Congenital and childhood atrioventricular blocks: pathophysiology and contemporary management

Molecular Mechanisms of Fetal and Neonatal Lupus: A Narrative Review of an Autoimmune Disease Transferal across the Placenta

This study, conducted by searching keywords such as "maternal lupus", "neonatal lupus", and "congenital heart block" in databases including PubMed and Scopus, provides a detailed narrative review on fetal and neonatal lupus. Autoantibodies like anti-Ro/SSA and anti-La/SSB may cross the placenta and cause complications in neonates, such as congenital heart block (CHB). Management options involve hydroxychloroquine, which is able to counteract some of the adverse events, although the drug needs to be used carefully because of its impact on the QTc interval. Advanced pacing strategies for neonates with CHB, especially in severe forms like hydrops, are also assessed. This review emphasizes the need for interdisciplinary care by rheumatologists, obstetricians, and pediatricians in order to achieve the best maternal and neonatal health in lupus pregnancies. This multidisciplinary approach seeks to improve the outcomes and management of the disease, decreasing the burden on mothers and their infants.

Subclinical maternal autoimmune disease leading to congenital high degree atrioventricular block: Case report and review of the literature

Maternal autoimmune disease is the most common cause of congenital heart block (CHB), a rare illness characterized by fibrosis and calcification of the fetal atrioventricular (AV) node due to maternal autoantibodies anti-SSA/Ro and anti-SSB/La. We report the full autopsy and clinical information on a female neonate with high degree AV block and calcification in the AV node, atrial approaches to the AV node, and both right and left bundle branches, born to a 27-year-old female with subclinical autoimmune disease.

The cardiac conduction system: History, development, and disease

The heart is the first organ to form during embryonic development, establishing the circulatory infrastructure necessary to sustain life and enable downstream organogenesis. Critical to the heart's function is its ability to initiate and propagate electrical impulses that allow for the coordinated contraction and relaxation of its chambers, and thus, the movement of blood and nutrients. Several specialized structures within the heart, collectively known as the cardiac conduction system (CCS), are responsible for this phenomenon. In this review, we discuss the discovery and scientific history of the mammalian cardiac conduction system as well as the key genes and transcription factors implicated in the formation of its major structures. We also describe known human diseases related to CCS development and explore existing challenges in the clinical context.

Late-Onset Dilated Cardiomyopathy in Auto Immune-Mediated Complete Congenital Heart Block: A Case Report

Complete congenital heart block (CHB), a rare and fatal bradyarrhythmia observed in children, carries significant mortality and morbidity. When congenital heart block occurs in isolation with a structurally normal heart, it prompts suspicion of an autoimmune etiology, wherein maternal antibodies are transmitted transplacentally, impacting the fetal conducting system. The manifestation of congenital complete atrioventricular block (CCAVB) can lead to complications such as dilated cardiomyopathies, arrhythmias, and fibroelastosis in certain cases. Notably, dilated cardiomyopathy is a significant prognostic factor in children diagnosed with congenital heart block. Pathological investigations have revealed the presence of antibodies, complements, and indicators of inflammation or fibrosis across the myocardium, emphasizing the shared molecular mechanisms between CCAVB and the development of dilated cardiomyopathy (DCM). This article presents the case of a one-year-old female child who presented with signs of dilated cardiomyopathy, later identified through retrospective evaluation as having autoimmune congenital heart block. The mother of the child was diagnosed with Sjogren's syndrome, characterized by positive anti-RO titers. Remarkably, the child remained asymptomatic for a year without the need for pacing intervention. The child's condition was successfully stabilized with appropriate treatment, and plans for pacemaker insertion will be considered once specific criteria are met. The onset of cardiomyopathy in a known case of CCAVB should serve as a crucial alert for prognostic considerations and the potential necessity for early-pacing intervention.

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.

Severe cardiac conduction disease associated with titin gene mutation

Heart block is rare in pediatrics with many possible causes. An association between complete heart block (CHB) and pathogenic titin (TTN) mutations have not been previously described. We report a 9-year-old female with history of leukodystrophy and family history of atrial fibrillation who presented with syncope and conduction abnormalities, including CHB. She underwent pacemaker implantation and genetic testing demonstrated a pathogenic TTN mutation likely responsible for her cardiac findings. Our case suggests an association between TTN mutations and conduction disease and emphasizes broadening gene testing in assessing these patients, especially when a family history is present.

Endocardial pacing compared to epicardial left ventricle pacing and right ventricle pacing: A single-center long-term experience in a pediatric population

BACKGROUND AND AIMS

Pediatric pacing is usually performed as epicardial pacing in small children in need of pacemaker therapy. Epicardial pacing compared with transvenous pacing for pediatric complete atrioventricular block (CAVB) has different strengths and weaknesses. The epicardial left ventricular wall position of the lead has been considered superior, in terms of contraction pattern, compared to a transvenous right ventricular stimulation. We aimed to compare QRS duration and cardiac function before and after the switch from epicardial to transvenous pacing in a pediatric population.

METHODS

Pediatric patients with congenital or acquired CAVB, who underwent a switch from epicardial-to transvenous pacing at our center from 2005 to 2021, were identified through the national ICD- and Pacemaker Registry. Data regarding clinical status, ECG, and echocardiography before and after the switch and at last follow-up were collected.

RESULTS

We included 15 children. The median age at the switch was 6.7 (4.4-11.7) years with a median weight of 21 (15-39) Kg. The median QRS duration with the transvenous systems was 136 (128-152) ms vs. a QRS duration during epicardial stimulation of 150 (144-170) ms with a median difference in QRS duration of 14 (6-20) ms. Children with a post-surgical AV block had a broader QRS duration, both with epicardial and endocardial stimulation. Before the switch, there was one patient with impaired left ventricular function (LVF) but with normal left ventricular end-diastolic diameters. After the switch, one patient developed symptomatic LV dysfunction with the recovery of LVF at the last follow-up after being implanted with a cardiac resynchronization therapy device.

CONCLUSIONS

Our report of pediatric patients after switching from epicardial to transvenous pacing shows how transvenous pacing is not inferior to epicardial pacing in terms of QRS duration and no significant deterioration of cardiac function was detectable.

Prevalence of neonatal lupus in a small group of antibody-carrying mothers and frequency of complete atrioventricular block

BACKGROUND

Neonatal lupus (NL) is extremely rare and is caused by the transplacental passage of maternal IgG autoantibodies against Ro, La, and/or RNP proteins into the fetal circulation, which can cause congenital complete atrioventricular block (CCAB), permanent skin lesions, and liver involvement.

OBJECTIVE

To know the prevalence of NL in patients with CCAB and the clinical course in long-term follow-up.

METHODS

From January 1992 to December 2017, patients with CCAB were included. The presence of anti-SSA/Ro and anti-SSB/La antinuclear antibodies in maternal serum confirmed NL.

RESULTS

Eight patients were included with a follow-up of 10 ± 6 years; NL was concluded in 62.5%; two were male. One of them was diagnosed in utero, two at birth, and a pacemaker was implanted in them, one at 12 years of age and another at 15. The other two cases were diagnosed at 18 and 26 years of age, and permanent pacemakers were implanted 8 and 5 years later, respectively. In one case, a definitive pacemaker was not implanted in a newborn with only 1 year of follow-up. At delivery, 60% of the mothers were free of rheumatic disease, and altogether, they all had 19 children; none of them presented NL manifestations.

CONCLUSIONS

CCAB is rare and frequently associated with a maternal autoimmune disease, practically all of them will require a definitive pacemaker at some point in their lives.

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.

Identifying Congenital Heart Block in Primary Care

Congenital heart block is a rare disease characterized by electrical conduction abnormalities of the heart in patients with both structural and without structural abnormalities. The most common cause of congenital heart block is autoimmune related, but other potential causes exist. Treatment for congenital heart block is determined by the severity of the disease and presenting symptoms. Primary care providers are in the optimal position to support patients and families. Although common causes and treatments of congenital heart block are known, much research is still to be done on the cause, optimal treatments, and potential long-term side effects.

Harnessing cell reprogramming for cardiac biological pacing

Electrical impulses from cardiac pacemaker cardiomyocytes initiate cardiac contraction and blood pumping and maintain life. Abnormal electrical impulses bring patients with low heart rates to cardiac arrest. The current therapy is to implant electronic devices to generate backup electricity. However, complications inherent to electronic devices remain unbearable suffering. Therefore, cardiac biological pacing has been developed as a hardware-free alternative. The approaches to generating biological pacing have evolved recently using cell reprogramming technology to generate pacemaker cardiomyocytes in-vivo or in-vitro. Different from conventional methods by electrical re-engineering, reprogramming-based biological pacing recapitulates various phenotypes of de novo pacemaker cardiomyocytes and is more physiological, efficient, and easy for clinical implementation. This article reviews the present state of the art in reprogramming-based biological pacing. We begin with the rationale for this new approach and review its advances in creating a biological pacemaker to treat bradyarrhythmia.

Influence of Diameter and Cyclic Mechanical Stimulation on the Beating Frequency of Myocardial Cell-Laden Fibers

Atrioventricular block (AVB) is a severe disease for pediatric patients. The repetitive operations needed in the case of the pacemaker implantation to maintain the electrical signal at the atrioventricular node (AVN) affect the patient's life quality. In this study, we present a method of biofabrication of multi-cell-laden cylindrical fibrin-based fibers that can restore the electrical signal at the AVN. We used human umbilical vein smooth muscle cells (HUVSMCs), human umbilical vein endothelial cells (HUVECs) and induced pluripotent stem cell cardiomyocytes (iPSC-CMs) cultivated either statically or dynamically to mimic the native AVN. We investigated the influence of cell composition, construct diameter and cyclic stretch on the function of the fibrin hydrogels in vitro. Immunohistochemistry analyses showed the maturity of the iPSC-CMs in the constructs through the expression of sarcomeric alpha actinin (SAA) and electrical coupling through Connexin 43 (Cx43) signal. Simultaneously, the beating frequency of the fibrin hydrogels was higher and easy to maintain whereas the concentration of iPSC-CMs was higher compared with the other types of cylindrical constructs. In total, our study highlights that the combination of fibrin with the cell mixture and geometry is offering a feasible biofabrication method for tissue engineering approaches for the treatment of AVB.

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.

Calreticulin: Endoplasmic reticulum Ca2+ gatekeeper

Endoplasmic reticulum (ER) luminal Ca2+ is vital for the function of the ER and regulates many cellular processes. Calreticulin is a highly conserved, ER-resident Ca2+ binding protein and lectin-like chaperone. Over four decades of studying calreticulin demonstrate that this protein plays a crucial role in maintaining Ca2+ supply under different physiological conditions, in managing access to Ca2+ and how Ca2+ is used depending on the environmental events and in making sure that Ca2+ is not misused. Calreticulin plays a role of ER luminal Ca2+ sensor to manage Ca2+ -dependent ER luminal events including maintaining interaction with its partners, Ca2+ handling molecules, substrates and stress sensors. The protein is strategically positioned in the lumen of the ER from where the protein manages access to and distribution of Ca2+ for many cellular Ca2+ -signalling events. The importance of calreticulin Ca2+ pool extends beyond the ER and includes influence of cellular processes involved in many aspects of cellular pathophysiology. Abnormal handling of the ER Ca2+ contributes to many pathologies from heart failure to neurodegeneration and metabolic diseases.

A rare case with fetal autoimmune heart block and KNCH2 variant-induced long QT syndrome: a controversial opinion on prenatal management strategy

BACKGROUND

Among all fetal heart block patients, > 50% cases are associated with maternal autoimmune diseases, and such patients should receive treatment. However, nearly half of fetal heart block cases involve a mother with negative results following autoimmune antibody screening. A few studies have reported long QT syndrome (LQTS) can also present as a severe fetal bradycardia, which does not respond to fetal treatment. Herein, we reported a rare case of an infant who presented with high-degree autoimmune-mediated fetal atrioventricular block (AVB) with LQTS induced by a novel KCNH2 variant. This case led us to review our prenatal therapeutic strategy.

CASE PRESENTATION

A 1-year-old boy presented to our heart center having experienced syncope 5 times in the past year. He had previously presented with fetal bradycardia during the fetal stage from 27 + 3 gestational weeks. The fetal echocardiography demonstrated AVB (2:1 transmission). As the maternal autoimmune antibody results were positive, his mother had received dexamethasone treatment during pregnancy; subsequently, the fetal AVB had changed from 2:1 to 4:3 transmission with elevated ventricular beating rates. However, this patient was identified to have complete AVB after birth. The initial electrocardiogram and Holter measurements at hospital administration showed complete AVB, pleomorphic ventricular tachycardia, a prolonged QT interval (QT = 602 ms, corrected QT = 538 ms), and wide and deep inverted T-waves. Meanwhile, torsades de pointes could be observed in several transit ventricular tachycardias based on Holter monitoring review. Genetic testing revealed KCNH2 c.2483G > A variant-induced LQTS. An implantable cardioverter defibrillator device and permanent pacemaker were both considered as therapeutic alternations; his parents ultimately accepted the implantation of a permanent pacemaker.

CONCLUSIONS

For fetuses with autoimmune-mediated AVB, intrauterine treatment should still be pursued immediately. However, once the treatment outcomes are deemed unacceptable or unexpected, other genetic variant-related channelopathies should be highly suspected. If the fetus lacks a positive family history, fetal genetic testing should be recommended to improve the prognosis of such patients by introducing integrative therapeutic strategies between the prenatal and postnatal phases.

Atrioventricular Block in Celiac Disease: An Unusual Clinical Presentation in a Child. A Case-Based Review

Congenital or acquired atrioventricular block (AVB) is a rare disorder in the pediatric population, while celiac disease (CeD) is a common multisystemic autoimmune disorder that is characterized by intestinal manifestations as they are the typical clinical presentation. Sometimes CeD presents more complex multisystemic involvement which includes the heart. Cardiac involvement, such as dilated cardiomyopathy, myocarditis or conduction disease, have been mainly described in untreated adult patients with or without gastro-intestinal symptoms; rare cases of AVB and CeD have been also reported, particularly in association with extra-cardiac manifestations. We describe a case of a progressive acquired AVB block in a 4-year-old child, in which CeD was later diagnosed. A rapid and significantly improvement of the AVB grade has been obtained after the child started a strict gluten-free diet, and so we suggest including diagnostic exams for CeD in all of the children with acquired AVB.

Minimally invasive permanent pacemaker implantation immediately after birth: from delivery room to heart surgery

INTRODUCTION

Congenital atrioventricular block is diagnosed in uterine life, at birth, or early in life. Atrioventricular blocks can be life threatening immediately at birth so urgent pacemaker implantation techniques are requested. Reasons can be cardiac or non-cardiac, but regardless of the reason, operations are challenging. We aimed to present technical procedure and operative results of pacemaker implantation in neonates.

MATERIALS AND METHODS

Between June 2014 and February 2021, 10 neonates who had congenital atrioventricular block underwent surgical operation to implant permanent epicardial pacemaker by using minimally invasive technique. Six of the patients were female and four of them were male. Mean age was 4.3 days (0-11), while three of them were operated on the day of birth. Mean weight was 2533 g (1200-3300).

RESULTS

Operations were achieved through subxiphoidal minimally skin incision. Epicardial 25 mm length dual leads were implanted on right ventricular surface and generators were fixed on the right (seven patients) or left (three patients) diaphragmatic surface by incising pleura. There were no complication, morbidity, and mortality related to surgery.

CONCLUSION

Few studies have characterised the surgical outcomes following epicardial permanent pacemaker implantation in neonates. The surgical approach is attractive and compelling among professionals so we aimed to present the techniques and results in patients who required permanent pacemaker implantation in the first month of life.

Diagnostic Yield of Genetic Testing in Young Patients With Atrioventricular Block of Unknown Cause

Background

The cause of atrioventricular block (AVB) remains unknown in approximately half of young patients with the diagnosis. Although variants in several genes associated with cardiac conduction diseases have been identified, the contribution of genetic variants in younger patients with AVB is unknown.

Methods and Results

Using the Danish Pacemaker and Implantable Cardioverter Defibrillator (ICD) Registry, we identified all patients younger than 50 years receiving a pacemaker because of AVB in Denmark in the period from January 1, 1996 to December 31, 2015. From medical records, we identified patients with unknown cause of AVB at time of pacemaker implantation. These patients were invited to a genetic screening using a panel of 102 genes associated with inherited cardiac diseases. We identified 471 living patients with AVB of unknown cause, of whom 226 (48%) accepted participation. Median age at the time of pacemaker implantation was 39 years (interquartile range, 32–45 years), and 123 (54%) were men. We found pathogenic or likely pathogenic variants in genes associated with or possibly associated with AVB in 12 patients (5%). Most variants were found in the LMNA gene (n=5). LMNA variant carriers all had a family history of either AVB and/or sudden cardiac death.

Conclusions

In young patients with AVB of unknown cause, we found a possible genetic cause in 1 out of 20 participating patients. Variants in the LMNA gene were most common and associated with a family history of AVB and/or sudden cardiac death, suggesting that genetic testing should be a part of the diagnostic workup in these patients to stratify risk and screen family members.

[Morphofunctional characteristics of the heart in sudden death of children under 1 year of age in the forensic medical aspect]

The aim of this study is to describe the morphological and functional characteristics of the cardiac in sudden infants death syndrome (SIDS) in children under one year of age. Twenty eight cases of SIDS were studied histologically and immunohistochemically. Histological examination of the sectional material was carried out using standard and additional stains. The study of cardiac muscle tissue with routine staining with haematoxylin-eosin revealed interstitial oedema, uneven plethora of blood vessels: dystonia and weak plethora of part of the coronary arteries, excess of red blood cells in the veins as well as microcirculatory plethora with stasis of the erythrocytes. An immunohistochemical study revealed a mild over expression of p53 in cellular elements, small-focal expression of CD68 in cardiomyocytes apoptosis intramural areas, activation of mast cells (CD117), expression of ki-67 in macrophages, proliferation of fibroblasts. Additional forensic criteria for the diagnosis of SIDS were determined in the form of atrial endocardial fibrosis and interventricular septum; the expression of CD68, CD117 in fibroblasts, mast cells and lymphocytes; apoptosis of cardiomyocytes (expression of p53), proliferation of fibroblasts and remodeling of the heart (expression of ki-67).

Sudden Cardiac Arrest in the Paediatric Population

Sudden cardiac arrest in the young is a rare event with a range of potential causes including cardiomyopathies, ion channelopathies, and autonomic nervous system dysfunction. Investigations into the cause involve a multidisciplinary team, including cardiologists, geneticists, and psychologists. In addition to a detailed medical history, family history and circumstances surrounding the event are important in determining the cause. Clinical investigations including an electrocardiogram are fundamental in diagnosis and should be interpreted cautiously because some children may have atypical presentations and an evolving phenotype. The potential for misdiagnosis exists that could lead to incorrect long-term management strategies. If an inherited condition is suspected, genetic testing of the patient and cascade screening of family members is recommended with genetic counselling and psychological support. Medical management is left to the treating physician acknowledging that a clear diagnosis cannot be made in approximately half of cases. Secondary prevention implantable defibrillators are widely deployed but can be associated with complications in young patients. A plan for safe return to activity is recommended along with a proper transition of care into adulthood. Broad screening of the general population for arrhythmia syndromes is not recommended; preventative measures include screening paediatric patients for risk factors by their primary care physician. Several milestone events or activities that take place in youth could be used as opportunities to promote safety. Further work into risk stratification of this paediatric population through patient registries and greater awareness of cardiopulmonary resuscitation and automated external defibrillator use in saving lives is warranted.

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.

Meningitis and high-grade, second-degree atrioventricular block in an adolescent: causal effect or coincidence?

We describe an adolescent with Streptococcus pneumoniae meningitis and symptomatic high-grade, second-degree atrioventricular block requiring permanent pacemaker placement. It is difficult to ascertain if these two diagnoses were independent or had a causal relationship though ongoing symptoms were not present prior to the infection. Because of this uncertainty, awareness that rhythm disturbances can be cardiac in origin but also secondary to other aetiologies, such as infection, is warranted.

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.

Intermittent atrio-ventricular block and ectopy in an infant following complex heart surgery: Occam's razor versus Hickam's dictum

Concealed functional extra-systole manifesting as pseudo Mobitz Type II Second Degree A-V Block.

Cellular regeneration as a potential strategy to treat cardiac conduction disorders

Loss of atrioventricular conduction system (AVCS) cells due to either inherited or acquired deficits leads to conduction diseases, which can deteriorate into fatal cardiac arrhythmias and sudden death. In this issue of the JCI, Wang et al. constructed a mouse model of atrioventricular block (AVB) by inducing AVCS cell-specific injury using the Cx30.2 enhancer to drive expression of diphtheria toxin fragment A. AVCS cell ablation in adult mice led to irreversible AVB. jkjkIn contrast, AVCS cell injury in neonatal mice was followed by spontaneous recovery in a subset of mice, revealing a limited postnatal time window during which the regeneration of AVCS cells can occur as a result of cellular plasticity. This exciting study paves the way for future research into biological or cellular treatment approaches for cardiac conduction diseases by exploiting the regenerative potential of AVCS cells.

Etiology and device therapy in complete atrioventricular block in pediatric and young adult population: Contemporary review and new perspectives

Complete atrioventricular block (CAVB) is a total dissociation between the atrial and ventricular activity, in the absence of atrioventricular conduction. Several diseases may result in CAVB in the pediatric and young-adult population. Permanent right ventricular (RV) pacing is required in permanent CAVB, when the cause is neither transient nor reversible. Continuous RV apical pacing has been associated with unfavorable outcomes in several studies due to the associated ventricular dyssynchrony. This study aims to summarize the current literature regarding CAVB in the pediatric and young adult population and to explore future treatment perspectives.

Transient Congenital Complete Heart Block: A Case Report

Congenital complete heart block is defined as a complete atrioventricular block occurring prenatally, at birth, or within the first month of life. Congenital complete heart block has a high mortality rate, and in infants with normal heart morphology, it is often associated with maternal connective tissue disease. In these latter cases, neonatal congenital complete heart block is usually irreversible. We present a rare case of a female neonate who had bradycardia noted at a gestational age of 37 weeks. Her mother had no autoimmune disease history. She had no structural heart disease, and the serology surveys for autoantibodies including SSA/Ro and SSB/La were all negative. Without intervention or medication, her congenital complete heart block completely recovered to a normal sinus rhythm within 5 days. The cause of the transient congenital complete heart block was unknown in this case.

Intrapleural pocket for pediatric epicardial pacemaker via right axillary incision

Congenital and acquired complete heart block (CHB) are serious conduction abnormalities that may necessitate permanent pacemaker placement. Small patient size and anatomy preclude transvenous pacemaker insertion and risk subcutaneous generator pocket complications. We describe placement of a pediatric bipolar epicardial pacemaker via right axillary incision with an intrapleural polytetrafluoroethylene (PTFE) membrane pocket to facilitate future generator exchange.

Emergency department management of patients with adult congenital heart disease: a consensus paper from the ESC Working Group on Adult Congenital Heart Disease, the European Society for Emergency Medicine (EUSEM), the European Association for Cardio-Thoracic Surgery (EACTS), and the Association for Acute Cardiovascular Care (ACVC)

Adult congenital heart disease (ACHD) patients represent a growing population with increasing use of acute emergency department (ED) care. Providing comprehensive ED care necessitates an understanding of the most common clinical scenarios to improve morbidity and mortality in this population. The aim of this position document is to provide a consensus regarding the management of the most common clinical scenarios of ACHD patients presenting to the ED.

Incidental electrocardiogram abnormalities in children undergoing polysomnography

STUDY OBJECTIVES

Monitoring electrocardiogram (ECG) is an integral component of pediatric polysomnography (PSG). There is limited data regarding arrhythmia and conduction disturbances in the pediatric population undergoing a PSG. In this work we present abnormal ECG findings during PSG in our sleep center.

METHODS

A retrospective chart review from children who underwent PSG read by a single Sleep Medicine physician in the last year was carried out. Findings in children without cardiac disease and with first or second degree atrioventricular block (AVB) were compared to those from children with premature ventricular contractions (PVC).

RESULTS

A total of 1,235 PSGs were included. Twenty-four children (9 girls and 15 boys) aged 2-17 years (median 9 years) were identified with arrhythmias or conduction disturbances (1.9%). Nineteen out of 24 of these children (79.2%) had obstructive apnea-hypopnea index (oAHI) > 1 event/h; this frequency was not significantly different from that found in the whole group of 1,235 children. No statistically significant difference was found between children with AVB or PVC. Seven out of nine children with AVB and seven out of 10 with PVC had oAHI > 1 event/h, while eight children with AVB out of nine and four out of 10 with PVC were males (Fisher exact test p=0.04). None of the children were found to have a structural or conduction abnormality when referred to cardiology.

CONCLUSIONS

Our study supports that ECG abnormalities are rare in PSGs of children and not associated with cardiac disease or sleep disorders but appear more commonly in males.

A novel LMNA indel mutation identified in a family with atrioventricular block and atrial fibrillation

It is well known that many genetic factors are involved in the occurrence and progression of atrioventricular block (AV block) and atrial fibrillation (AF). However, the genetic variants discovered so far have only explained parts of these processes. More genes and variants remain to be identified. In the present study, a three-generation family with an autosomal dominant form of AV block and AF was enrolled. Whole exome sequencing was conducted in three affected and one unaffected family member. A total of 64 nonsynonymous variants was shared by three affected individuals and not present in the unaffected individual. By selection of variants absent in the known databases and were predicted to be deleterious, 4 novel variants were identified. Only one novel frameshift insertion in the LMNA gene (c.825_826insCAGG) was identified in another affected family member and not detected in other non-affected family members and the 100 controls. Our finding expanded the spectrum of variants associated with AV block and AF, and was valuable in the genetic diagnosis of AV block and AF.

Innovation in Permanent Pacemaker's Implantation Technique: Trans-Axillary Approach

Introduction: Permanent pacemakers’ (PPM) implantation is an integral part of electrophysiology and general cardiology. The implantation technique has evolved a lot since the first implantation. Several innovations have been undertaken to improve the effectiveness, life of the transplant, and patient outcomes. In this study, we introduced a new implantation technique to improve the procedure and possibly reduce the rate of complication.

Methods: This study was conducted from January 2016 to February 2017 in Hayatabad Medical Complex, Peshawar. Patients destined for implantation of PPM based on a clinical treatment plan, after proper explanation of the procedure, were brought to the catheterization laboratory. Venogram of the upper limb performed. Patients were scrubbed and draped. The axillary vein was approached via the Seldinger technique. About 2 to 3 cm superolateral to the puncture site, a skin incision was made and subcutaneous pocket constructed, and a guidewire external end was pulled in from inside the pocket keeping the venous end at the place. Subsequently, in a routine way, lead was placed, secured and the wound was closed in layers.

Results: A total of 690 PPM were implanted under the study. About 290 devices were implanted in the conventional way and 380 devices via the trans-axillary approach. The mean implantation time was less than 30 minutes via the trans-axillary approach. Immediate and delayed complications of the procedure were minimal.

Conclusion: Trans-axillary approach holds some significant advantages over the conventional technique. The subcutaneous pocket and venous puncture successfully reduce the burden of foreign material, minimize the tension on the wound, shorten implantation time and reduce the chances of erosion of the device. 

[Fetal ECG and arrhythmias]

The normal fetal heart rate ranges between 110 und 180 beats per minute (bpm). Intrauterine arrhythmias are not an uncommon finding. Fetal echocardiography (ECG) allows for correct diagnosis of the arrhythmia, which is prerequisite for decision making and treatment. Most fetal rhythm disturbances are the result of premature atrial contractions and are of little clinical significance. Intrauterine bradycardias (heart rate < 110 bpm) result from sinus node dysfunction, complete AV block and nonconducted atrial bigeminy. Isolated complete heart block related to maternal anti-SSA/Ro or SSB/La auto-antibodies is irreversible in almost all fetuses. Anti-inflammatory therapy and chronotropic medication may improve outcome. Newborn babies often require pacemaker implantation to augment cardiac output. Intrauterine tachycardias (heart rate > 180 bpm) are most commonly related to supraventricular tachycardia and atrial flutter. Specific antiarrhythmic medication is available to stop the arrhythmia and to prevent hemodynamic deterioration.

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.

Arrhythmias in Neonates and Infants at a Tertiary Care Center

Background Limited data about arrhythmias in neonates and infants are coming out from the Middle East. Objectives To evaluate different types of arrhythmias in neonates and infants at the American University of Beirut Medical Center (AUBMC), a tertiary care center in Lebanon, with the focus on the nature of arrhythmia, treatment modalities and relation to surgery. Methods Data were collected retrospectively from the hospital records. We included all neonates and infants presenting to AUBMC between 2013 and 2017. Collected data included: the type of arrhythmia, the treatment modality used and its success, the need for additional modes of treatment, the relationship to congenital heart diseases, and the cardiac surgeries performed. Results Of 16,346 subjects admitted to AUBMC between 2013 and 2017, 90 subjects developed arrhythmias that required medical intervention. The most frequent types of arrhythmias were supraventricular tachycardia (62.22%), junctional ectopic tachycardia (13.33%), complete heart block (7.78%), atrial flutter (5.56%), multifocal atrial tachycardia (3.33%), Wolf Parkinson White Syndrome (3.33%), non-sustained ventricular tachycardia (2.22%), sinus pause (1.11%), and premature ventricular contractions (1.11%). Bivariate analysis showed a significant difference between arrhythmias not related to cardiac surgery and arrhythmias related to cardiac surgery in terms of the type of arrhythmia developed, the presence of congenital heart defect, prematurity, and electrolyte disturbances (P-value <0.005). However, multivariate logistic regression showed no significant difference between the two groups after adjustment for the significant variables (P-value > 0.05). Conclusion There is a significant difference between arrhythmias not related to cardiac surgery and arrhythmias related to cardiac surgery in neonates and infants at AUBMC. However, the difference disappears after adjusting for different variables.

Evaluation and Management of Asymptomatic Bradyarrhythmias

Asymptomatic bradyarrhythmias involving sinus node dysfunction and atrioventicular blocks are frequently noted in clinical practice. Its prevalence is expected to rise as devices that are developed for monitoring cardiac rhythm for longer duration become more widely available. Episodes of bradyarrhythmia that are asymptomatic are considered to have a benign course compared with those that cause symptoms and do not necessitate further treatment. However, in certain cases, they can be a harbinger of future symptoms or cardiac manifestations of systemic diseases. The evaluation and risk stratification of individuals presenting with asymptomatic bradyarrhythmias is important not only for preventing implantation of unnecessary permanent pacing devices but also for reducing significant morbidity by implementing proper treatment as required. In this article, we will review the current evidence on the pathophysiology, diagnosis, evaluation and management of patients with asymptomatic bradyarrhythmias.

Video-assisted thoracoscopic pacemaker lead placement in children with atrioventricular block

Background:

The pacemaker lead placement is presented as one of the most appropriate procedures in children with a complete atrioventricular block (AVB). Despite the fact that video-assisted thoracic surgery (VATS) for epicardial lead placement has demonstrated positive results as to the feasibility, safety, and efficacy in adults, its role in pacemaker implantation in children remains unclear.

Aim:

This study sought to assess the intermediate-term outcomes of video-assisted thoracoscopic pacemaker lead placement in children with complete AVB

Materials and Methods:

From May 2017 to November 2019, five children with complete AVB underwent minimally invasive left ventricular (LV) lead placements via thoracoscopic video assistance approach. The procedure was performed under complex intratracheal anesthesia with single-lung ventilation, all pacing parameters were evaluated in perioperative and follow-up periods.

Results:

The median age of children at implantation was 3 years (range: 2 to 4 years), the median weight was 13 kg (range: 12–15 kg). All procedures were completed successfully, pacing thresholds for the active lead measured 0.3-1.1V, with R-wave amplitude of 8-18 mV and impedance of 560-1478 Ohm.

Conclusion:

Thoracoscopic pacemaker lead placement may provide a potential alternative to the transthoracic approach of epicardial lead placement in children with AVB.

Juvenile dermatomyositis presenting as complete heart block in a 10-year-old girl

Juvenile dermatomyositis (JDM) is an auto-immune inflammatory condition associated with cardiac disorders including conduction abnormalities and myocardial dysfunction. The time of presentation of cardiac abnormalities can range from disease onset to after long-term follow-up, emphasising the importance of screening for cardiac involvement in JDM. A previously healthy 10-year-old girl presented with syncope, fatigue and weakness associated with a heliotrope rash. JDM was diagnosed based on the clinical, laboratory and imaging findings. An ECG demonstrated complete heart block (CHB). All symptoms resolved following treatment with parenteral corticosteroids. In JDM, it is important to investigate for cardiac manifestations and in CHB to consider administering corticosteroids.

Case Report: Pediatric Patient with COVID-19 and Multisystem Inflammatory Syndrome in Children

INTRODUCTION

Coronavirus disease 2019 (COVID-19) rarely manifests with severe complications in pediatric patients. An association between COVID-19 and a Kawasaki-like inflammatory syndrome has recently presented in pediatric patients.

CASE REPORT

We report a unique case of multisystem inflammatory syndrome in children presenting with characteristic findings in a child who later developed cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation.

CONCLUSION

Recognition of these early signs and symptoms facilitates screening and risk stratification of pediatric COVID-19 cases associated with increased morbidity.

Reversible hypertension associated with complete heart block in a 6-year-old boy

We herein report a case of a 6-year-old boy with hypertension and complete heart block with a unique outcome. The patient was treated with an epicardial pacemaker followed by complete and sustained resolution of his hypertension with no further need for the previously prescribed antihypertensive medication.

Surgical pericardial adhesions do not preclude minimally invasive epicardial pacemaker lead placement in an infant porcine model

BACKGROUND

Pericardial adhesions in infants and small children following cardiac surgery can impede access to the epicardium. We previously described minimally invasive epicardial lead placement under direct visualization in an infant porcine model using a single subxiphoid incision. The objective of this study was to assess the acute feasibility of this approach in the presence of postoperative pericardial adhesions.

METHODS

Adhesion group piglets underwent left thoracotomy with pericardiotomy followed by a recovery period to develop pericardial adhesions. Control group piglets did not undergo surgery. Both groups underwent minimally invasive epicardial lead placement using a 2-channel access port (PeriPath) inserted through a 1 cm subxiphoid incision. Under direct thoracoscopic visualization, pericardial access was obtained with a 7-French sheath, and a pacing lead was affixed against the ventricular epicardium. Sensed R-wave amplitudes, lead impedances and capture thresholds were measured.

RESULTS

Eight piglets underwent successful pericardiectomy and developed adhesions after a median recovery time of 45 days. Epicardial lead placement was successful in adhesion (9.5 ± 2.7 kg, n = 8) and control (5.6 ± 1.5 kg, n = 7) piglets. There were no acute complications. There were no significant differences in capture thresholds or sensing between groups. Procedure times in the adhesion group were longer than in controls, and while lead impedances were significantly higher in the adhesion group, all were within normal range.

CONCLUSIONS

Pericardial adhesions do not preclude minimally invasive placement of epicardial leads in an infant porcine model. This minimally invasive approach could potentially be applied to pediatric patients with prior cardiac surgery.

Lung complications of Sjogren syndrome

Primary Sjogren syndrome (pSS) is a systemic autoimmune disease characterised by lymphocytic infiltration of exocrine glands and by a number of systemic manifestations, including those regarding the lung. Pulmonary involvement in pSS includes interstitial lung disease (ILD) and airway disease, together with lymphoproliferative disorders.

Patients with pSS-ILD report impaired health-related quality of life and a higher risk of death, suggesting the importance of early diagnosis and treatment of this type of pulmonary involvement. In contrast, airway disease usually has little effect on respiratory function and is rarely the cause of death in these patients.

More rare disorders can be also identified, such as pleural effusion, cysts or bullae.

Up to date, available data do not allow us to establish an evidence-based treatment strategy in pSS-ILD. No data are available regarding which patients should be treated, the timing to start therapy and better therapeutic options. The lack of knowledge about the natural history and prognosis of pSS-ILD is the main limitation to the development of clinical trials or shared recommendations on this topic. However, a recent trial showed the efficacy of the antifibrotic drug nintedanib in slowing progression of various ILDs, including those in pSS patients.

Primary Sjogren syndrome is a systemic autoimmune disease with a possible lung involvement, that it appears as polymorphic, including interstitial lung disease, airway disease and lymphoproliferative disorders with different degree of severityhttps://bit.ly/3akjk4b