Three-dimensional electroanatomical mapping guided right bundle branch pacing in congenitally corrected transposition of great arteries

Conduction System Pacing in Children and Congenital Heart Disease

Permanent cardiac pacing in children with congenital complete atrioventricular block (CCAVB) and/or congenital heart disease (CHD) is challenging. Conduction system pacing (CSP) represents a novel pacing strategy aiming to preserve physiological ventricular activation. Patients with CCAVB or CHD are at high risk of developing pacing-induced cardiomyopathy with chronic conventional right ventricular myocardial pacing. CSP may be a valuable pacing modality in this particular setting because it can preserve ventricular synchrony. In this review, we summarise implantation techniques, the available clinical evidence and future directions related to CSP in CCAVB and CHD.

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.

Advances in cardiac pacing with leadless pacemakers and conduction system pacing

PURPOSE OF REVIEW

The field of cardiac pacing has undergone significant evolution with the introduction and adoption of conduction system pacing (CSP) and leadless pacemakers (LLPMs). These innovations provide benefits over conventional pacing methods including avoiding lead related complications and achieving more physiological cardiac activation. This review critically assesses the latest advancements in CSP and LLPMs, including their benefits, challenges, and potential for future growth.

RECENT FINDINGS

CSP, especially of the left bundle branch area, enhances ventricular depolarization and cardiac mechanics. Recent studies show CSP to be favorable over traditional pacing in various patient populations, with an increase in its global adoption. Nevertheless, challenges related to lead placement and long-term maintenance persist. Meanwhile, LLPMs have emerged in response to complications from conventional pacemaker leads. Two main types, Aveir and Micra, have demonstrated improved outcomes and adoption over time. The incorporation of new technologies allows LLPMs to cater to broader patient groups, and their integration with CSP techniques offers exciting potential.

SUMMARY

The advancements in CSP and LLPMs present a transformative shift in cardiac pacing, with evidence pointing towards enhanced clinical outcomes and reduced complications. Future innovations and research are likely to further elevate the clinical impact of these technologies, ensuring improved patient care for those with conduction system disorders.

A case report of upgrading to cardiac resynchronization therapy in a patient with congenitally corrected transposition of great arteries and dextrocardia

Background

Congenitally corrected transposition of the great arteries (CCTGA) is a rare congenital heart anomaly. Physiological correction may be associated with a long pre-symptomatic period in many patients and delayed accidental diagnosis. Additional related congenital malformations may increase the complexity of cardiac interventions.

Case summary

A 59-year-old man with known dextrocardia, situs viscerum inversus, and CCTGA was scheduled for upgrading of a dual-chamber pacemaker to cardiac resynchronization therapy to treat heart failure related to a progressive systolic dysfunction of the systemic right ventricle (RV). Because of the specific anatomy of this patient, the therapeutic procedure was complicated by the cannulation of the Marshall vein. Nevertheless, the left ventricular lead was successfully implanted into the coronary sinus lateral branch. At the 3-month follow-up, the patient remarkably reported a significant functional improvement, despite no favourable reverse remodelling of the systemic RV.

Discussion

Upgrade of a pacemaker to biventricular pacing was feasible in this patient, who had CCTGA and dextrocardia, which resulted in symptomatic improvement at follow-up. Pre-implant contrast cardiac computed tomography angiography was essential for visualizing the venous-specific anatomy in this patient, who suffered from congenital heart disease. Conduction system pacing represents a potential alternative for the patient to prevent or treat pacing-related heart failure.

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.