Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela

Clinical practice guidance for Sjögren's syndrome in pediatric patients (2018) - summarized and updated

There are a considerable number of pediatric patients with Sjögren's syndrome (SS); however, SS is generally considered rare among children. Pediatric patients with SS report fewer sicca symptoms; therefore, many are under-diagnosed and cannot access appropriate medical management. Therefore, we propose a newly developed guidance for the diagnosis, treatment, and management of pediatric SS, including epidemiology, clinical features, and diagnostic examination methodology. The aim of this guidance was to standardize the medical care of pediatric SS in Japan, and we published the Japanese version by YODOSHA in 2018. This article is the English version, which is summarized and updated. This guidance will need to be revised in the near future as additional clinical data become available.

Epicardial implantation of a leadless pacemaker in a lamb model

BACKGROUND

Pacemaker used in small children typically consist of an abdominally placed generator and epicardially affixed leads, making such a system prone to lead dysfunction during growth. Aim of this study was to investigate the feasibility of epicardial pacing with a leadless pacemaker in a lamb model.

ANIMALS AND METHODS

Seventeen lambs underwent epicardial implantation of a Micra transcatheter pacing system (TPS) (Medtronic, Minneapolis, MN, USA) via left-lateral thoracotomy to the left ventricle (LV) surface (n = 11/17) and to the left atrial appendage (n = 6). Ventricular devices were fixated with the tines within the pericardium, whereas the tines of the atrial devices penetrated the myocardium of the left atrial appendage. After 31 weeks, animals were sacrificed and hearts were explanted for histological analysis.

RESULTS

Following implantation, median P/R amplitude was 4.25/5.5 mV while median pacing threshold was 1.1/1.9 V at 0.24 ms. After 31 weeks, median P/R amplitude was 3.3/4.2 mV. Median atrial pacing threshold was 0.5/0.24 ms. Eight of 10 ventricular pacemakers had lost capture at standard impulse width even at maximum impulse amplitude. On explantation, firm adhesion of the device to the thoracic wall and dislodgement of the electrode tip was found in those ventricular devices.

CONCLUSIONS

Firm fixation of the Micra electrode to the epicardial surface as applied to the atrial devices resulted in excellent electrical properties during midterm follow up. Pericardial fixation as in the ventricular devices was associated with loss of capture. Therefore, it is important to embed the tines in the myocardium and to choose an alternative implantation site allowing for safe fixation of the Micra TPS in a position perpendicular to ventricular epimyocardium.

Neonatal lupus with left bundle branch block and cardiomyopathy: a case report

Background

Cardiac manifestations of neonatal lupus include an array of structural and conduction abnormalities due to placental transference of maternal anti-SSA/Ro and anti-SSB/La autoantibodies. Late-onset neonatal lupus cardiomyopathies, occurring outside the neonatal period, is an infrequently reported manifestation with unknown pathophysiology and poorly defined treatment regimens. Due to the rarity of this condition, additional studies and case reports are required to better understand and manage late-onset neonatal lupus cardiomyopathies.

Case presentation

A 4-week-old female, born to a mother with known anti-SSA/Ro and anti-SSB/La autoantibodies, presents with classic cutaneous manifestations for neonatal lupus and is found to have left bundle branch block, severely dilated cardiomyopathy with an ejection fraction of 25%, and a thin echogenic dyskinetic ventricular septum. Weekly second trimester and 30-week fetal echocardiograms showed no signs of structural or conduction abnormalities. There were no histologic signs of inflammation on cardiac tissue biopsy. After a complicated hospital course, she was successfully treated with biventricular pacemaker, intravenous immunoglobulin, and plasmapheresis.

Conclusions

We present a case of late-onset neonatal lupus with severe dilated cardiomyopathy, a dyskinetic ventricular septum, and left bundle branch block. To our knowledge, the dyskinetic ventricular septum has never been reported and left bundle branch block is rarely reported in NL. This case further validates the need for long term cardiac follow up for patients born with NL, even if lacking cardiac manifestations in the peripartum period. We characterize a unique presentation of a rare clinical entity, highlighting the diagnostic challenges, and describe a successful treatment course.

A Broader Perspective on Anti-Ro Antibodies and Their Fetal Consequences-A Case Report and Literature Review

The presence of maternal Anti-Ro/Anti-La antibodies causes a passively acquired autoimmunity that may be associated with serious fetal complications. The classic example is the autoimmune-mediated congenital heart block (CHB) which is due in most cases to the transplacental passage of Anti-Ro/Anti-La antibodies. The exact mechanisms through which these pathologic events arise are linked to disturbances in calcium channels function, impairment of calcium homeostasis and ultimately apoptosis, inflammation and fibrosis. CHB still represents a challenging diagnosis and a source of debate regarding the best management. As the third-degree block is usually irreversible, the best strategy is risk awareness and prevention. Although CHB is a rare occurrence, it affects one in 20,000 live births, with a high overall mortality rate (up to 20%, with 70% of in utero deaths). There is also concern over the lifelong consequences, as most babies need a pacemaker. This review aims to offer, apart from the data needed for a better understanding of the issue at hand, a broader perspective of the specialists directly involved in managing this pathology: the rheumatologist, the maternal-fetal specialist and the cardiologist. To better illustrate the theoretical facts presented, we also include a representative clinical case.

Update on pregnancy complications in systemic lupus erythematosus

PURPOSE OF REVIEW

This review summarizes recent research in the field of systemic lupus erythematosus (SLE) and pregnancy with focus on clinical and biochemical predictors of adverse pregnancy outcomes (APOs), accumulating evidence for the safety and efficacy of hydroxychloroquine (HCQ) in pregnancy, and the importance of preconception counseling.

RECENT FINDINGS

Ongoing research from PROMISSE investigators (Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus) adds to the understanding of risk factors for APOs in SLE pregnancies, including aberrant complement activation, incomplete downregulation of lupus-associated transcription factors, and lower socioeconomic status. Evidence supporting numerous advantages for continuing HCQ in pregnancy, as well as support for low-dose aspirin in preeclampsia prevention is reviewed. Practice gaps exist among rheumatologists in ensuring effective contraception when women of childbearing age are undergoing therapy with potentially fetotoxic medications. The publication of organizational guidelines provides evidence-based recommendations on lupus pregnancy management.

SUMMARY

Outcomes of lupus pregnancies continue to improve with understanding of risk factors that predict APOs as well as improvements in disease management. Rheumatologists caring for women with SLE should be familiar with the most up-to-date research in order to optimize pregnancy outcomes in this population.

Left ventricular apical pacing in children: feasibility and long-term effect on ventricular function

AIMS

Left ventricular apical pacing (LVAP) has been reported to preserve left ventricular (LV) function in chronically paced children with complete atrioventricular block (CAVB). We sought to evaluate long-term feasibility of LVAP and the effect on LV mechanics and exercise capacity as compared to normal controls.

METHODS AND RESULTS

Thirty-six consecutive paediatric patients with CAVB and LVAP in the absence (N = 22) or presence of repaired structural heart disease (N = 14, systemic LV in all) and 25 age-matched normal controls were cross-sectionally studied after a median of 3.9 (interquartile range 2.1-6.8) years of pacing using echocardiography and exercise stress testing. Pacemaker implantation was uneventful and there was no death. Probability of the absence of pacemaker-related surgical revision (elective generator replacement excluded) was 89.0% at 5 years after implantation. Left ventricular apical pacing patients had lower maximum oxygen uptake (P = 0.009), no septal to lateral but significant apical to basal LV mechanical delay (P < 0.001) which correlated with decreased LV contraction efficiency (P = 0.001). Left ventricular ejection fraction and global longitudinal LV strain were, however, not different from controls. Results were similar in both the presence and absence of structural heart disease.

CONCLUSION

Left ventricular apical pacing is technically feasible with a low reintervention rate. Mechanical synchrony between LV septum and free wall is maintained at the price of an apical to basal mechanical delay associated with LV contraction inefficiency as compared to healthy controls. Global LV systolic function is, however, not negatively affected by LVAP.

Factors associated with long-term cardiac dysfunction in neonatal lupus

OBJECTIVES

Cardiac manifestations of neonatal lupus (NL) have been associated with significant morbidity and mortality; however, there is minimal information on long-term outcomes of affected individuals. This study was initiated to evaluate the presence of and the risk factors associated with cardiac dysfunction in NL after birth in multiple age groups to improve counselling, to further understand pathogenesis and to provide potential preventative strategies.

METHODS

Echocardiogram reports were evaluated in 239 individuals with cardiac NL: 143 from age 0-1 year, 176 from age >1-17 years and 64 from age >17 years. Logistic regression analyses evaluated associations of cardiac dysfunction at each age group with demographic, fetal and postnatal factors, using imputation to address missing data.

RESULTS

Cardiac dysfunction was identified in 22.4% at age 0-1 year, 14.8% at age >1-17 years and 28.1% at age >17 years. Dysfunction in various age groups was significantly associated with male sex, black race, lower fetal heart rates, fetal extranodal cardiac disease and length of time paced. In 106 children with echocardiograms at ages 0-1 year and >1-17 years, 43.8% with dysfunction at age 0-1 year were also affected at age >1-17 years, while the others reverted to normal. Of children without dysfunction at age 0-1 year, 8.9% developed new dysfunction between ages >1 and 17 years. Among 34 with echocardiograms at ages >1-17 years and >17 years, 6.5% with normal function at age >1-17 years developed dysfunction in adulthood.

CONCLUSIONS

Risk factors in fetal life can influence cardiac morbidity into adulthood.Although limited by a small number of cases, cardiac dysfunction in the first year often normalises by later childhood. New-onset dysfunction, although rare, can occur de novo after the first year.

Pacing in Patients with Congenital Heart Disease: When Is It Helpful and When Is It Harmful?

PURPOSE OF REVIEW

Pacing in pediatric and adult patients with congenital heart disease requires careful evaluation and thoughtful planning. Review of current guidelines with assessment of risk/benefit must be performed along with planning on a case-by-case basis in order to achieve maximal success and reduce risk in this specialized population of patients that is rapidly increasing in size.

RECENT FINDINGS

Guidelines for pacing in pediatric and congenital heart disease patients span many years. Most recent consensus and summary guidelines address pacing in adult patients with or without congenital heart disease. Pediatric recommendations from prior documents must be included in current decision-making. Pacing in pediatric and congenital heart disease patients is important therapy. Creation of an individualized plan of care with attention to risk/benefit decision-making regarding when and how to pace is critical in this population to maximize beneficial outcome.

Routine repeated echocardiographic monitoring of fetuses exposed to maternal anti-SSA antibodies: time to question the dogma

In around 1% of exposed pregnancies, anti-Ro/SSA and anti-La/SSB antibodies lead to congenital heart block, the main feature of neonatal lupus syndrome. As such, echocardiographic screening to detect congenital heart block, done every other week from 16 weeks to at least 24 weeks gestation, is widely recommended for anti-SSA-positive pregnant women. Such screening is now routinely done in many centres worldwide. In this Viewpoint, we call this dogma into question for several reasons. Even if congenital heart block is discovered (which is rare), the usefulness of treatment with fluorinated steroids has not been shown, whereas the associated side-effects are well known. The discovery of congenital heart block very early in the pregnancy does not modify obstetric management, and at least 500 ultrasounds are needed to find one case of congenital heart block, which would ultimately be found by other means. Finally, this screening strategy misses most cases of congenital heart block because most affected women are not known to have anti-SSA antibodies, and thus are not screened. Accordingly, except in the context of research protocols, which are certainly needed and are outside the scope of this Viewpoint, overturning the dogma of routine repeated screenings for congenital heart block could save money and health-care staff time and prevent maternal stress without substantial clinical consequences.

Autoimmune-mediated congenital heart block

Autoimmune-mediated congenital heart block (CHB) is a severe manifestation of neonatal lupus in which conduction tissues of the fetal heart are damaged. This occurs due to passive transference of maternal anti-SSA/Ro and anti-SSB/La autoantibodies and subsequent inflammation and fibrosis of the atrioventricular (AV) node. Notably, the disease manifests after the fetal heart has structurally developed, ruling out other anatomical abnormalities that could otherwise contribute to the block of conduction. Complete AV block is irreversible and the most common manifestation of CHB, although other cardiac complications such as endocardial fibroelastosis (EFE), dilated cardiomyopathy, and valvular insufficiency have been observed. In this review, we detail the classification, prevalence, pathogenesis, and clinical management recommendations for autoimmune 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.

Cardiomyopathy in Children: Classification and Diagnosis: A Scientific Statement From the American Heart Association

In this scientific statement from the American Heart Association, experts in the field of cardiomyopathy (heart muscle disease) in children address 2 issues: the most current understanding of the causes of cardiomyopathy in children and the optimal approaches to diagnosis cardiomyopathy in children. Cardiomyopathies result in some of the worst pediatric cardiology outcomes; nearly 40% of children who present with symptomatic cardiomyopathy undergo a heart transplantation or die within the first 2 years after diagnosis. The percentage of children with cardiomyopathy who underwent a heart transplantation has not declined over the past 10 years, and cardiomyopathy remains the leading cause of transplantation for children >1 year of age. Studies from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry have shown that causes are established in very few children with cardiomyopathy, yet genetic causes are likely to be present in most. The incidence of pediatric cardiomyopathy is ≈1 per 100 000 children. This is comparable to the incidence of such childhood cancers as lymphoma, Wilms tumor, and neuroblastoma. However, the published research and scientific conferences focused on pediatric cardiomyopathy are sparcer than for those cancers. The aim of the statement is to focus on the diagnosis and classification of cardiomyopathy. We anticipate that this report will help shape the future research priorities in this set of diseases to achieve earlier diagnosis, improved clinical outcomes, and better quality of life for these children and their families.

Discordant immune complete heart block and growth restriction in dichorionic twin pregnancy with permanent pacemaker implantation of an 1140 g neonate

Fetal atrioventricular block is a rare pathology, mostly due to placental transmission of maternal SSA/Ro and SSB/La antibodies, and can lead to severe fetal or neonatal outcomes. We report a case of dichorionic, diamniotic twin pregnancy, with maternal SSA/Ro antibodies. Isolated complete atrioventricular block was diagnosed at 23 weeks in one fetus (Twin A), while the second fetus (Twin B) remained in normal sinus rhythm. Severe asymmetric intrauterine growth restriction occurred in Twin A. Delivery was by caesarean section at 32 + 2 weeks. Neonatal permanent pacemaker was inserted on the first day after birth in 1140 g neonate. Discordant heart block in twin pregnancy has already been reported in a few dichorionic pregnancies, but the pathway of discordant disease expression remains unclear. Extraction decision is a dilemma between cardiac failure prevention and prematurity associated twin morbidity. This case shows a successful pacing in a very low birth weight neonate.

Comorbidity and long-term outcome in patients with congenital heart block and their siblings exposed to Ro/SSA autoantibodies in utero

OBJECTIVE

Congenital heart block (CHB) may develop in fetuses of Ro/SSA autoantibody-positive women. Given the rarity of CHB, information on comorbidity and complications later in life is difficult to systematically collect for large groups of patients. We therefore used nation-wide healthcare registers to investigate comorbidity and outcomes in patients with CHB and their siblings.

METHODS

Data from patients with CHB (n= 119) and their siblings (n= 128), all born to anti-Ro/SSA-positive mothers, and from matched healthy controls (n= 1,190) and their siblings (n= 1,071), were retrieved from the Swedish National Patient Register. Analyses were performed by Cox proportional hazard modelling.

RESULTS

Individuals with CHB had a significantly increased risk of cardiovascular comorbidity, with cardiomyopathy and/or heart failure observed in 20 (16.8%) patients versus 3 (0.3%) controls, yielding a HR of 70.0 (95% CI 20.8 to 235.4), and with a HR for cerebral infarction of 39.9 (95% CI 4.5 to 357.3). Patients with CHB also had a higher risk of infections. Pacemaker treatment was associated with a decreased risk of cerebral infarction but increased risks of cardiomyopathy/heart failure and infection. The risk of systemic connective tissue disorder was also increased in patients with CHB (HR 11.8, 95% CI 4.0 to 11.8), and both patients with CHB and their siblings had an increased risk to develop any of 15 common autoimmune conditions (HR 5.7, 95% CI 2.83 to 11.69 and 3.6, 95% CI 1.7 to 8.0, respectively).

CONCLUSIONS

The data indicate an increased risk of several cardiovascular, infectious and autoimmune diseases in patients with CHB, with the latter risk shared by their siblings.

Arrhythmia and/or Cardiomyopathy Related to Maternal Autoantibodies: Descriptive Analysis of a Series of 16 Cases From a Single Center

Objective: To describe the clinical characteristics of maternal autoantibody-mediated arrhythmia and/or cardiomyopathy, and to explore the therapeutic role of glucocorticoids in these diseases. Methods: This was a retrospective observational study of 2 fetuses and 14 children who presented with autoantibody-mediated arrhythmia and/or cardiomyopathy in our hospital from September 2010 to December 2018. Results: In total, 16 patients were identified, including 2 fetuses, and 14 children. One mother suffered from Sjogren's syndrome, two suffered from systemic lupus erythematosus (SLE), and the remaining 13 were asymptomatic carriers of autoantibodies. Two fetuses were diagnosed with complete congenital heart block (CHB) and had mean heart rates of 45 and 50 bpm. In the 14 surviving children, third-degree CHB was detected in 4 children, second- to third-degree CHB in 4, corrected QT interval (QTc) prolongation in 1, atrioventricular dissociation, and junctional ectopic tachycardia in 1, complete left bundle branch block (CLBBB) with dilated cardiomyopathy (DCM) in 3, and endocardial fibroelastosis (EFE) in 1. All of the 14 surviving babies received intravenous immunoglobulin and glucocorticoids. None of the children received pacemaker implantation. During the follow-up, one 3-month-old girl who had complete CHB, DCM, and Torsades de pointes almost recovered after the administration of prednisone for ~8 years. Three cases with complete CHB had no improvement after 3-5 years of follow-up. One case with EFE and three cases with CLBBB and DCM were in stable condition now. Children with QTc prolongation and junctional ectopic tachycardia returned to a regular rhythm. Conclusions: Autoantibody-mediated arrhythmias and/or cardiomyopathy are severe complications related to maternal autoantibodies, and the administration of steroid may be beneficial in reversing complete CHB.

The prevention, screening and treatment of congenital heart block from neonatal lupus: a survey of provider practices

Objective

To survey an international sample of providers to determine their current practices for the prevention, screening, and treatment of congenital heart block (CHB) due to maternal Ro/SSA antibodies.

Methods

A survey was designed by the organizing committee of the 9th International Conference of Reproduction, Pregnancy and Rheumatic Diseases. It was sent to attendants of the conference and authors of recent publications or abstracts at ACR 2012, 2013 or 2014 on rheumatic diseases and pregnancy.

Results

In anti-Ro/SSA positive women, 80% of 49 respondents recommended screening by serial fetal echocardiogram (ECHO), with most starting at week 16 (59%) and stopping at week 28 (25%), although the time to stop varied widely. For women without a prior infant with neonatal lupus, respondents recommend every other week (44%) or weekly (28%) fetal ECHOs. For women with a prior infant with neonatal lupus, 80% recommend weekly fetal ECHOs. To prevent CHB, HCQ was recommended by 67% of respondents and most would start pre-pregnancy (62%). Respondents were asked about medications to treat varying degrees of CHB in a 20-week pregnant, anti-Ro and La positive SLE patient. For first degree, respondents recommended starting dexamethasone (53%) or HCQ (43%). For second degree, respondents recommended starting dexamethasone (88%). For third degree, respondents recommended starting dexamethasone (55%) or IVIg (33%), although 27% would not start treatment.

Conclusion

Despite the absence of official guidelines, many physicians with a focus on pregnancy and rheumatic disease have developed similar patterns in the screening, prevention and treatment of CHB.

What endocardial right ventricular pacing site shows better contractility and synchrony in children and adolescents?

AIMS

Right ventricular (RV) apical (RVA) pacing can induce left ventricular (LV) dyssynchrony, remodeling, and dysfunction in children with complete atrioventricular block (CAVB). We compared the functional outcome of RVA with RV alternative pacing sites (RVAPS), including para-Hisian, septal, and outflow tract sites.

METHODS

This is a single-center, retrospective study. Data were collected before pacemaker implantation (transvenous leads), postoperatively, at 6 months, and at 1-2-3-4 years. Electrocardiogram evaluation included QRS duration, axis, QTc/JTc, and QTc dispersion. Echocardiographic evaluation included 2-D/3-D assessment of ventricular dimensions (Z-score of LV end-diastolic dimension), function (ejection fraction), and synchrony.

RESULTS

From 2009 to 2015, 55 patients with CAVB, aged 3-17 years, with or without other congenital heart defects, underwent RVAPS (30 patients, median age 11 years) or RVA (25 patients, median 12 years). All leads were positioned into the septum. Before implantation, no significant differences in parameters were observed, except for higher Z-score in RVAPS than in RVA. After implantation, at a median follow-up of 2.5 (range 1-6) years, the two groups showed no significant differences in LV dimensions, contractility, and synchrony. QRS intervals of RVAPS were significantly shorter than RVA. Clinical status was good and contractility/synchrony indexes were normal or adequate in all patients.

CONCLUSIONS

In pediatric patients, RVAPS and RVA showed no significant differences in LV dimensions, contractility, and synchrony. Preimplantation dilated patients showed LV reverse remodeling. RVAPS demonstrated shorter QRS intervals. Therefore, septal pacing sites, either RVA or RVAPS, seem to determine good contractility and synchrony at a mid-term follow-up.

A complicated multisystem flare of systemic lupus erythematosus during pregnancy

We report a case of systemic lupus erythematosus (SLE) in a young woman who became pregnant amid a severe flare. She continued to have active disease in the face of aggressive treatments complicated by several side effects of immunosuppressive drugs including recurrent sepsis and gestational diabetes. Her fetus was at risk for congenital heart block during the second and third trimesters. Despite an extremely guarded prognosis, she delivered a healthy baby girl. This case highlights the complexities of SLE management during pregnancy. We discuss the therapeutic options available in pregnancy, and highlight the importance of cross-specialty multidisciplinary care in these women.

Key Role of Pacing Site as Determinant Factor of Exercise Testing Performance in Pediatric Patients with Chronic Ventricular Pacing

Chronic right ventricular (RV) apical pacing has been associated with deterioration of functional capacity and chronotropic incompetence during exercise testing in children. The effects of alternative pacing site on exercise performance in pediatric population remain unknown. We evaluated the influence of ventricular pacing site on exercise capacity in pediatric patients with complete congenital atrioventricular block requiring permanent pacemaker therapy. Sixty-four children paced from RV apex (n = 26), RV midseptum (n = 15) and left ventricular (LV) apex (n = 23) were studied cross-sectionally. Treadmill exercise stress testing was performed according to modified Bruce protocol. LV apical pacing was associated with greater exercise capacity. In comparison with the other study groups, children with RV apical pacing showed significantly lower VO₂peak (37 ± 4.11; p = 0.003), O₂ pulse (8.78 ± 1.15; p = 0.006), metabolic equivalents (7 ± 0.15; p = 0.001) and exercise time (6 ± 3.28; p = 0.03). Worse values in terms of maximum heart rate (139 ± 8.83 bpm; p = 0.008) and chronotropic index (0.6 ± 0.08; p = 0.002) were detected in the RV apical pacing group although maximal effort (respiratory exchange ratio) did not differ among groups (p = 0.216). Pacing from RV apex (odds ratio 9.4; confidence interval 2.5-18.32; Wald 4.91; p = 0.0036) and low peak heart rate achieved (odds ratio 3.66; confidence interval 0.19-7.4; Wald 4.083; p = 0.015) predicted significantly decrease in exercise capacity. Duration of pacing, gender, VVIR mode, baseline heart rate and QRS duration had not significant impact on exercise capacity. The site of ventricular pacing has the major impact on exercise capacity in children requiring permanent pacing. Among the sites assessed, LV apex is related to the better exercise performance.

The development of pacing induced ventricular dysfunction is influenced by the underlying structural heart defect in children with congenital heart disease

Background

Right ventricular pacing can cause pacing-induced ventricular dysfunction (PIVD) correctable with biventricular pacing (BiVP). Factors associated with PIVD are poorly understood.

Methods

We reviewed children receiving epicardial dual-chamber pacemakers for complete heart block (CHB) after congenital heart disease (CHD) surgery. PIVD was defined as% fractional shortening <15% improving after BiVP.

Results

Between 2005 and 2014, 47 children <2 years developed CHB after CHD surgery. All had biventricular hearts and underwent epicardial dual chamber pacemaker implantation. Nine of the 47 (19%) developed PIVD. PIVD occurred in 0/10 with ventricular septal defect (VSD), 0/6 with tetralogy of Fallot, 2/6 with double outlet right ventricle, 2/6 with transposition and VSD, 3/9 with atrioventricular canal defect, 1/2 with mitral valve replacement; 1/3 with congenitally corrected TGA repair; and 0/3 with atrioventricular canal plus tetralogy of Fallot and 0/1 with subaortic membrane. QRS duration (QRSD) was 84–170 (median 135 ms) in the non PIVD group and 100–168 (median 124) ms in the PIVD group. Percentage fractional shortening (%FS) while paced was 16–46, median 30% in the non-PIVD group and 6–15 (median 11%) in the PIVD group.%FS post upgrade to BiVP (with an epicardial LV lead) in the 9 patients with PIVD was 23–33 (median 29%).

Conclusions

PIVD occurred in certain CHD but not others. Prolonged QRSD was not associated with PIVD. The predilection for RV pacing to result in PIVD in certain types of CHD needs further study.

Isolated congenital complete heart block in a five-year-old seronegative girl born to a woman seropositive for human immunodeficiency virus: a case report

Background

Congenital complete heart block is a life-threatening condition which is highly associated with autoimmune and connective tissue disorders. Presence of maternal autoantibodies for associated conditions increases the risk of delivering a child with congenital complete heart block, however, less than a half of all women with such antibodies are symptomatic even after delivery. Mortality rate is highest during the neonatal period (45 %) and about two-thirds of all cases will require permanent pacing at some point in their lives.

Case presentation

We report a case of isolated complete heart block in a 5-year-old HIV-free girl of African descent born to an HIV-infected woman with no prior history of autoimmune disorders. She was referred to us with chief complaints of recurrent syncopal attacks and effort intolerance since birth. A physical examination was unremarkable except for her being small for her age (body mass index 16.3 kg/m²) and bradycardia. Her vital signs were within acceptable range with the exception of her pulse rate, which ranged between 22 and 34 beats/minute. An echocardiogram revealed a sinus bradycardia, otherwise a structurally normal heart. An electrocardiogram showed atrioventricular dissociation in keeping with third-degree atrioventricular block. The child underwent a permanent epicardial pacemaker insertion and has been symptom-free following pacing.

Conclusions

Despite its infrequency and life-threatening potential, patients with congenital complete heart block have an excellent survival rate with timely diagnosis and intervention. An incidental detection of bradycardia in a fetus during routine obstetrical ultrasound examination should increase the index of suspicion for congenital complete heart block and warrant a screening for associated maternal autoantibodies.

Late Outcome and Predictors of Adverse Events Related to the Implantation of a Permanent Pacemaker in Patients with Isolated Congenital Atrioventricular Block

Isolated congenital atrioventricular block (ICAVB) is a rare, and pacemaker implantation is the only effective treatment. We sought to identify the predictive factors of adverse events related to pacemaker implantation in ICAVB. This is a cohort study of patients diagnosed with ICAVB who underwent pacemaker implantation from 1980 to 2014 in a single center. During the studied period, a total of 647 patients underwent implantation of their first permanent cardiac pacemaker before 30 years of age. Of these, only 62 (9.5 %) were diagnosed with ICAVB. This condition was diagnosed in utero in 15 (24.2 %) cases, 5 (8.1 %) in the neonatal period, 32 (51.6 %) during childhood, and 10 (16.1 %) during adolescence and young adulthood. The presence of autoantibodies (anti-Ro/SSA) was observed in 41 % of mothers who underwent serological evaluation. Age at the time of the initial pacemaker implant was 9.8 ± 9 years. During a mean follow-up time of 15 years, 1 (1.7 %) death occurred due to infectious endocarditis. Complications related to pacemaker implant were reported in 24 patients (38.7 %). The number of complications was significantly higher in the group with an epimyocardial implantation site (HR 6; CI 2.45-14.95). Ventricular dysfunction occurred in 6 (11.7 %) patients; however, we were not able to identify any predictors of it. Our results showed a low mortality rate after permanent therapy. However, these patients exhibited high morbidity related to the pacemaker system, and the epimyocardial implant site was an independent predictor of complications. Predictors of left ventricular dysfunction were not found in the present study.

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.

Neonatal outcome in patients with rheumatic disease

Rheumatic autoimmune diseases have a higher prevalence in women, particularly during their childbearing age. Due to improved management, an increasing number of patients plan and carry out one or more pregnancies. Therefore, a growing interest is being paid to the possible consequences of maternal disease and associated treatment on the fetus and newborn infant. If maternal disease is characterized by the presence of IgG isotype autoantibodies, these can cross the placenta with possible antibody-mediated damage to the fetus. This is typically the case of the so called neonatal lupus erythematosus (NLE); a similar mechanism has been shown in infants of patients with immune thrombocytopenic purpura (ITP) and, less frequently, in those from mothers with antiphospholipid syndrome (APS). Indeed, this last condition is often responsible for placental, rather than neonatal, pathology. In addition, immunosuppressive and other drugs administered to the mothers during pregnancy and lactation might affect the fetal and neonatal immune system development. Finally, mothers disease and/or treatment could be related to neuropsychological alteration reported in some of their children.

Pregnancy and autoimmune connective tissue diseases

Autoimmune connective tissue diseases predominantly affect women and often occur during the reproductive years. Thus, specialized issues in pregnancy planning and management are commonly encountered in this patient population. This chapter provides a current overview of pregnancy as a risk factor for onset of autoimmune disease, considerations related to the course of pregnancy in several autoimmune connective tissue diseases, and disease management and medication issues before pregnancy, during pregnancy, and in the postpartum period. A major theme that has emerged across these inflammatory diseases is that active maternal disease during pregnancy is associated with adverse pregnancy outcomes, and that maternal and fetal health can be optimized when conception is planned during times of inactive disease and through maintaining treatment regimens compatible with pregnancy.

Assessment of fluorinated steroids to avert progression and mortality in anti-SSA/Ro-associated cardiac injury limited to the fetal conduction system

OBJECTIVES

Extension of disease beyond the atrioventricular (AV) node is associated with increased mortality in cardiac neonatal lupus (NL). Treatment of isolated heart block with fluorinated steroids to prevent disease progression has been considered but published data are limited and discordant regarding efficacy. This study evaluated whether fluorinated steroids given to manage isolated advanced block prevented development of disease beyond the AV node and conferred a survival benefit.

METHODS

In this retrospective study of cases enrolled in the Research Registry for NL, inclusion was restricted to anti-SSA/Ro-exposed cases presenting with isolated advanced heart block in utero who either received fluorinated steroids within 1 week of detection (N=71) or no treatment (N=85). Outcomes evaluated were: development of endocardial fibroelastosis, dilated cardiomyopathy and/or hydrops fetalis; mortality and pacemaker implantation.

RESULTS

In Cox proportional hazards regression analyses, fluorinated steroids did not significantly prevent development of disease beyond the AV node (adjusted HR=0.90; 95% CI 0.43 to 1.85; p=0.77), reduce mortality (HR=1.63; 95% CI 0.43 to 6.14; p=0.47) or forestall/prevent pacemaker implantation (HR=0.87; 95% CI 0.57 to 1.33; p=0.53). No risk factors for development of disease beyond the AV node were identified.

CONCLUSIONS

These data do not provide evidence to support the use of fluorinated steroids to prevent disease progression or death in cases presenting with isolated heart block.

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.

Reassessing Risk Factors in Pediatric Patients With Pacemakers Implanted for Atrioventricular Block: The Impact of Nonsustained Ventricular Tachycardia

INTRODUCTION

In pediatric patients with pacemakers implanted for atrioventricular block (AVB), nonsustained ventricular tachycardia (NSVT) detected during routine surveillance is a finding of unknown significance. We sought to describe the incidence of NSVT and determine if there was an association between NSVT and adverse outcomes in these patients.

METHODS AND RESULTS

This is a single-center retrospective study of 136 patients (1971-2013) with pacemakers implanted for advanced and complete AVB.

EXCLUSION CRITERIA

structural heart disease, diagnoses of myocarditis, cardiomyopathy or channelopathy preceding AVB diagnosis, and sustained or polymorphic ventricular tachycardia (VT) as the first occurring arrhythmia after pacemaker implant. During median follow-up of 11.6 years (IQR 4.3 years, 17 years), 14 (10%) patients had NSVT. There were 6 (4.4%) deaths. Overall, Kaplan-Meier 20-year survival from time of implant was 93%. By univariate analysis, earlier mortality was associated with NSVT (P = 0.010), sustained left ventricular (LV) dysfunction (P = 0.004), maternal autoantibodies (P = 0.017), and acquired AVB (P = 0.049). By multivariate analysis, earlier mortality was associated with NSVT (HR: 5.39 [95% CI: 1.02-28.41]; P = 0.047) and sustained LV dysfunction (HR: 10.24 [95% CI: 1.83-57.32]; P = 0.008).

CONCLUSIONS

In children with pacemakers implanted for AVB, NSVT is not uncommon and may be associated with increased mortality. Persistent LV dysfunction may also be a potential factor associated with death. Closer follow-up should be considered in patients with these findings. Large, multicenter studies should be considered to confirm these findings and identify risk stratification methods for this unique patient population.

Left Atrial Inexcitability in Children With Congenital Lupus-Induced Complete Atrioventricular Block

Background

Congenital atrioventricular block is a well‐established immunologic complication of maternal systemic lupus erythematosus. We sought to further characterize the electrophysiological manifestations of maternal systemic lupus erythematosus on neonatal atria.

Methods and Results

Cases of isolated congenital atrioventricular block treated at our center over the past 41 years were identified. Data were extracted from clinical charts, pacemaker interrogations, ECGs, echocardiograms, and histopathological reports, when available. Of 31 patients with isolated congenital atrioventricular block, 18 were negative for maternal antibodies and had normal epicardial atrial sensing and pacing thresholds. In contrast, 12 of 13 patients with positive maternal antibodies had epicardial pacemakers, 5 (42%) of whom had left atrial (LA) inexcitability and/or atrial conduction delay. In 3 patients, the LA could not be captured despite high‐output pacing. The fourth patient had acutely successful LA appendage and left ventricular lead placement. At early follow‐up, an increased delay between the surface P‐wave and intracardiac atrial depolarization was observed, indicative of atrial conduction delay. The fifth patient exhibited LA lead dysfunction, with atrial under‐sensing and an increased capture threshold, 2 weeks after implantation. Biopsies of LA appendages performed in 2 patients showed no evidence of atrial fibrosis or loss of atrial myocytes.

Conclusions

Herein, we report previously undescribed yet prevalent electrophysiological ramifications of maternal systemic lupus erythematosus, which extend beyond congenital atrioventricular block to encompass alterations in LA conduction, including LA inexcitability. These manifestations can complicate epicardial pacemaker implantation in newborns. In the absence of histological evidence of extensive atrial fibrosis, immune‐mediated functional impairment of electrical activity is suspected.