Dilated Cardiomyopathy in Children With Isolated Congenital Complete Atrioventricular Block

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.

miR Profile of Chronic Right Ventricular Pacing: a Pilot Study in Children with Congenital Complete Atrioventricular Block

Chronic ventricular pacing can lead to pacing-induced cardiomyopathy (PICM). Clinical data alone is insufficient to predict who will develop PICM. Our study aimed to evaluate the circulating miR profile associated with chronic right ventricular pacing in children with congenital complete AV block (CCAVB) and to identify candidate miRs for longitudinal monitoring. Clinical data and blood were collected from chronically paced children (N = 9) and compared with non-paced controls (N = 13). miR microarrays from the buffy coat revealed 488 differentially regulated miRs between groups. Pathway analysis predicted both adaptive and maladaptive miR signaling associated with chronic pacing despite preserved ventricular function. Greater profibrotic signaling (miRs-92a, 130, 27, 29) and sodium and calcium channel dysregulation (let-7) were seen in those paced > 10 years with the most dyregulation seen in a patient with sudden death vs. those paced < 10 years. These miRs may help to identify early adverse remodeling in this population.

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.

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.