Congenital and childhood atrioventricular blocks: pathophysiology and contemporary management

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

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.

Electrocardiogram interpretation among pediatricians: Assessing knowledge, attitudes, and practice

Objectives:

This study assesses the competency of pediatricians in interpreting electrocardiograms (ECGs).

Methods:

A cross-sectional study involving 125 pediatricians comprised of 71 general pediatricians, 15 pediatric cardiologists, and 39 other subspecialists recruited from all public hospitals and two specialty centers. Participants completed a questionnaire that included 10 ECGs and questions regarding backgrounds, attitudes, and practices. The ECGs were graded to obtain a knowledge score out of 30 points. Mann–Whitney U test and Kruskal-Wallis test with post hoc analysis and Bonferroni adjustment were used to compare groups.

Results:

The mean knowledge score ranged from 47.7% to 69.7% among various pediatric specialties (P = 0.006). Age, increasing years of experience, confidence level, number of cardiology referrals, and perceived importance of having good ECG interpretation skills were significantly related to the knowledge score (P ≤ 0.05). Accuracy was highest in identifying normal ECGs (76.8%), supraventricular tachycardia (64.8%), along with long QT interval (58.4%), and was lowest for right bundle branch block (RBBB) (10.4%), 2:1 atrioventricular conduction (10.4%), and atrial tachycardia (AT) (4.8%). Accuracy among pediatric cardiologists was highest for long QT interval (100%), normal ECG (80%), as well as Wolff-Parkinson-White syndrome (80%), and lowest for RBBB (13.3%) and AT (0%). Most pediatricians believe that ECGs are “useful” (78.4%) and that having good interpretation skill is “important” (80.6%).

Conclusions:

Pediatricians recognize the importance of ECGs. However, their skill and level of accuracy at interpretation is suboptimal, including cardiologists, and may affect patient care. Thus, efforts should be made to improve ECG understanding to provide better service to patients.

Early Disseminated Lyme Carditis Inducing High-Degree Atrioventricular Block

Lyme disease is the most common tick-borne illness in the United States due to Borrelia burgdorferi infection. This case demonstrates a 20-year-old male patient presenting with complaints of annular skin rash, malaise, fever, and lightheadedness after significant outdoor exposure. Physical exam revealed multiple large targetoid lesions on the back and extremities. The rash had raised borders and centralized clearing consistent with erythema migrans chronicum. Electrocardiogram (ECG) revealed a high-degree atrioventricular (AV) block. The patient was started on intravenous ceftriaxone due to clinical suspicion for Lyme carditis. ELISA and Western blot tests were reactive for Lyme IgM and IgG, confirming the diagnosis. The AV block resolved by hospital day four and the patient was discharged with outpatient follow-up. Early identification of disease allowed for effective treatment with no adverse outcomes or sequelae.

Antisynthetase syndrome in pregnancy: A case and review of the literature

Antisynthetase syndrome is a rare autoimmune, multisystem, inflammatory condition, characterised by autoantibodies against aminoacyl tRNA synthetases. The predominant features are myositis and interstitial lung disease but other symptoms such as Raynaud's phenomenon may also be present. Described here is a 36-year-old woman with antisynthetase syndrome who planned and underwent a successful pregnancy, during which a multidisciplinary team approach secured a good outcome for both mother and baby.

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

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

Prenatal diagnosis and management of congenital complete heart block

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

Modern Technology for Prevention of Sudden Cardiac Death – a Clinical Update on Device Therapy in Children with Congenital Heart Diseases

Sudden cardiac death in children is one of the most devastating conditions that can be encountered in acute cardiac care. Intracardiac device therapy, providing prompt and effective treatment in malignant ventricular arrhythmia or in severe conduction abnormalities, is a promising tool to reduce the incidence of this fatal condition. However, the implementation of device-based therapy in the pediatric population is currently limited by the lack of clinical studies on large number of subjects. As a result, indications for device therapy in pediatric patients are still unclear in many circumstances. There are also several particularities related to device implantation in pediatric age, such as the somatic growth leading to a mismatch between chamber size and lead length, or the difficulties of implantation technique in children with small body weight. This study aims to present an update on the current advantages and limitations of device-based therapy for treating severe malignant arrhythmia or conduction disorders in children at risk for sudden cardiac death.

A Case of Congenital Complete Atrioventricular Block Treated with Transdermal Tulobuterol

Congenital complete atrioventricular block (CCAVB) is a condition in which the atria and ventricles beat independently of each other. CCAVB cases require permanent pacemaker implantation until adulthood. Nevertheless, consensus regarding postnatal medical therapy for bradycardia has not been reached. Here we report the case of a newborn with CCAVB, whose intractable bradycardia was successfully treated with transdermal tulobuterol. Tulobuterol is a selective β2-adrenoceptor agonist, widely used safely as bronchodilator in children. It also has positive inotropic and chronotropic effect via β1-adrenoceptors. We believe the tulobuterol patch can be used as an optional therapy for CCAVB where pacemaker implantation is not available.

Chronic Low Dose Prostaglandin and Neonatal Heart Block

Long-term prostaglandin use is commonly associated with side effects such as cortical proliferation of the bones, hypertrophic pyloric stenosis, and soft tissue swelling of the extremities. We report a neonate with critical coarctation of the aorta, who developed second and third degree atrioventricular blocks associated with prolonged prostaglandin E1 (PGE1) infusion. Interestingly, these conduction blocks only occurred at low PGE1 dose. The rhythm disturbances resolved promptly with the discontinuation of PGE1 following surgical repair.

Undifferentiated connective tissue diseases and adverse pregnancy outcomes. An undervalued association?

Undifferentiated connective tissue diseases (UCTDs) are a heterogeneous group of disorders characterized by symptoms and signs suggestive of systemic autoimmune rheumatic disease (ARD), but which do not fulfill all the established criteria for definite diagnosis of a condition. Although a third of UCTDs can progress to a definite ARD within months or years, most UCTDs can remain stable for years with minimal disease activity. The annual incidence of UCTD in the general population ranges from 14 to 140 per 100 000 people. UCTDs are associated with the persistence of several circulating autoantibodies including antinuclear, antiphospholipid or antithyroid antibodies. Immunological evaluation of subjects with UCTDs suggests a proinflammatory state and dysregulation of the Th1/Th2 balance. Autoantibodies have well-known deleterious effects on placentation and have been associated with an increased risk of prematurity, fetal growth restriction (FGR), preeclampsia, and congenital atrioventricular heart block. Although epidemiological and biological data suggest a potential negative impact on reproductive outcomes, the relationship between UCTD and pregnancy outcomes has not been adequately studied. While awaiting definitive data from large studies, obstetricians should be aware that rheumatic disorders in their early, incomplete, or undifferentiated phases can adversely affect pregnancy outcomes, increasing the likelihood of pregnancy loss, FGR, preeclampsia, and prematurity.

Role of cardiac pacing in congenital complete heart block

INTRODUCTION

Congenital complete heart block affects 1/15,000 live-born infants, predominantly due to atrioventricular nodal injury from maternal antibodies of mothers with systemic lupus erythermatosus or Sjogren's syndrome. The majority of these children will need a pacemaker implanted prior to becoming young adults. This article will review the various patient and technical factors that influence the type of pacemaker implanted, and the current literature on optimal pacing practices. Areas covered: A literature search was performed using PubMed, Embase and Web of Science. Data regarding epicardial versus transvenous implants, pacing-induced ventricular dysfunction, alternative pacing strategies (including biventricular pacing, left ventricular pacing, and His bundle pacing), and complications with pacemakers in the pediatric population were reviewed. Expert commentary: There are numerous pacing strategies available to children with congenital complete heart block. The risks and benefits of the initial implant should be weighed against the long-term issues inherent with a life-time of pacing.

Familial Disease Is Not Always Genetic: A Family With Atrioventricular Block and Mitral Regurgitation

We present a family from a founder population referred for cardiogenetic evaluation for atrioventricular block in 3 siblings. Genetic testing, including whole-exome sequencing, did not identify a disease-causing mutation. After reconsidering the differential diagnosis, a nongenetic cause was identified. This case highlights the importance of a thorough clinical evaluation even when a genetic cause is seemingly obvious.