%) and recurrence (12%-16%) rates of second/third-degree AV block add to the complexity of managing pregnancies in women with anti-Ro/La antibodies. Altogether, a better understanding of events leading to development of autoimmune CHB is needed to improve surveillance and treatment strategies. In the past decade, studies have started to look beyond the role of maternal autoantibodies in disease pathogenesis to assess other contributing factors such as foetal genetics and, more recently, immune responses in foetuses and neonates of anti-Ro/La antibody-positive women. In this review, we provide an update on the epidemiology, clinical presentation and current treatment approaches of autoimmune CHB, summarize the previously proposed pathogenic mechanisms implicating maternal autoantibodies, and discuss the recent findings of type I interferon (IFN) and innate immune activation in foetuses with autoimmune CHB and in neonates of anti-Ro/La antibody-positive mothers, and how these may contribute to autoimmune CHB pathogenesis.

Longitudinal Analysis of Fetal Ventricular Rate for Risk Stratification in Immune Congenital Heart Block

OBJECTIVES

To assess the perinatal risks of immune complete congenital heart block (iCCHB) based on the longitudinal analysis of fetal heart rate.

METHODS

Retrospective analysis of a cohort of grade III congenital heart block diagnosed in utero, in the absence of associated cardiac defect, with positive maternal serum antibodies. Longitudinal measurements of the fetal heart rate were used to estimate the average slope of ventricular rate as a function of gestational age. We then defined the following prognostic stratification based on longitudinal follow-up observations: the high-rate (HR) group included cases for which all prenatal ventricular rate measurements were above the age-specific mean of our population of iCCHB and the low-rate (LR) group included those with at least one observation below the mean during follow-up. The 2 groups were compared to analyze the potential relationship between prenatal ventricular rate and adverse neonatal outcome defined by in utero or perinatal death, neonatal heart rate <50 bpm, or hemodynamic failure requiring emergency pacing.

RESULTS

Forty-four cases were studied. Overall, the average heart rate significantly decreased during gestation from 65 bpm at 20 weeks to 55 bpm at 38 weeks. The HR and LR groups included 18 (41%) and 26 (59%) cases, respectively. Adverse perinatal outcome occurred in 1/18 (6%) and 22/26 (85%) cases in the HR and LR groups, respectively (p < 0.001). In the HR group, 33% of cases remained nonpaced at >6 months. The positive predictive values and negative predictive values for adverse perinatal outcome in the LR group were 85% (22/26) and 94% (17/18), respectively (100 and 80% <30 weeks and 88 and 78% at ≥30 weeks).

CONCLUSIONS

The prognostic classification we developed based on longitudinal heart rate assessment may be used in the late 2nd or early 3rd trimester to identify iCCHB cases at high risk of adverse perinatal outcome. This prognostic stratification should help refine counseling and perinatal management earlier in pregnancy instead of waiting for late gestation or predelivery assessment.

Natural killer cells and type II interferon in Ro/SSA and La/SSB autoantibody-exposed newborns at risk of congenital heart block

OBJECTIVE

Congenital heart block (CHB) with immune cell infiltration develops in the fetus after exposure to maternal Ro/La autoantibodies. CHB-related serology has been extensively studied, but reports on immune-cell profiles of anti-Ro/La-exposed neonates are lacking. In the current study, we characterised circulating immune-cell populations in anti-Ro/La+mothers and newborns, and explored potential downstream effects of skewed neonatal cell populations.

METHODS

In total, blood from mothers (n=43) and neonates (n=66) was sampled at birth from anti-Ro/La+ (n=36) and control (n=30) pregnancies with or without rheumatic disease and CHB. Flow cytometry, microarrays and ELISA were used for characterising cells and plasma.

RESULTS

Similar to non-pregnant systemic lupus erythematosus and Sjögren-patients, anti-Ro/La+mothers had altered B-cell subset frequencies, relative T-cell lymphopenia and lower natural killer (NK)-cell frequencies. Surprisingly, their anti-Ro/La exposed neonates presented higher frequencies of CD56^dimCD16^hi NK cells (p<0.01), but no other cell frequency differences compared with controls. Type I and II interferon (IFN) gene-signatures were revealed in neonates of anti-Ro/La+ pregnancy, and exposure of fetal cardiomyocytes to type I IFN induced upregulation of several NK-cell chemoattractants and activating ligands. Intracellular flow cytometry revealed IFNγ production by NK cells, CD8⁺ and CD4⁺ T cells in anti-Ro/La exposed neonates. IFNγ was also detectable in their plasma.

CONCLUSION

Our study demonstrates an increased frequency of NK cells in anti-Ro/La exposed neonates, footprints of type I and II IFN and an upregulation of ligands activating NK cells in fetal cardiac cells after type I IFN exposure. These novel observations demonstrate innate immune activation in neonates of anti-Ro/La+pregnancy, which could contribute to the risk of CHB.

Congenital heart block: Pace earlier (Childhood) than later (Adulthood)

Congenital complete heart block (CCHB) occurs in 2-5% of pregnancies with positive anti-Ro/SSA and/or anti-La/SSB antibodies, and has a recurrence rate of 12-25% in a subsequent pregnancy. After trans-placental passage, these autoantibodies attack and destroy the atrioventricular (AV) node in susceptible fetuses with the highest-risk period observed between 16 and 28 weeks' gestational age. Many mothers are asymptomatic carriers, while <1/3 have a preexisting diagnosis of a rheumatic disease. The mortality of CCHB is predominant in utero and in the first months of life, reaching 15-30%. The diagnosis of CCHB can be confirmed by fetal echocardiography before birth and by electrocardiography after birth. Whether early in-utero detection and treatment might prevent or reverse this condition remains controversial. In addition to autoantibody-associated CCHB, there is also an isolated (absent structural heart disease) nonimmune early- or late-onset heart block detected later in childhood that may be associated with specific genetic markers or other pathogenic mechanisms. In isolated immune or non-immune CCHB, cardiac pacemakers are implanted in symptomatic patients, however, data on the natural history of CCHB in the adult life indicate that all patients, even if asymptomatic, should receive a pacemaker when first diagnosed. However, important issues have emerged in these patients wherein life-long conventional right ventricular apical pacing may produce left ventricular dysfunction (pacing-induced cardiomyopathy) necessitating a priori alternate site pacing or subsequent upgrading to biventricular pacing. All these issues are herein reviewed and two algorithms are proposed for diagnosis and management of CCHB in the fetus and in the older individual.

Prenatal diagnosis and management of congenital complete heart block

Congenital complete heart block (CCHB) is a life-threatening medical condition in the unborn fetus with insufficiently validated prenatal interventions. Maternal administration of medications aimed at decreasing the immune response in the fetus and beta-agonists intended to increase fetal cardiac output have shown only marginal benefits. Anti-inflammatory therapies cannot reverse CCHB, but may decrease myocarditis and improve heart function. Advances in prenatal diagnosis and use of strict surveillance protocols for delivery timing have demonstrated small improvements in morbidity and mortality. Ambulatory surveillance programs and wearable fetal heart rate monitors may afford early identification of evolving fetal heart block allowing for emergent treatment. There is also preliminary data suggesting a roll for prevention of CCHB with hydroxychloroquine, but the efficacy and safety is still being studied. To date, intrauterine fetal pacing has not been successful due to the high-risk invasive placement techniques and potential problems with lead dislodgement. The development of a fully implantable micropacemaker via a minimally invasive approach has the potential to pace fetal patients with CCHB and thus delay delivery and allow fetal hydrops to resolve. The challenge remains to establish accepted prenatal interventions capable of successfully managing CCHB in utero until postnatal pacemaker placement is successfully achieved.

First Report of the Italian Registry on Immune-Mediated Congenital Heart Block (Lu.Ne Registry)

Objective: Neonatal Lupus (NL) is a rare syndrome caused by placental transfer of maternal anti-SSA/Ro and anti-La/SSB autoantibodies to the fetus. The rarity of this condition requires the establishment of multidisciplinary registries in order to improve our knowledge.

Method: Inclusion criteria in this retrospective study were the maternal confirmed positivity for anti-SSA/Ro and/or anti-SSB/La antibodies, and the presence of II or III degree congenital heart block (CHB) in utero or neonatal period (up to 27 days after birth).

Result: Eighty-nine cases of CHB were observed in 85 women with 88 pregnancies that occurred between 1969 and 2017. CHB was mostly detected in utero (84 cases, 94.2%), while five cases were observed in the neonatal period. A permanent pacemaker was implanted in 51 of 73 children born alive (69.8), whereas global mortality rate was 25.8% (23 cases): 16 in utero, five perinatal, and two during childhood. By univariate analysis, factors associated with fetal death were pleural effusion (p = 0.005, OR > 100; CI 95% 2.88->100 and hydrops (p = 0.003, OR = 14.09; CI 95% 2.01–122). Fluorinated steroids (FS) were administered in 71.4% pregnancies, and its use was not associated with better survival. Some centers treated all cases with fluorinated steroids and some centers did not treat any case. CHB was initially incomplete in 24 fetuses, and of them five cases of II degree block reverted to a lower degree block after treatments. Recurrence rate in subsequent pregnancies was 17.6% (3 out of 17). A prophylactic treatment was introduced in 10 of these 16 subsequent (58.8%) pregnancies, mostly with FS or high dose intravenous immunoglobulins.

Conclusion: This is the first report from the Italian Registry of neonatal lupus/CHB. The live birth rate was nearly 80%, with nearly two thirds of the children requiring the implantation of a pacemaker. The management of fetuses diagnosed with CHB was heterogeneous across Italian Centers. The registry at present is mainly rheumatological, but involvement of pediatric cardiologists and gynecologists is planned.

High maternal expression of SIGLEC1 on monocytes as a surrogate marker of a type I interferon signature is a risk factor for the development of autoimmune congenital heart block

Objectives

Autoimmune congenital heart block (CHB) is associated with placental transcytosis of maternal autoantibodies directed against Ro/SS-A and La/SS-B. However, only about 2% of children born to mothers with the respective antibodies are affected, indicating that further risk factors exist, which are not yet fully understood. In this study, we investigated whether a maternal type I interferon (IFN) signature represents a risk factor for the development of CHB.

Methods

Blood samples, clinical data and serological parameters from 9 women with CHB pregnancies, 14 pregnant women with antibodies against Ro/SS-A but without a CHB complication and another 30 healthy pregnant women as controls were studied. SIGLEC1 expression was measured by flow cytometry and was correlated to plasma IFN-α levels measured by ELISA, and IFN-γ-induced protein 10 (IP-10) levels measured by Bio-Plex technique.

Results

Mothers of affected children had a significantly higher expression of SIGLEC1 (p=0.0034) and IFN-α (p=0.014), but not of IP-10 (p=0.14, all MWU) compared to mothers of unaffected children. SIGLEC1 and IFN-α expression were reduced by hydroxychloroquine and oral glucocorticoids.

Conclusions

High expression of SIGLEC1 in pregnant women with autoantibodies against Ro/SS-A indicates an enhanced risk for CHB development, and these women may benefit especially from IFN-α directed therapy, for example with hydroxychloroquine.

Autoimmune congenital heart block: complex and unusual situations

Autoimmune congenital heart block (ACHB) is an immune-mediated cardiac disease included among the manifestations collectively referred to as neonatal lupus. The placental transference of maternal Ro/La autoantibodies may damage the conduction tissues during fetal development leading to blocking of signal conduction at the atrioventricular (AV) node in an otherwise structurally normal heart. Irreversible complete AV block is the main cardiac manifestation of ACHB, but some babies may develop endocardial fibroelastosis, valvular insufficiency, and/or frank cardiomyopathies with significantly reduced cardiac function requiring transplant. The severity of ACHB is illustrated by a global mortality rate of 20% and pacemaker rates of at least 64%, often within the first year of life. This review analyses the main complex and/or unusual clinical situations associated with ACHB, including unusual maternal immunological profiles, infrequent maternal autoimmune diseases, cardiac damage unrelated to AV block, fetal invasive management, late complications after birth, risk of congenital heart block (CHB) in ovodonation and in vitro fertilization techniques, the role of maternal features other than autoimmunity, the influence of the birth order or the risk of CHB in twins and triplets.

Congenital and childhood atrioventricular blocks: pathophysiology and contemporary management

Atrioventricular block is classified as congenital if diagnosed in utero, at birth, or within the first month of life. The pathophysiological process is believed to be due to immune-mediated injury of the conduction system, which occurs as a result of transplacental passage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood atrioventricular block is therefore diagnosed between the first month and the 18th year of life. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited progressive cardiac conduction disorders. Indications and techniques of cardiac pacing have also evolved to allow safe permanent cardiac pacing in almost all patients, including those with structural heart abnormalities.

CONCLUSION

Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current understanding of the pathogenetic mechanisms, clinical course, and optimal management of congenital and childhood AV block.

WHAT IS KNOWN

• Prevalence of congenital heart block of 1 per 15,000 to 20,000 live births. AV block is defined as congenital if diagnosed in utero, at birth, or within the first month of life, whereas childhood AV block is diagnosed between the first month and the 18th year of life. As a result of several different etiologies, congenital and childhood atrioventricular block may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Cardiac pacing is indicated in symptomatic patients and has several prophylactic indications in asymptomatic patients to prevent sudden death. • Autoimmune, congenital AV block is associated with a high neonatal mortality rate and development of dilated cardiomyopathy in 5 to 30 % cases. What is New: • Several genes including SCN5A have been implicated in autosomal dominant forms of familial progressive cardiac conduction disorders. • Leadless pacemaker technology and gene therapy for biological pacing are promising research fields. In utero percutaneous pacing appears to be at high risk and needs further development before it can be adopted into routine clinical practice. Cardiac resynchronization therapy is of proven value in case of pacing-induced cardiomyopathy.

Evaluation and management of bradycardia in neonates and children

Heart rate is commonly used in pediatric early warning scores. Age-related changes in the anatomy and physiology of infants and children produce normal ranges for electrocardiogram features that differ from adults and vary with age. Bradycardia is defined as a heart rate below the lowest normal value for age. Pediatric bradycardia most commonly manifests as sinus bradycardia, junctional bradycardia, or atrioventricular block. As a result of several different etiologies, it may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited sinus node dysfunction or progressive cardiac conduction disorders. Management and eventual prognosis of bradycardia in the young are entirely dependent upon the underlying cause. Reasons to intervene for bradycardia are the association of related symptoms and/or the downstream risk of heart failure or pause-dependent tachyarrhythmia. The simplest aspect of severe bradycardia management is reflected in the Pediatric and Advanced Life Support (PALS) guidelines.

CONCLUSION

Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current practice for evaluation and management of bradycardia in neonates and children.

WHAT IS KNOWN

Bradycardia is defined as a heart rate below the lowest normal value for age. Age related changes in the anatomy and physiology of infants and children produce normal ranges for electrocardiogram features that differ from adults and vary with age. Pediatric bradycardia most commonly manifests as sinus bradycardia, junctional bradycardia, or atrioventricular block.

WHAT IS NEW

Management and eventual prognosis of bradycardia in the young are entirely dependent upon the underlying cause. Bradycardia may occur in a structurally normal heart or in association with congenital heart disease. Genetic variants in multiple genes have been described. Reasons to intervene for bradycardia are the association of related symptoms and/or the downstream risk of heart failure or pause-dependent tachyarrhythmia. Early diagnosis and appropriate management are critical in order to prevent sudden death.

Case report and literature review. Prenatally Detected Non-Immune Atrioventricular Block and Maternal Arrhythmia - Case Presentation and Literature Review

Our clinical report describes a rare finding of a prenatally-detected congenital atrioventricular (AVB) block without associated maternal antibodies, which progressed from 1st/2nd degree AVB to complete heart block during second half of pregnancy. Obstetrical ultrasound at 12th week did not reveal any abnormalities and prenatal echocardiography (due to VSD in afamily member) at the 18th week of gestation detected 1st degree block, then bigeminy and bradycardia. Transplacental treatment with B-2-mimetics was introduced. The delivery was organized in a tertiary center and a pacemaker for the newborn baby was secured and implanted in 15th day of life. Currently the boy`s condition is good and stable. Before therapy with B-2-mimetics the mother underwent echocardiography and ECG which revealed clinically silent structural and conduction heart abnormalities. Literature findings suggest that parents of children with non-immune congenital or childhood AVB are more likely to carry clinically silent conduction abnormalities than general population. Given the corresponding findings in the mother and her son, they should be good candidates for genetic testing.

Isolated Complete Heart Block in the Fetus

Isolated congenital complete heart block (CCHB) is a rare disease with significant associated morbidity and mortality. A diagnosis is often made in fetal life, but data regarding long-term outcomes are limited, and fetal therapy to improve prognosis is controversial. In our institution, 85 fetuses were diagnosed with CCHB from 1981 to 2013 in 80 mothers. There were 37 anti-Ro-positive pregnancies, 36 both anti-Ro and anti-La positive, 10 antibody negative, and 2 of unknown antibody status. Antenatal treatments were given in 14 fetuses, with 8 given fluorinated steroids, 4 beta sympathomimetics, and both in 2. Of the original 85, 74 babies survived to delivery. Fetal hydrops was the only risk factor found to be significantly associated with intrauterine death (p <0.001). Four babies died before pacemaker implantation, 56 have had pacemakers implanted, and 14 are pacemaker free. The Kaplan-Meier estimate for median time to pacemaker implantation was 2.6 years, with 15 implanted in the neonatal period. There have been 14 postnatal deaths, with a Kaplan-Meier estimate of survival at 30 years of 76.8% (95% confidence interval 65% to 90%). Dilated cardiomyopathy was uncommon, occurring in 6 patients. Prematurity and hydrops were associated with increased postnatal mortality (p = 0.02 and 0.005, respectively). In conclusion, we present the largest single-unit experience of prenatally diagnosed CCHB in the published literature. Our cohort was conservatively managed, with survival similar to those previously published. These data offer insight into the long-term natural history of CCHB.

The clinical spectrum of autoimmune congenital heart block

Autoimmune congenital heart block (CHB) is an immune-mediated acquired disease that is associated with the placental transference of maternal antibodies specific for Ro and La autoantigens. The disease develops in a fetal heart without anatomical abnormalities that could otherwise explain the block, and which is usually diagnosed in utero, but also at birth or within the neonatal period. Autoantibody-mediated damage of fetal conduction tissues causes inflammation and fibrosis and leads to blockage of signal conduction at the atrioventricular (AV) node. Irreversible complete AV block is the principal cardiac manifestation of CHB, although some babies might develop other severe cardiac complications, such as endocardial fibroelastosis or valvular insufficiency, even in the absence of cardiac block. In this Review, we discuss the epidemiology, classification and management of women whose pregnancies are affected by autoimmune CHB, with a particular focus on the autoantibodies associated with autoimmune CHB and how we should test for these antibodies and diagnose this disease. Without confirmed effective preventive or therapeutic strategies and further research on the aetiopathogenic mechanisms, autoimmune CHB will remain a severe life-threatening disorder.

Effect of dual-chamber pacemaker implantation on aortic dilatation in patients with congenital heart block

Ascending aortic dilatation (AoD) in patients with structurally normal hearts and congenital heart block (CHB) has been previously described. The cause and management of AoD are yet to be determined. The aim of this study was to test the hypothesis that AoD in children with CHB regresses after the implantation of cardiac dual-chamber pacemakers (PMs). The secondary hypothesis was an association between the presence of maternal antibodies (SS-A or SS-B) and the degree of aortic dilatation. Clinical data with echocardiographic correlates of patients with CHB followed at a single institution were retrospectively reviewed. Comparison of the target structures diameter was based on 3 different z-score equations, with AoD defined as a z score >2. Inclusion criteria were CHB diagnosis by 12-lead electrocardiography or Holter recording and benefit from a permanent dual-chamber PM. Excluded were patients with incomplete echocardiographic measurements, those with major structural heart defects, and those with syndromes or diseases known to be associated with AoD. There were 17 patients, diagnosed at a median age of 6 months (interquartile range 0 to 47.8). Maternal antibodies were positive in 6 patients and negative in 11. All patients underwent PM implantation at a median age of 4.5 years (interquartile range 1.4 to 7.9). AoD (z score >2.0 according to 3 different equations) was present in 35% to 59% of patients. There was a significant reduction of mean ascending aortic z score in patients with AoD from 4.66 to 3.67 (p = 0.06), from 4.82 to 2.95 (p = 0.002), and from 6.07 to 3.39 (p = 0.006) according to the various z-score equations. Most patients with positive serology had AoD, without reaching statistical significance. In conclusion, AoD is associated with CHB, more likely in infants exposed to maternal antibodies. AoD decreases after the implantation of a PM. This is probably related to the regularization of stroke volume.

Late development of complete atrioventricular block may be immune mediated and congenital in origin

AIM

To investigate the correlation between maternal autoantibodies and age at diagnosis of isolated complete atrioventricular (AV) block (CAVB) and to study signs of late progression of foetal immune-mediated insults in cases of postnatally diagnosed CAVB.

METHODS

Patients with CAVB (n = 190) identified in a population-based manner were included. Maternal autoantibody profile was correlated with age at CAVB diagnosis. A structured review of medical records was performed if a late CAVB diagnosis (>27 days post-partum) was associated with a sero-positive mother.

RESULTS

Maternal Ro/La autoantibodies were observed in 88% of cases with a congenital diagnosis. Thirteen cases with a sero-positive mother and late CAVB diagnosis were found (age-range: 4 months-43 years). In two cases, CAVB was diagnosed in conjunction with infections, one case had a family history of cardiomyopathy and two cases had nontypical clinical presentations, indicating alternative pathogenetic mechanisms. In the remaining eight cases, no likely factors inducing CAVB, other than maternal autoantibodies, could be identified.

CONCLUSION

Our observations support the hypothesis that late progression to CAVB can be the result of an immune-mediated pathogenetic mechanism during foetal life. An autoantibody-associated diagnosis after the neonatal period is therefore possible, and testing of maternal serology at the time of diagnosis is recommended.

Parental electrocardiographic screening identifies a high degree of inheritance for congenital and childhood nonimmune isolated atrioventricular block

BACKGROUND

The origin of congenital or childhood nonimmune isolated atrioventricular (AV) block remains unknown. We hypothesized that this conduction abnormality in the young may be a heritable disease.

METHODS AND RESULTS

A multicenter retrospective study (13 French referral centers, from 1980-2009) included 141 children with AV block diagnosed in utero, at birth, or before 15 years of age without structural heart abnormalities and without maternal antibodies. Parents and matched control subjects were investigated for family history and for ECG screening. In parents, a family history of sudden death or progressive cardiac conduction defect was found in 1.4% and 11.1%, respectively. Screening ECGs from 130 parents (mean age 42.0 ± 6.8 years, 57 couples) were compared with those of 130 matched healthy control subjects. All parents were asymptomatic and in sinus rhythm, except for 1 with undetected complete AV block. Conduction abnormalities were more frequent in parents than in control subjects, found in 50.8% versus 4.6%, respectively (P<0.001). A long PR interval was found in 18.5% of the parents but never in control subjects (P<0.0001). Complete or incomplete right bundle-branch block was observed in 39.2% of the parents and 1.5% of the control subjects (P<0.0001). Complete or incomplete left bundle-branch block was found in 15.4% of the parents and 3.1% of the control subjects (P<0.0006). Estimated heritability for isolated conduction disturbances was 91% (95% confidence interval, 80%-100%). SCN5A mutation screening identified 2 mutations in 2 patients among 97 children.

CONCLUSIONS

ECG screening in parents of children affected by idiopathic AV block revealed a high prevalence of conduction abnormalities. These results support the hypothesis of an inheritable trait in congenital and childhood nonimmune isolated AV block.

Congenital heart block: evidence for a pathogenic role of maternal autoantibodies

During pregnancy in autoimmune conditions, maternal autoantibodies are transported across the placenta and may affect the developing fetus. Congenital heart block (CHB) is known to associate with the presence of anti-Ro/SSA and anti-La/SSB antibodies in the mother and is characterized by a block in signal conduction at the atrioventricular (AV) node. The mortality rate of affected infants is 15% to 30%, and most live-born children require lifelong pacemaker implantation. Despite a well-recognized association with maternal anti-Ro/La antibodies, CHB develops in only 1% to 2% of anti-Ro-positive pregnancies, indicating that other factors are important for establishment of the block. The molecular mechanisms leading to complete AV block are still unclear, and the existing hypotheses fail to explain all aspects of CHB in one comprehensive model. In this review, we discuss the different specificities of maternal autoantibodies that have been implicated in CHB as well as the molecular mechanisms that have been suggested to operate, focusing on the evidence supporting a direct pathogenic role of maternal antibodies. Autoantibodies targeting the 52-kDa component of the Ro antigen remain the antibodies most closely associated with CHB. In vitro experiments and animal models of CHB also point to a major role for anti-Ro52 antibodies in CHB pathogenesis and suggest that these antibodies may directly affect calcium regulation in the fetal heart, leading to disturbances in signal conduction or electrogenesis or both. In addition, maternal antibody deposits are found in the heart of fetuses dying of CHB and are thought to contribute to an inflammatory reaction that eventually induces fibrosis and calcification of the AV node, leading to a complete block. Considering that CHB has a recurrence rate of 12% to 20% despite persisting maternal autoantibodies, it has long been clear that maternal autoantibodies are not sufficient for the establishment of a complete CHB, and efforts have been made to identify additional risk factors for this disorder. Therefore, recent studies looking at the influence of genetic and environmental factors will also be discussed.

Cardiac manifestations of neonatal lupus: a review of autoantibody-associated congenital heart block and its impact in an adult population

Within the last decade the prevalence of adult patients living with congenital heart disease equals that seen in children. This expanding population poses a challenge to clinical cardiologists who will be caring for patients with the clinical manifestations of this condition. Neonatal lupus is a model of passively acquired autoimmunity and is responsible for the majority of clinical cases of congenital heart block (CHB). This review will focus on the presentation, pathophysiology, and the long-term follow-up of CHB associated with neonatal lupus, and discuss important diagnostic tests, familial implications, and pacemaker issues associated with the care of an adult with CHB.

Exercise capacity in children with isolated congenital complete atrioventricular block: does pacing make a difference?

The management of patients with isolated congenital complete atrioventricular block (CCAVB) has changed during the last decades. The current policy is to pace the majority of patients based on a variety of criteria, among which is limited exercise capacity. Data regarding exercise capacity in this population stems from previous publications reporting small case series of unpaced patients. Therefore, we have investigated the exercise capacity of a group of contemporary children with CCAVB. Sixteen children (mean age 11.5 ± 4; seven boys, nine girls) with CCAVB were tested. In 13 patients, a median number of three pacemakers were implanted, whereas in three patients no pacemaker was given. All patients had an echocardiogram and completed a cardiopulmonary cycle exercise test. Exercise parameters were determined and compared with reference values obtained from healthy Dutch peers. The peak oxygen uptake/body mass was reduced to 34.4 ± 9.5 ml kg(-1) min(-1) (79 ± 24% of predicted) and the ventilatory threshold was reduced to 52 ± 17% of peak oxygen uptake (78 ± 21% of predicted), whereas the peak work load/body mass was 2.8 ± 0.6 W/kg (91 ± 24% of predicted), which was similar to controls. Importantly, 25% of the paced patients showed upper rate restriction by the pacemaker. In conclusion, children with CCAVB show a reduced peak oxygen uptake and ventilatory threshold, whereas they show normal peak work rates. This indicates that they generate more energy during exercise from anaerobic energy sources. Paced children with CCAVB do not perform better than unpaced children.

Characteristics and long-term outcome of non-immune isolated atrioventricular block diagnosed in utero or early childhood: a multicentre study

AIMS

The natural history of congenital or childhood non-immune, isolated atrioventricular (AV) block is poorly defined.

METHODS AND RESULTS

We retrospectively studied 141 children with isolated, non-immune AV block diagnosed in utero, or up to 15 years of age, at 13 French medical centres, between 1980 and 2009. Patients with structural heart disease or maternal antibodies were excluded. Atrioventricular block was asymptomatic in 119 (84.4%) and complete in 100 (70.9%) patients. There was progression to complete AV block in 29/41 (70.7%) patients with incomplete AV block over 2.8 ± 3.4 years (1-155 months), but all patients with incomplete AV block may not have been included in the study. Narrow QRS complex was present in 18 of 26 patients (69.2%) with congenital, and 106 of 115 (92.2%) with childhood AV block. Pacemakers were implanted in 112 children (79.4%), during the first year of life in 18 (16.1%) and before 10 years of age in 90 (80.4%). The mean interval between diagnosis of AV block and pacemaker implants was 2.6 ± 3.9 years (0-300 months). The pacing indication was prophylactic in 70 children (62.5%). During a mean follow-up of 11.6 ± 6.7 years (1-32 years), no patient died or developed dilated cardiomyopathy (DCM). The long-term follow-up was uncomplicated in 127 children (90.1%).

CONCLUSION

In this large multicentre study, the long-term outcome of congenital or childhood non-immune, isolated AV block was favourable, regardless of the patient's age at the time of diagnosis. No patient died or developed DCM, and pacemaker-related complications were few.

Pregnancy outcomes in patients with autoimmune diseases and anti-Ro/SSA antibodies

Anti-Ro/SSA antibodies are associated with neonatal lupus (congenital heart block (CHB), neonatal transient skin rash, hematological and hepatic abnormalities), but do not negatively affects other gestational outcomes, and the general outcome of these pregnancies is now good, when followed by experienced multidisciplinary teams. The prevalence of CHB, defined as an atrioventricular block diagnosed in utero, at birth, or within the neonatal period (0-27 days after birth), in the offspring of an anti-Ro/SSA-positive women is 1-2%, of neonatal lupus rash around 10-20%, while laboratory abnormalities in asymptomatic babies can be detected in up to 27% of cases. The risk of recurrence of CHB is ten times higher. Most of the mothers are asymptomatic at delivery and are identified only by the birth of an affected child. Half of these asymptomatic women develop symptoms of a rheumatic disease, most commonly arthralgias and xerophtalmia, but few develop lupus nephritis. A standard therapy for CHB is still matter of investigation, although fluorinated corticosteroids have been reported to be effective for associated cardiomyopathy. Serial echocardiograms and obstetric sonograms, performed at least every 1-2 weeks starting from the 16th week of gestational age, are recommended in anti-Ro/SSA-positive pregnant women to detect early fetal abnormalities that might be a target of preventive therapy.

Arrhythmias presenting in neonatal lupus

Perfusion of human foetal heart with anti-Ro/SSA antibodies induces transient heart block. Anti-Ro/SSA antibodies may cross-react with T- and L-type calcium channels, and anti-p200 antibodies may cause calcium to accumulate in rat heart cells. These actions may explain a direct electrophysiological effect of these antibodies. Congenital complete heart block is the more severe manifestation of so-called "Neonatal Lupus". In clinical practice, it is important to distinguish in utero complete versus incomplete atrioventricular (AV) block, as complete AV block to date is irreversible, while incomplete AV block has been shown to be potentially reversible after fluorinated steroid therapy. Another issue is the definition of congenital AV block, as cardiologists have considered congenital blocks detected months or years after birth. We propose as congenital blocks detected in utero or within the neonatal period (0-27 days after birth). The possible detection of first degree AV block in utero, with different techniques, might be a promising tool to assess the effects of these antibodies. Other arrhythmias have been described in NL or have been linked to anti-Ro/SSA antibodies: first degree AV block, in utero and after birth, second degree (i.e. incomplete block), sinus bradycardia and QT prolongation, both in infants and in adults, ventricular arrhythmias (in adults). Overall, these arrhythmias have not a clinical relevance, but are important for research purposes.

Congenital heart block not associated with anti-Ro/La antibodies: comparison with anti-Ro/La-positive cases

OBJECTIVE

To study anti-Ro/La-negative congenital heart block (CHB).

METHODS

Forty-five fetuses with CHB were evaluated by analysis of anti-Ro/La antibodies using sensitive laboratory methods.

RESULTS

There were 9 cases of anti-Ro/La-negative CHB; 3 died (33.3%). Only 3 (33.3%) were complete in utero and 5 (55.5%) were unstable. No specific etiology was diagnosed. Six infants (66.6%) were given pacemakers. There were 36 cases of anti-Ro/La-positive CHB. All except 2 infants (94.4%) had complete atrioventricular block in utero. Ten died (27.8%), one (2.7%) developed severe dilated cardiomyopathy, and 26 (72.2%) were given pacemakers.

CONCLUSION

Nine of the 45 consecutive CHB cases (20%) were anti-Ro/La-negative with no known cause. They were less stable and complete than the anti-Ro/La positive cases.

[Fetal ultrasonography and Doppler in isolated congenital heart block]

Isolated congenital heart block is linked to transplacental passage of maternal anti-SSA/Ro and/or anti-SSB/La antibodies that may be related to a connective tissue disease. Ultrasonography and Doppler are essential to screen fetus at risk. They allow the diagnosis of first- and second-degree blocks which are probably preliminary stages in conducting tissue's injury. In these situations, a maternal treatment by fluorinated steroids can be proposed because of its possible effect on partial blocks. However, these early signs of nodal injury can be lacking: some fetus present a complete heart block without previously detected less advanced block. Moreover, the significance of first-degree block is unclear since it could reverse spontaneously. Other markers of nodal injury would be valuable. In case of complete congenital heart block, ultrasonography is useful to detect congestive heart failure and help the obstetrical management when unfavorable prognostic signs occur.

Presentation and prognosis of complete atrioventricular block in childhood, according to maternal antibody status

OBJECTIVES

We sought to determine whether the presentation and prognosis of children with complete atrioventricular block (CAVB) were related to maternal antibody status.

BACKGROUND

Comparative studies related to the presence or absence of maternal antibodies anti-SSB/La and anti-SSA/Ro are lacking in children with isolated complete CAVB.

METHODS

From 1980 to 2004, we screened for maternal antibodies in 111 children <15 years old with CAVB. According to the presence (Ab+) or absence (Ab-) of antibodies, 2 groups of patients were retrospectively compared.

RESULTS

The study group included 56 Ab+ and 55 Ab- patients with equal gender distribution. A total of 96% Ab+ patients were diagnosed in utero or within the first month, compared with 24% Ab- patients. Progression from incomplete to complete block was shown in 23 Ab- and 2 Ab+ patients. Echocardiography showed normal heart structures in Ab- patients, but 8 Ab+ patients had ostium secundum or ductus arteriosus. Pacemaker implantation was performed in 105 patients, and age at implantation was younger in the Ab+ group. At follow-up (age 9.7 +/- 6 years), all Ab- patients were alive with normal left ventricular function; dilated cardiomyopathy was diagnosed at diagnosis or during follow-up in 16 Ab+ patients, and 6 of 16 have died.

CONCLUSIONS

Patients with antibody-mediated CAVB were diagnosed and underwent pacing earlier in life and had a more severe prognosis than Ab- patients because of a high risk of dilated cardiomyopathy. The absence of antibody suggests a different pathologic mechanism than autoimmunity, and the term congenital may be not appropriate in these cases.

Identification and management of fetuses at risk for, or affected by, congenital heart block associated with autoantibodies to SSA (Ro), SSB (La), or an HsEg5-like autoantigen

The congenital heart block (CHB), diagnosed in structurally normal hearts, is strongly associated with, if not caused by, maternal SSA/SSB antibodies (Abs). It develops between 16 and 24 weeks' gestation, coincidentally with the increased transplacental IgG passage, and a window of unique cardiac vulnerability. Less is known about rare CHB cases in which neither cardiac malformations nor SSA/SSB Abs are detectable. We report on four pregnant women: patient 1 at high CHB risk (owing to Sjögren's syndrome (SS) and recurrent pregnancy losses), and patients 2-4 with already established CHB (aggravated by hydrops in patient 2). Abs were found directed to SSA/SSB (patients 1-3) or to an HsEg5-like autoantigen instead (patient 4). During preventive immunoadsorption (IA) from week 19 throughout (patient 1), or therapeutic IA (plus dexamethasone), commenced at week 25 (patient 2), SSA Ab levels decreased per session by 47+/-7 or 80+/-16%, respectively, and hydropic changes resolved. Patient 1 delivered a healthy boy, while patients 2-4 gave birth to CHB-affected children at need for permanent pacing. The irreversibility of complete CHB may justify (a) early ANA screening in all pregnancies (thereby also considering specificities as anti-HsEg5), and (b) preventive immmunoadsorption in high-risk pregnancies (before/during the critical cardiac development phase). This implies controversy, because factors converting risk to disease (in only approximately 2%) are unknown, and prospective randomized treatment studies are not available, given the rarity of CHB.

Is Isolated Congenital Heart Block Associated to Neonatal Lupus Requiring Pacemaker A Distinct Cardiac Syndrome?

Isolated congenital heart block (ICHB) is frequently associated with neonatal lupus syndrome (NLS). Therefore few data are available regarding the long-term cardiac outcome of newborns with ICHB and the pathogenic mechanisms are not yet defined. In order to compare demographic features and cardiological outcome of patients with ICHB submitted to pacemaker (PM) implantation with and without NLS, forty ICHB patients were evaluated pre- and post-PM implantation, by clinical, electrocardiogram, Holter Monitoring, treadmill test, and electrophysiological study. According to the presence of antibodies to 52 and 60 kDa Ro/SSA and La/SSB proteins in mother's sera, it was found that 60% (24/40) of patients had ICHB associated to NLS (ICHB/NL+). Twenty-three of 24 ICHB/NL+ patients were asymptomatic, and 16 (67%) were female (P = 0.013). The frequency of syncope, mitral insufficiency (MI), and congestive heart failure (CHF) was similar pre-PM implantation in both ICHB/NL+ and ICHB/NL- groups (P > 0.05). After PM implantation, MI and CHF were only observed in ICHB/NL+ patients, although not statistically significant. Interestingly, 67% of ICHB/NL+ were noticed before one year of age while only one fourth of ICHB/NL- was diagnosed in this period (P = 0.024). Almost half (46%) of ICHB/NL+ patients required PMs in the first 24 months of life, whereas only one in the ICHB/NL- received a PM at the same age (P = 0.02). In ICHB patients requiring PM implantation, the antibody-mediated lesion seems to be associated with an earlier onset and a more severe heart disease, in spite of the uniform criteria for PM indication.