Permanent cardiac pacing in children: choosing the optimal pacing site: a multicenter study

Dual- vs Single-Chamber Ventricular Pacing in Isolated Congenital Complete Atrioventricular Block in Infancy

BACKGROUND

The optimal pacemaker programming strategy for infants with isolated congenital complete atrioventricular block (CCAVB) remains unresolved. Dual-chamber pacing maintains atrioventricular synchrony and physiological heart rate variability but increases the burden of ventricular pacing on a myocardium that may be inherently prone to left ventricular (LV) dysfunction.

OBJECTIVES

This study sought to compare clinical outcomes of dual (DDD)- vs single (VVI)- chamber pacing in infants with CCAVB (DAVINCHI).

METHODS

A multicenter retrospective study (2006-2023) identified infants with CCAVB and pacemaker implant at <1 year, with single-site ventricular pacing and no significant congenital heart disease. Outcome measured were clinically significant LV dysfunction, mortality, and complications.

RESULTS

A total of 109 infants (64% autoimmune CCAVB) were identified, 60.6% had VVI pacing. Over a median follow-up of 5 years, 60 complications occurred in 47 subjects (43.1%). Smaller infants had more complications. Clinically significant LV dysfunction developed in 11 (10.1%) and was more frequent in DDD (21% vs 3%; P = 0.006). LV dysfunction resulted in mortality in 1 patient and 10 patients required a change in pacing mode. Independent risk factors for LV dysfunction were DDD pacing and neonatal implant. Right ventricular pacing lead placement had a higher HR (HR: 2.67) for LV dysfunction but was not statistically significant (P = 0.20).

CONCLUSIONS

DDD pacing increases LV dysfunction risk compared with VVI in infants with CCAVB. Single-chamber LV apical pacing should be considered in infants with isolated CCAVB who require pacing. There is a high risk of pacing-related complications, particularly with an increased risk of ventricular lead complications in low-weight neonates.

Changes in Non-invasive Myocardial Stroke Work Related to Variation in Pacing Sites and Heart Rates in Adolescents

Non-invasive assessment of myocardial work is a newly described technique to assess myocardial energetics. This has not been previously studied to assess the effects of right ventricular pacing at different sites or at different heart rates in children. We aimed to study the effects of right ventricular apical, septal, and His bundle pacing on myocardial work along with the effects of increasing heart rate. This was a prospective pilot study performed on six patients with structurally normal hearts and function following an electrophysiology study. Global work index and global work efficiency was highest during His pacing and lowest during right ventricular apical pacing. The global constructive work, index, and efficiency were progressively worse with increasing heart rates. In this prospective pilot study, we demonstrated that myocardial work indices differ depending on myocardial activation pattern and at different heart rates in pediatric patients. Myocardial performance as assessed by myocardial work efficiency is worse when pacing is performed at the right ventricular apex when compared to His and right ventricular septal pacing. Myocardial performance can be affected by higher heart rates, following a work-frequency relationship.

2021 European Society of Cardiology guidelines on cardiac pacing and cardiac resynchronisation therapy : Statement of endorsement by the NVVC

The European Society of Cardiology (ESC) has updated its guidelines on cardiac pacing and cardiac resynchronisation. As the majority are class II recommendations (61%) and based on expert opinion (59%), a critical appraisal for the Dutch situation was warranted. A working group has been established, consisting of specialists in cardiology, cardiothoracic surgery, geriatrics, allied professionals in cardiac pacing, and patient organisations with support from the Knowledge Institute of the Dutch Association of Medical Specialists. They assessed the evidence leading to the recommendations and the suitability for daily Dutch practice. Several recommendations have been amended or omitted altogether if a conflicting Dutch guideline has recently been published, such as a guideline on performing magnetic resonance imaging in patients with cardiac implantable electronic devices. The recent Dutch guideline on implantable cardioverter defibrillator implantation in patients with non-ischaemic cardiomyopathy has recommended implanting cardiac resynchronisation therapy devices without a defibrillator function. Shared decision making has received a more prominent role in the ESC guidelines and is discussed in more detail in this document. The recommendations given in this document are intended for health care professionals involved in the care of patients with an indication for cardiac pacing and are approved by the participating professional societies and the patient organisation Harteraad.

Impact of permanent pacemaker for iatrogenic atrioventricular block on outcomes after congenital heart surgery

OBJECTIVE

The need for permanent pacemaker (PPM) for iatrogenic atrioventricular block (AVB) after congenital heart surgery is approximately 1%. We aimed to evaluate the long-term outcomes of patients with PPM for iatrogenic AVB and compare them with patients with an optimal repair (trivial/no residual) Residual Lesion Score (RLS) Class 1 repair without PPM need.

METHODS

We reviewed 183 patients discharged with PPM for iatrogenic AVB from 2011 to 2022. Patients who survived to discharge with >30 days of follow-up were matched 1:1 with a cohort of patients categorized as RLS Class 1 on the basis of fundamental diagnosis and primary procedure.

RESULTS

Median age at PPM placement was 1.4 years (interquartile range, 4.3 months to 3.9 years). The cumulative incidence of moderate or greater ventricular dysfunction at 1 year and 5 years was 11% and 18% in patients with PPM, respectively, compared with 3% and 7% in patients categorized as RLS Class 1 (subdistribution hazard ratio, 2.6; 95% confidence interval, 1.2-6.1; P = .022). Independently, patients with PPM with hypoplastic left heart syndrome (P = .027) and who had undergone Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Mortality Category 5 procedures (P = .033) were at greater risk of ventricular dysfunction. Transplant-free survival at 1 year and 5 years was 94% and 89% in patients with PPM, respectively, compared with 98% and 97% in patients categorized as RLS Class 1 (P = .044). In addition, patients with PPM with palliated circulation had significantly lower transplant-free survival (P < .001).

CONCLUSIONS

Compared with patients with an optimal repair without PPM, patients with PPM for iatrogenic AVB are at greater risk of developing moderate or greater ventricular dysfunction and have lower transplant-free survival.

A leadless pericardial pacemaker

BACKGROUND

Cardiac pacemakers have complications related to long pacemaker leads, subcutaneous pockets, and endovascular hardware.

OBJECTIVE

We report on the development of a leadless micropacemaker for percutaneous implantation into the pericardial space.

METHODS

Percutaneous implantations of a micropacemaker system were performed in 15 pigs through subxiphoid access to the pericardial space. In our concept phase, 10 implants were performed with iterative changes to the design and implantation techniques until a design was reached for a viable device. In the study phase, a viable device was implanted in 5 pigs and observed during 8 weeks.

RESULTS

At the completion of the concept phase, a prototype micropacemaker device was fabricated that met 3 mandatory system requirements: can be safely and reproducibly implanted percutaneously into the pericardial space; does not migrate after implantation; and successfully captures the myocardium at implantation and during long-term follow-up (up to 8 weeks). The prototype device was successfully and safely implanted into all 5 pigs in the study phase. These 5 animals survived to the 8-week end point without complications. Ventricular capture threshold calculations at implantation were a median 0.43 V at 0.4 ms (range, 0.05-0.75 V at 0.4 ms). At 8 weeks of follow-up, median capture thresholds were 2.8 V at 0.4 ms (total range, 2.2-7.1 V).

CONCLUSION

A novel pericardial micropacemaker system allows minimally invasive implantation of a leadless cardiac pacemaker without entering the vascular space. We provide proof of concept of this design with encouraging follow-up data.

Cardiac Resynchronization Therapy for Pacing-Related Dysfunction Post Cardiac Surgery in Neonates

An infant with DiGeorge syndrome, multiple comorbidities, and truncus arteriosus type II underwent repair complicated by heart block necessitating placement of a dual-chamber bipolar pacing system with right ventricular leads and subsequent resynchronization with placement of left ventricular apical pacing leads. Resynchronization therapy improved QRS duration from 180 ms to 100 ms and ejection fraction from 25% to 54% over the course of 4 weeks with gradual return to normal function and eventual discharge.

Conduction System Pacing in Pediatrics and Congenital Heart Disease, a Single Center Series of 24 Patients

His-bundle pacing has demonstrated feasibility in numerous adult studies to reverse and prevent pacing-induced cardiomyopathy, however, is met with higher capture thresholds with deployment sheaths designed for adults with his-bundles in the typical location. To describe 24 pediatric and adult congenital patients post-physiologic pacing. Patients at the University of Minnesota Masonic Children's Hospital with congenital complete heart block or congenital heart disease and atrioventricular block presented for pacemaker placement between November 2019 and January 2021. Twenty-four patients had attempted his-bundle placement using either Medtronic's C315 or C308 sheaths and 3830 leads except for 3 patients who had Boston Scientific's His system with the Shape 3 sheath and 7842 leads. Twenty-four total patients underwent physiologic pacing (23 his-bundle, 13 female, 11 male) with median age of 14 years (range 8-39 years) with median weight of 51 kg (range 21.2-81 kg) with five right-sided implants performed. Twelve patients had congenital heart disease including atrioventricular canal defects, tetralogy of Fallot, and ventricular septal defect repairs (nine patients with ventricular septal defect repairs). Twelve patients had selective His-bundle pacing (six with congenital heart disease). Median threshold to capture was 0.5 V at 0.4 ms (range 0.4 to 1.1 V at 0.4 ms), impedance 570 ohms (range 456-1140 ohms), and sensing median of 9.7 mV (range 1.5-13.8 mV if present). The median follow-up time was 610 days (range 240-760 days). No complications occurred peri-procedurally or during follow-up. His-bundle pacing is feasible in pediatric and congenital heart disease patients.

Updates in Arrhythmia Management in Adult Congenital Heart Disease

Arrhythmias are highly prevalent in adults with congenital heart disease. For the clinician caring for this population, an understanding of pathophysiology, diagnosis, and management of arrhythmia is essential. Herein we review the latest updates in diagnostics and treatment of tachyarrhythmias and bradyarrhythmias, all in the context of congenital anatomy, hemodynamics, and standard invasive palliations for congenital heart disease.

Left ventricular apical pacing-induced heart failure in a child after congenital heart surgery: a case report

Background

Left ventricular apical pacing (LVAP) is considered to preserve left ventricular (LV) systolic function in both patients with and without congenital heart disease. However, sporadic LVAP-associated cardiac dysfunction in children with complex structural heart disease was recently reported. We present the case of a 2.5-year-old child with complex congenital heart disease and LVAP-induced cardiomyopathy.

Case summary

Corrective surgery for double outlet right ventricle, subpulmonary ventricular septal defect, and transposition of the great arteries was done at the age of 1.5 months. Late complete atrioventricular block occurred, necessitating VVI pacemaker insertion with LV apical epicardial leads. He presented with heart failure and dilated cardiomyopathy 1.5 years after pacemaker insertion and required persistent circulatory support with intravenous inotropes. Speckle tracking echocardiography identified an important LV apical to basal dyssynchrony. After excluding any coronary artery involvement, cardiac resynchronization therapy was performed. Speckle tracking echocardiography guided lead placement resulted in improved LV contraction synchrony. Cardiac function recovered progressively in combination with oral heart failure medication and is almost normal at 10-month follow-up.

Discussion

Right ventricular pacing is a well-known cause of pacing-induced cardiomyopathy. The LV apex and LV free wall are thought to be most optimal locations for ventricular pacing in children. However, LVAP can also be the cause of a pacing-induced cardiomyopathy and decreased systolic LV function in children with complex congenital heart disease due to lack of LV contraction synchrony. Cardiac resynchronization therapy can reverse this LV dysfunction and remodelling.

Longitudinal echocardiographic parameters before and after pacemaker placement in congenital complete heart block

BACKGROUND

Congenital complete heart block (CCHB) is seen in 1:15,000-1:20,000 live births, with risk of left ventricular (LV) dysfunction or dilated cardiomyopathy in 7%-23% of subjects.

OBJECTIVE

The purpose of this study was to investigate serial changes in LV size and systolic function in paced CCHB subjects to examine the effect of time from pacemaker on echocardiographic parameters.

METHODS

Single-center retrospective cohort analysis of paced CCHB subjects was performed. Echocardiographic data were collected before and after pacemaker placement. Linear mixed effect regression of left ventricular end-diastolic dimension (LVEDD) z-score, left ventricular shortening fraction (LVSF), and left ventricular ejection fraction (LVEF) was performed, with slopes compared before and after pacemaker placement.

RESULTS

Of 114 CCHB subjects, 52 had echocardiographic data before and after pacemaker placement. Median age at CCHB diagnosis was 0.6 [interquartile range 0.0-3.5] years; age at pacemaker placement 3.4 [0.5-9.0] years; and pacing duration 10.8 [5.2-13.7] years. Estimated LVEDD z-score was 1.4 at pacemaker placement and decreased -0.08 per year (95% confidence interval [CI] -0.12 to -0.04; P = .002) to 0.2 (95% CI -0.3 to +0.3) 15 years postplacement. Estimated LVSF decreased -1.1% per year (95% CI -1.7% to -0.6%; P <.001) from 6 months prepacemaker placement to 34% (95% CI 32%-37%) 4 years postplacement. There was no significant change in LVSF between 4 and 15 years postplacement. Estimated LVEF did not change significantly after pacemaker placement, with estimated LVEF 59% (95% CI 55%-62%) 15 years postplacement.

CONCLUSION

In 52 paced CCHB subjects, estimated LVEDD z-score decreased significantly after pacemaker placement, and estimated LVSF and LVEF remained within normal limits at 15 years postpacemaker placement.

New Guidelines of Pediatric Cardiac Implantable Electronic Devices: What Is Changing in Clinical Practice?

Guidelines are important tools to guide the diagnosis and treatment of patients to improve the decision-making process of health professionals. They are periodically updated according to new evidence. Four new Guidelines in 2021, 2022 and 2023 referred to pediatric pacing and defibrillation. There are some relevant changes in permanent pacing. In patients with atrioventricular block, the heart rate limit in which pacemaker implantation is recommended was decreased to reduce too-early device implantation. However, it was underlined that the heart rate criterion is not absolute, as signs or symptoms of hemodynamically not tolerated bradycardia may even occur at higher rates. In sinus node dysfunction, symptomatic bradycardia is the most relevant recommendation for pacing. Physiological pacing is increasingly used and recommended when the amount of ventricular pacing is presumed to be high. New recommendations suggest that loop recorders may guide the management of inherited arrhythmia syndromes and may be useful for severe but not frequent palpitations. Regarding defibrillator implantation, the main changes are in primary prevention recommendations. In hypertrophic cardiomyopathy, pediatric risk calculators have been included in the Guidelines. In dilated cardiomyopathy, due to the rarity of sudden cardiac death in pediatric age, low ejection fraction criteria were demoted to class II. In long QT syndrome, new criteria included severely prolonged QTc with different limits according to genotype, and some specific mutations. In arrhythmogenic cardiomyopathy, hemodynamically tolerated ventricular tachycardia and arrhythmic syncope were downgraded to class II recommendation. In conclusion, these new Guidelines aim to assess all aspects of cardiac implantable electronic devices and improve treatment strategies.

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.

Epicardial Devices in Pediatrics and Congenital Heart Disease

Epicardial cardiac implantable electronic device implant remains a common option in pediatric patients and certain patients with congenital heart disease due to patient size, complex anatomy, residual intracardiac shunts, and prior surgery precluding transvenous implant. Advantages include the lack of thromboembolic and vascular risks and ability to implant during concomitant surgery. Significant disadvantages include the occurrence of lead dysfunction that can result in bradycardia events in pacemaker patients, inappropriate shocks in implantable cardiac defibrillator patients, and overall a more invasive procedure.

Translation of Tools and Techniques from the Adult Electrophysiology World to Pediatric Cardiac Implantable Electronic Devices

This article reviews various opportunities to translate established and novel tools and techniques used in adult electrophysiology to pediatrics and the adult congenital heart disease population. There is a specific focus on preoperative management of special population, implantation techniques, and postoperative programming of devices.

Lead Management in Patients with Congenital Heart Disease

Pediatric patients with congenital heart disease present unique challenges when it comes to cardiac implantable electronic devices. Pacing strategy is often determined by patient size/weight and operator experience. Anatomic considerations, including residual shunts, anatomic obstructions and barriers, and abnormalities in the native conduction system, will affect the type of CIED implanted. Given the young age of patients, it is important to have an "eye on the future" when making pacemaker/defibrillator decisions, as one can expect several generator changes, lead revisions, and potential lead extractions during their lifetime.

Pacing in Pediatric Patients with Postoperative Atrioventricular Block

Surgery for congenital heart disease may compromise atrioventricular (AV) nodal conduction, potentially resulting in postoperative AV block. In the majority of cases, AV nodal function recovers during the early postoperative period and may only require short-term pacing support, typically provided via temporary epicardial wires. Permanent pacing is indicated when the postoperative AV block persists for more than 7 to 10 days due to the risk of mortality if a pacemaker is not implanted. Although there is a subset of patients who may have late recovery of AV nodal function, those with continued postoperative AV block will need lifelong pacing therapy.

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.

Leadless epicardial pacing at the left ventricular apex: an animal study

AIMS

State-of-the-art pacemaker implantation technique in infants and small children consists of pace/sense electrodes attached to the epicardium and a pulse generator in the abdominal wall with a significant rate of dysfunction during growth, mostly attributable to lead failure. In order to overcome lead-related problems, feasibility of epicardial implantation of a leadless pacemaker at the left ventricular apex in a growing animal model was studied.

METHODS AND RESULTS

Ten lambs (median body weight 26.8 kg) underwent epicardial implantation of a Micra transcatheter pacing system (TPS) pacemaker (Medtronic Inc., Minneapolis, USA). Using a subxyphoid access, the Micra was introduced through a short, thick-walled tube to increase tissue contact and to prevent tilting from the epicardial surface. The Micra's proprietary delivery system was firmly pressed against the heart, while the Micra was pushed forward out of the sheath allowing the tines to stick into the left ventricular apical epimyocardium. Pacemakers were programmed to VVI 30/min mode. Pacemaker function and integrity was followed for 4 months after implantation. After implantation, median intrinsic R-wave amplitude was 5 mV [interquartile range (IQR) 2.8-7.5], and median pacing impedance was 2235 Ω (IQR 1725-2500), while the median pacing threshold was 2.13 V (IQR 1.25-2.9) at 0.24 ms. During follow-up, 6/10 animals had a significant increase in pacing threshold with loss of capture at maximum output at 0.24 ms in 2/10 animals. After 4 months, median R-wave amplitude had dropped to 2.25 mV (IQR 1.2-3.6), median pacing impedance had decreased to 595 Ω (IQR 575-645), and median pacing threshold had increased to 3.3 V (IQR 1.8-4.5) at 0.24 ms. Explantation of one device revealed deep penetration of the Micra device into the myocardium.

CONCLUSION

Short-term results after epicardial implantation of the Micra TPS at the left ventricular apex in lambs were satisfying. During mid-term follow-up, however, pacing thresholds increased, resulting in loss of capture in 2/10 animals. Penetration of one device into the myocardium was of concern. The concept of epicardial leadless pacing seems very attractive, and the current shape of the Micra TPS makes the device unsuitable for epicardial placement in growing organisms.

Emergency pacing via the umbilical vein of a neonate with congenital complete atrioventricular block: a report of two cases

We report two cases of successful emergency pacing via the umbilical vein in neonates with congenital complete atrioventricular block. The first patient, a neonate with normal cardiac anatomy, underwent emergency temporary pacing via the umbilical vein under echocardiographic guidance. The patient underwent permanent pacemaker implantation on postnatal day 4. The second patient, a neonate with heterotaxy syndrome, underwent emergency temporary pacing through the umbilical vein under fluoroscopic guidance. The patient underwent permanent pacemaker implantation on postnatal day 17.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Left ventricular endocardial activation maps during right ventricular pacing in pediatric patients

BACKGROUND

Cardiac pacing from right ventricular (RV) sites may cause electromechanical ventricular dyssynchrony. Invasive and noninvasive mapping studies showed left ventricular (LV) activation sequence in adults. Aim of this study was to seek out the LV endocardial activation (LVEA) in pediatric patients who underwent RV pacing.

METHODS

Single-center, prospective study conducted on pediatric patients who underwent left sided catheter ablation of accessory pathways with the Carto Univu mapping system. After successful ablation procedures, LVEA was recorded by the ablation catheter during sinus rhythm (SR) and during para-hisian (PHP), midseptum (MSP), and apical (RVAP) pacing.

RESULTS

Seventeen patients, 13 males, aged 12 (10-15) years, registered LV activation maps and times (LVAT). SR showed significantly shorter LVAT than during pacing. LVAT of PHP was shorter than MSP, while there were not significant differences among PHP and MSP versus RVAP. In SR initial LV endocardial activation occurred in two midseptum sites, inferior-posterior and superior-anterior. During PHP, initial activation occurred at parahisian basal septum, rapidly followed by midseptum as in SR. During MSP and RVAP initial activation occurred at midseptum and apex, respectively. From all initial sites, the excitation spreads toward the base of the lateral LV free wall. A mild linear correlation was found between QRS duration and LVAT for MSP and for PHP.

CONCLUSIONS

In pediatric patients LVEA maps during RV pacing showed that the shortest LVAT was obtained with PHP. The LV activation pattern seemed similar in sinus rhythm, PHP and MSP, from midseptum to LV lateral base.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Advancing the science of management of arrhythmic disease in children and adult congenital heart disease patients within the last 25 years

This review article reflects how publications in EP Europace have contributed to advancing the science of management of arrhythmic disease in children and adult patients with congenital heart disease within the last 25 years. A special focus is directed to congenital atrioventricular (AV) block, the use of pacemakers, cardiac resynchronization therapy devices, and implantable cardioverter defibrillators in the young with and without congenital heart disease, Wolff-Parkinson-White syndrome, mapping and ablation technology, and understanding of cardiac genomics to untangle arrhythmic sudden death in the young.

Natural History of Nonsurgical Complete Atrioventricular Block in Children and Predictors of Pacemaker Implantation

BACKGROUND

Data on the natural history of complete atrioventricular block (CAVB) in children are scarce, and criteria for pacemaker (PM) implantation are based on low levels of evidence.

OBJECTIVES

This study aimed to evaluate the natural course and predictors of PM implantation in a nationwide cohort of pediatric patients with nonsurgical CAVB.

METHODS

All children with CAVB in the absence of structural heart disease presenting from 1977 to 2016 were retrospectively identified, yielding 95 subjects with a mean age of 4.05 years at the first presentation with a follow-up median of 0.80 years (IQR: 0.02-6.82 years). PM implantation was performed according to the available guidelines. Serial 24-hour Holter recordings and echocardiograms were reviewed. Predictors of PM implantation performed >1 month after the first presentation were evaluated.

RESULTS

The minimum and mean 24-hour heart rates and maximum RR intervals had a nonlinear correlation with age (P < 0.0001 for all). The left ventricular (LV) size was moderately increased, and the shortening fraction was normal in the majority throughout follow-up. PM implantation was performed in 62 patients (65.3%) reaching guideline criteria. The mean 24-hour heart rate at presentation was a predictor of subsequent PM implantation (HR: 0.938; 95% CI: 0.894-0.983; P = 0.003 per unit increase) regardless of age at presentation. Patients presenting with a mean 24-hour heart rate >58 beats/min (>75th percentile) had a high probability of freedom from PM within the subsequent 5 years (91.7% vs 44.4%; P < 0.001).

CONCLUSIONS

Pediatric patients with CAVB showed an age-dependent decrease in heart rate, moderate LV dilation, and preserved LV function. The probability of subsequent PM implantation could be predicted by the heart rate profile at presentation, defining a low-risk group and allowing for individualized follow-up.

Pediatric Epicardial Devices: Early and Midterm Outcomes

BACKGROUND

Lead performance is suboptimal in young patients and a main cause of device system failure. Our objective was to assess early and midterm outcomes after epicardial device implantation in a contemporary pediatric cohort.

METHODS

A total of 116 consecutive pediatric patients underwent 137 epicardial device implantations from 2010 to 2019. Forty pacemakers and 97 implantable cardioverter defibrillators (ICDs) were implanted. Lead failure was defined as leads repaired, replaced, or abandoned due to fracture, dislodgement, or dysfunction. Freedom from device system failure was determined using Kaplan-Meier analysis.

RESULTS

Mean age at implantation was 10 ± 5 years, 46 (34%) were younger than 8 years old, 41 (30%) had prior cardiac surgery, and 38 (28%) had prior devices. Main indications were acquired heart block (17/40 [43%]), sinus node dysfunction (14/40 [35%]), and congenital heart block (7/40 [18%]) for pacemakers, and hypertrophic cardiomyopathy (46/97 [47%]), long QT syndrome (31/97 [32%]), and ventricular arrhythmia (17/97 [18%]) for ICDs. There were no early deaths. Three-year freedom from device system failure was 80% (95% CI 73%, 88%) for all patients and 88% (95% CI 79%, 99%) for patients <8 years old. Device system failure causes included lead fracture (20/34 [59%]), lead dysfunction (5/34 [15%]), lead dislodgement (5/34 [15%]), infection (3/34 [9%]), and pericarditis (1/34 [3%]). Reintervention was required in 26/34 (76%) device system failures.

CONCLUSIONS

Epicardial device implantation is safe, shows acceptable midterm outcomes in children, and is an effective option in patients younger than 8 years old. Close device surveillance continues to be essential to detect lead failure early and ensure timely reintervention.

Long-term outcomes of pacemaker implantation in children with univentricular versus complex biventricular surgical repair

Objective

Pacing in a univentricular circulation has been associated with worsened outcomes. We investigated the long-term outcomes of pacing in children with a univentricular circulation compared to a complex biventricular circulation. We also identified predictors of adverse outcomes.

Methods

A retrospective study of all children with major congenital heart disease who underwent pacemaker implantation under the age of 18 years between November 1994 and October 2017.

Results

Eighty-nine patients were included; 19 with a univentricular and 70 with a complex biventricular circulation. A total of 96% of pacemaker systems were epicardial. Median follow up was 8.3 years. The incidence of adverse outcome was similar between the two groups. Five (5.6%) patients died and two (2.2%) underwent heart transplantation. Most adverse events occurred within the first 8 years after pacemaker implantation. Univariate analysis identified five predictors of adverse outcomes in the patients in the biventricular but none in the univentricular group. The predictors of adverse outcome in the biventricular circulation were a right morphologic ventricle as the systemic ventricle, age at first congenital heart disease (CHD) operation, number of CHD operations, and female gender. The nonapical lead position was associated with a much higher risk of an adverse outcome.

Conclusions

Children with a pacemaker and a complex biventricular circulation have similar survival to the ones with a pacemaker and a univentricular circulation. The only modifiable predictor was the epicardial lead position on the paced ventricle, emphasizing the importance of apical placement of the ventricular lead.

Ventricular Functional Analysis in Congenital Complete Heart Block Using Speckle Tracking: Left Ventricular Epicardial Compared to Right Ventricular Septal Pacing

BACKGROUND

Chronic right ventricular (RV) apical pacing in patients with congenital complete atrioventricular block (CCAVB) is associated with left ventricle (LV) dyssynchrony and dysfunction. Hence, alternative pacing sites are advocated. The aim of this study was to compare LV function using STE in selected patients with LV epicardial pacing (LVEp) vs. RV transvenous pacing (RVSp).

METHODS

This was a single-center, retrospective study in patients with CCAVB who underwent permanent pacemaker implant at age ≤ 18 years. Age- and gender-matched patients with a normal heart anatomy and function served as the control group. LV function was comprehensively assessed by conventional 2D Echocardiography and speckle-tracking echocardiography (STE).

RESULTS

We included 24 patients in the pacemaker group [27.6% male, mean age of 17.1 at last follow-up, follow-up duration of 8.7 years, RVSp (n = 9; 62.5%)] compared to 48 matched healthy controls. Shortening fraction (SF) and ejection fraction (EF) were normal and similar between cases and controls. However, STE detected abnormal LV function in the pacemaker group compared to controls. The former demonstrated lower/abnormal, Peak Longitudinal Strain myocardial (PLS Myo) [- 12.0 ± 3.3 vs. - 18.1 ± 1.9, p < 0.001] and Peak Longitudinal Strain endocardial (PLS endo) [- 16.1 ± 4.1 vs. 1.7 ± 1.7, p < 0.001]. STE parameters of LV function were significantly more abnormal in LVEp vs. RVSp subgroup as demonstrated by lower values for PLS Myo (- 10.1 ± 3.2 vs. - 13.1 ± 2.9, p = 0.03) and PLS Endo (- 13.8 ± 4.4 vs. - 17.5 ± 3.3, p = 0.03).

CONCLUSION

STE was more sensitive in detecting subtle differences in LV function relative to standard conventional 2D echocardiography (SF and EF) in selected patients with CCAVB and a permanent pacemaker. Furthermore, STE demonstrated that transvenous RV septal pacing was associated with better LV systolic function preservation than LV epicardial pacing for comparable post-implant intervals.

Conduction system pacing in pediatric and congenital heart disease

Conduction system pacing (CSP) has evolved rapidly to become the pacing method of choice for many adults with structurally normal hearts. Studies in this population have repeatedly demonstrated superior hemodynamics and outcomes compared to conventional pacing with the recruitment of the native conduction system. Children and patients with congenital heart disease (CHD) are also likely to benefit from CSP but were excluded from original trials. However, very recent studies have begun to demonstrate the feasibility and efficacy of CSP in these patients, with growing evidence that some outcomes may be superior in comparison to conventional pacing techniques. Concerns regarding the technical challenges and long-term lead parameters of His Bundle Pacing (HBP) have been overcome to many extents with the development of Left Bundle Branch Area Pacing (LBBAP), and both techniques are likely to play an important role in pediatric and CHD pacing in the future. This review aims to assimilate the latest developments in CSP and its application in children and CHD patients.

Histological finding of maternal antibody-associated congenital heart block accompanied by large atrial septal defect and severe cardiac dysfunction

Cardiac dysfunction commonly occurs in congenital heart block associated with maternal anti-SSA antibodies, especially after pacemaker implantation. We report the case of a 4-year-old girl with antibody-associated congenital heart block and a large secundum atrial septal defect who presented with significant cardiac dysfunction 4 years after pacemaker implantation. Histological findings were useful for determining the course of treatment and perioperative risk of intracardiac repair.

Impact and Modifiers of Ventricular Pacing in Patients With Single Ventricle Circulation

BACKGROUND

Palliation of the single ventricle (SV) circulation is associated with a burden of lifelong complications. Previous studies have identified that the need for a permanent ventricular pacing system (PPM_v) may be associated with additional adverse long-term outcomes.

OBJECTIVES

The goal of this study was to quantify the attributable risk of PPM_v in patients with SV, and to identify modifiable risk factors.

METHODS

This international study was sponsored by the Pediatric and Congenital Electrophysiology Society. Centers contributed baseline and longitudinal data for functionally SV patients with PPM_v. Enrollment was at implantation. Controls were matched 1:1 to PPM_v subjects by ventricular morphology and sex, identified within center, and enrolled at matched age. Primary outcome was transplantation or death.

RESULTS

In total, 236 PPM_v subjects and 213 matched controls were identified (22 centers, 9 countries). Median age at enrollment was 5.3 years (quartiles: 1.5-13.2 years), follow-up 6.9 years (3.4-11.6 years). Median percent ventricular pacing (Vp) was 90.8% (25th-75th percentile: 4.3%-100%) in the PPM_v cohort. Across 213 matched pairs, multivariable HR for death/transplant associated with PPM_v was 3.8 (95% CI 1.9-7.6; P < 0.001). Within the PPM_v population, higher Vp (HR: 1.009 per %; P = 0.009), higher QRS z-score (HR: 1.19; P = 0.009) and nonapical lead position (HR: 2.17; P = 0.042) were all associated with death/transplantation.

CONCLUSIONS

PPM_v in patients with SV is associated with increased risk of heart transplantation and death, despite controlling for increased associated morbidity of the PPM_v cohort. Increased Vp, higher QRS z-score, and nonapical ventricular lead position are all associated with higher risk of adverse outcome and may be modifiable risk factors.

To go left or right? Driving towards the best direction in paediatric pacing

BACKGROUND

Permanent pacing in children with isolated congenital complete atrioventricular block may cause left ventricular dysfunction. To prevent it, alternative pacing sites have been proposed: left ventricular epicardial or selective right ventricular endocardial pacing.

AIMS

To compare the functional outcome (left ventricular systolic function and synchrony) in paediatric patients with congenital complete atrioventricular block and left ventricular apical epicardial or right ventricular transvenous mid-septal pacing.

METHODS

Retrospective study. Epicardial leads were implanted by standard surgical technique, transvenous leads by 3D electroanatomic mapping systems. 3D mapping acquired 3D right ventricular local pacing map and defined the narrowest paced QRS site. 3D mapping guided screw-in bipolar leads on that ventricular site. Electrocardiogram (ECG) (QRS duration) and echocardiographic data (synchrony: interventricular mechanical delay, septal to posterior wall motion delay, systolic dyssynchrony index; contractility: global longitudinal strain, ejection fraction) were recorded. Data are reported as median [interquartile ranges]. p < 0.05 was significant.

RESULTS

There were 19 transvenous systems (age 8.8 [6-14] years; right ventricular mid-septum) and 17 epicardial systems (0.04 [0.001-0.6] years; left ventricular apex). Post-implantation QRS significantly widened either in endocardial or in epicardial patients. Most patients reached 4-year follow-up. One-year and 4-year ejection fraction and global longitudinal strain were mostly within normal limits and did not show significant differences between the two groups and between the same endocardial/epicardial group. Synchrony parameters were within normal limits in the two groups.

CONCLUSIONS

Left ventricular apical epicardial pacing and 3D mapping-guided right ventricular mid-septal pacing preserved left ventricular contractility and synchrony in children and adolescents with congenital complete atrioventricular block at short-/mid-term follow-up, without relevant significant differences between the two groups.

Cardiac Implantable Electronic Devices in the Fontan Patient

As a result of remarkable progress in operative techniques and cardiology care during childhood, Fontan patients continue to age and require team-based multidisciplinary expertise to manage complications encountered in adulthood. They face particular challenges in terms of altered hemodynamic stressors, cardiac and hepatic failure, and arrhythmias. Arrhythmias in Fontan patients are highly prevalent and associated with underlying anatomy, surgical technique, and postoperative sequelae. Diagnostic tools, treatments, and device strategies for arrhythmias in Fontan patients should be adapted to the specific anatomy, type of surgical repair, and clinical status. Great strides in our understanding of arrhythmia mechanisms, options and techniques to obtain access to relevant cardiac structures, and application of both old and new technologies have contributed to improving cardiac implantable electronic device (CIED) therapies for this unique population. In this state-of-the-art review, we discuss the various arrhythmias encountered in Fontan patients, their diagnosis, and options for treatment and prevention, with a focus on CIEDs. Throughout, access challenges particular to the Fontan circulation are considered. Recently developed technologies, such as the sub-cutaneous implantable cardioverter defibrillator carry the potential to be transformative but require awareness of Fontan-specific issues. Moreover, new leadless pacing technology represents a promising strategy that may soon become applicable to Fontan patients with sinus node dysfunction. CIEDs are essential tools in managing Fontan patients but the complex clinical scenarios that arise in this patient population are among the most challenging for the congenital electrophysiologist.

Preliminary study on left bundle branch area pacing in children:clinical observation of 12 cases

OBJECTIVE

To explore the safety and feasibility of left bundle branch area pacing (LBBAP) in children.

METHODS

This study observed 12 children attempted LBBAP from January 2019 to January 2021 in the department of pediatric cardiology of Anzhen Hospital prospectively.Clinical data, pacing parameters, electrocardiograms, intracardiac electrograms, echocardiographic measurements and complications were recorded at implant and during follow-up.

RESULTS

The 12 patients aged between 3 and 14 years old and weighted from 13 to 48kg. Eleven patients were diagnosed with third-degree atrioventricular block and 1 patient (case 4) suffered from cardiac dysfunction due to right ventricular apical pacing (RVAP). Left bundle branch area pacing was successfully achieved in all patients with narrow QRS complexes and V₁ lead showed changes like right bundle branch block in the pacing electrocardiogram. Left ventricular ejection fraction in case 4 recovered on the 3rd day after LBBAP. The median of left ventricular end diastolic diameter Z score of the 12 patients decreased from 1.75 to1.05 3 months after implantation (p<0.05). The median of paced QRS duration was 103ms. The median of pacing threshold, R-wave amplitude and impedance were 0.85V, 15mV and 717Ω respectively and remained stable during follow-up. No complications such as loss of capture, lead dislodgement or septal perforation occurred.

CONCLUSIONS

Left bundle branch area pacing can be performed safely in children with narrow QRS duration and stable pacing parameters. Cardiac dysfunction caused by long-term RVAP can be corrected by LBBAP quickly. This article is protected by copyright. All rights reserved.

Incidence of Morbidity and Mortality in a Cohort of Congenital Complete Heart Block Patients Followed Over 40 Years

BACKGROUND

Congenital Complete Heart Block (CCHB), seen in 1:15,000-20,000 births, commonly requires pacemaker placement by young adulthood. There is limited understanding of cardiac morbidity and mortality.

OBJECTIVE

Determine long-term incidence of cardiac morbidity and mortality in subjects with CCHB and identify associated risk factors.

METHODS

Retrospective cohort analysis of subjects with CCHB at Children's Hospital of Philadelphia between 1976-2018. The primary outcome is a composite of death, left ventricular systolic dysfunction, heart failure, cardiomyopathy, or cardiac resynchronization therapy (CRT). Cox proportional hazard models assessed independent risk factors for the primary outcome and its components (death, heart failure and/or cardiomyopathy, CRT).

RESULTS

One-hundred-fourteen subjects (58% female, median age at last visit 15.2 years) were included. Eighty-eight (77%) underwent pacemaker implantation, with median age at placement 1.9 years (IQR, 0.1-8.0 years). Twenty-six subjects (23%) reached the primary outcome - 7 (6%) died and 14 (12%) were diagnosed with heart failure and/or cardiomyopathy. Median time from diagnosis to primary outcome was 3.1 years (IQR, 0.0-10.8 years). There were no significant associations between age at diagnosis less than 1-year (hazard ratio [HR]: 1.5, 95% CI 0.6-3.9), fetal diagnosis (HR: 2.3, 0.96-5.6), or maternal antibody positivity (HR: 2.4, 0.9-6.6) and the primary outcome. Fetal diagnosis had a higher associated hazard of heart failure and/or cardiomyopathy (HR: 4.5, 1.3-15.0).

CONCLUSION

In 114 subjects with CCHB, 23% reached the composite outcome of cardiac morbidity and mortality, with no significant association between age at diagnosis, fetal diagnosis, and maternal antibody status with composite cardiac morbidity and mortality.

Fortuitous Left Bundle Branch Area Pacing in a Small Child

Deep septal pacing is an emerging technique for physiologic pacing in adults. We report a case where left bundle capture was inadvertently achieved in a small child with routine lead deployment into a thin septum and discuss the potential feasibility of this technique for future study. (Level of Difficulty: Advanced.)

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Developed in collaboration with and endorsed by the Heart Rhythm Society (HRS), the American College of Cardiology (ACC), the American Heart Association (AHA), and the Association for European Paediatric and Congenital Cardiology (AEPC) Endorsed by the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS)

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Cardiac resynchronisation therapy in a pace-dependent infant with tetralogy of Fallot

We present the case of a 5-month-old infant with tetralogy of Fallot and congenital atrio-ventricular block that developed severe left ventricular dysfunction during apical left ventricular pacing, in which cardiac resynchronisation therapy was used as an emergency procedure due to persistent low cardiac output syndrome.

Simple is Complicated

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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.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consenus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology, (ACC) and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate follow-up in pediatric patients.