Over the past three decades, the life expectancy of patients with congenital heart disease (CHD) has increased due to advances in surgical techniques and clinical care [1]. Throughout life, CHD patients are at high risk for redo-surgery, not only for residual lesions, but also for acquired cardiovascular diseases such as coronary artery disease. The prevalence of both atrial and ventricular tachyarrhythmias in CHD patients undergoing redo-surgery may be considerable. As demonstrated in Fig. 1, atrial tachyarrhythmias, including atrial flutter (AFL) and atrial fibrillation (AF), occur in up to 60% of the patients with CHD [2] and are associated with significant morbidity and mortality [3]. In CHD patients, AF arises at a relatively younger age compared to patients without CHD and progresses more rapidly [4]. Ventricular tachyarrhythmias, although less common, can significantly increase the risk of sudden death in conditions like Tetralogy of Fallot (ToF). Overall, approximately 20% to 25% of late mortality in adult CHD patients is attributable to sudden cardiac events resulting from ventricular tachyarrhythmias (VTs) [5].

Technological and procedural advancements have transformed catheter ablation (CA) and surgical ablation (SA) into well-established rhythm-control therapies for tachyarrhythmias [6]. The effectiveness of CA in CHD patients is hampered by altered anatomy and complex arrhythmogenic substrates, induced by atrial volume or pressure overload, surgical scars and prosthetic materials. [2,5,7,8].

If CA fails in achieving rhythm-control, SA becomes an important treatment modality. Current guidelines endorse SA for patients with symptomatic tachyarrhythmias who are undergoing concomitant surgical repair and have tachyarrhythmia refractory to both antiarrhythmic drugs and CA [9,10].

Beyond treating existing tachyarrhythmias, there is growing interest in the potential for prophylactic SA during surgical cardiac repair. Currently, limited knowledge is available on (1) how to identify patients at risk for tachyarrhythmias, (2) what the outcome of prophylactic SA for specific CHD and tachyarrhythmia substrates are, and (3) what the overall risk-benefit ratio of incorporating prophylactic SA into surgical cardiac repair is [2].

The role of SA in tachyarrhythmia management has evolved significantly since its early applications. In 1968, Sealy and colleagues performed the first successful SA of a manifest accessory pathway (AP) [11]. Subsequent advancements in SA included epicardial and endocardial approaches to treat tachyarrhythmias such as atrioventricular reentrant tachycardia, atrioventricular nodal reentrant tachycardia, and VT. The Cox-Maze procedure, introduced in the late 1980s, was a pivotal advancement for treating AFL and AF. Initially performed using a ‘cut-and-sew’ technique, the procedure strategically created surgical atrial lesions to disrupt abnormal electrical circuits and prevent AF [12]. Over time, the Cox-Maze procedure evolved into multiple variations employing energy-based techniques like cryothermal or radiofrequency energy to enhance safety and effectiviness. These surgical variations highlight the continuous improvement of SA as a crucial treatment modality for managing tachyarrhythmias, particularly in patients with CHD [2,13–15].

The aim of this review is to critically discuss (1) the indications for surgical ablation, (2) which surgical ablation techniques are suitable for specific atrial tachyarrhythmias, (3) atrial tachyarrhythmias associated with specific CHD, (4) long-term outcomes of SA with CA in patients with various CHD and (5) the risk-benefit ratio of prophylactic arrhythmia surgery.

A comprehensive literature search was conducted using Embase, PubMed, Scopus, and Google Scholar to identify relevant articles published before August 2024. The search included keywords such as “surgical ablation”, “congenital heart disease”, “children”, “pediatric”, “supraventricular tachycardia”, “ventricular tachycardia”, and “arrhythmia”. Articles were selected based on their relevance, focusing on studies that reported the use of SA in both pediatric and adult populations with CHD. Only published articles with full text available online in English were included. Studies were excluded from analysis if they did not include CHD patients or solely focused on CA. Given that the introduction of the Cox-Maze procedure marked a pivotal change in SA techniques, studies published prior to 1989 were also excluded from analysis. No formal quality assessment was performed. A total of 24 articles were included in this review. Two independent reviewers reviewed the articles and extracted the data (Fig. 2).

SA is typically considered for CHD patients when factors like complex anatomy, multiple tachyarrhythmia substrates, patient age and size, or limited cardiac access make CA less effective or unfeasible [15]. Especially in very young patients, CA can be technically challenging and carries higher risks of complications such as heart block or coronary artery injury [15]. Furthermore, SA is useful in conditions like Ebstein’s Anomaly (EA), ToF, and other complex CHDs where tachyarrhythmias are a significant concern. The Cox-Maze procedure has proven to be particularly effective for treating AF in patients with complex CHD [15].

The decision to perform SA depends on the patient’s tachyarrhythmia severity, the specific congenital defect, and the associated risks [14,15]. On the other hand, preventive concomitant SA is performed when there is a known predisposition to future tachyarrhythmias caused by tissue damage including surgical scarring [5].

Successful outcomes of SA depend on thorough pre-operative assessments, including identifying APs and unveiling any inducible atrial tachyarrhythmias to lower the risk of postoperative tachyarrhythmias. When atrial tachyarrhythmias have a high probability of persisting despite hemodynamic improvement after surgical repair, integrating SA into the surgical procedure increases the likelihood of arrhythmia free survival.

The current recommendations for SA in adult patients with CHD are summarized in Table 1 [2,10]. These recommendations highlight the strategic use of SA alongside cardiac surgeries, tailored to individual risks and anatomical considerations to improve outcomes in CHD patients.

Contraindications for SA include severe comorbidities that increase surgical risks such as advanced heart failure or significant pulmonary hypertension [14]. Furthermore, the location of the ablation target can make SA significantly challenging or infeasible. For instance, APs of the left atrial (LA) free wall are notoriously difficult to reach surgically, especially in infants and small children [16].

Prophylactic arrhythmia surgery is not recommended for adults with CHD who face high surgical mortality risk due to ventricular dysfunction or major comorbidities, especially when extended cardiopulmonary bypass or cross-clamp times could worsen outcomes [2]. Similarly, empiric VT surgery is not advised for adults with CHD lacking clinical or inducible sustained VTs [5,9].

Careful patient selection and a thorough risk-benefit assessment are crucial when considering SA in CHD patients, especially in patients with complex CHD.

VTs in CHD patients commonly occur in those who have undergone surgical repairs, especially in ToF patients in whom prior ventriculotomies or ventricular septal defect closures induces arrhythmogenic substrates. In addition, the substrate in CHD patients is often increased by structural remodeling, such as scars or lesions induced by the high pressure and flow of echocardiographic jets [7].

Preoperative electrophysiological studies are crucial to map zones of conduction slowing, typically found between the tricuspid valve annulus and right ventricular outflow tract scar, or between the pulmonary valve annulus and ventricular septal defect patch. Ablation, using radiofrequency- or cryothermal energy is indicated primarily for monomorphic VT. Success rates vary widely, ranging from 50% to 90%, with long-term arrhythmia-free survivals. Postoperative electrophysiological studies in children and adults with CHD are recommended to assess VT inducibility, supporting decision making for implantable cardioverter-defibrillators [7,16].

According to Nevvazhay and collegues, ablation of VT is particularly beneficial in patients with ToF [27]. Monomorphic macroreentrant VT in ToF patients often arises from areas of myocardial fibrosis, creating anatomical isthmuses bordering reentrant circuits. Notably, the isthmus that is located between the pulmonary valve and the ventricular septal defect patch, is a critical region which is involved in most macroreentrant VTs. Given that pulmonary valve replacement can obscure this isthmus, preoperative electrophysiological studies and electroanatomical mapping are essential for identifying patients at high risk for inducible macroreentrant VTs. Intraoperative cryoablation of the critical isthmus can effectively disrupt potential reentrant wavelet propagation, thereby preventing recurrent VT episodes, reducing the need for future interventions, and ultimately lowering the risk of VT-related sudden cardiac death [27]. This highlights the importance of individualized ablation strategies in managing VTs in CHD patients, tailored to the specific anatomical and etiological factors.

Prophylactic SA during cardiac repairs targets potential arrhythmogenic substrates before they give rise to clinical tachyarrhythmias, thereby improving long-term outcomes and reducing the need for future interventions. However, prophylactic ablation is not without risks, and is associated with prolonged procedure time, increased cardiopulmonary bypass duration, and potential damage to conduction tissues that can result in complications like heart block or sinus node dysfunction [5,8].

Prophylactic ablation for VT is generally not recommended due to the risk of creating pro-arrhythmogenic lesions. However, in patients with ToF undergoing pulmonary valve replacement, intraoperative cryothermal ablation of specific isthmuses can be considered. These critical isthmuses are rendered inaccessible after surgical repair, making preemptive SA a potential strategy to mitigate future arrhythmia risk. ToF patients therefore represent a specific subgroup of CHD patients who might benefit from a prophylactic approach [27].

Furthermore, while prophylactic modified RA maze procedures are recommended for Fontan revisions, their role in primary Fontan procedures is less definitive, as trials have not shown a significant reduction in tachyarrhythmia risk with additional RA lesions during the initial lateral tunnel Fontan procedures.

Despite the lack of a standardized approach due to variability in lesion sets and patient populations, prophylactic arrhythmia surgery is gaining attention. Individualized strategies are critical, taking specific risks into account, such as atrial dilation, mitral valve disease, and previous surgical repairs, which are all associated with increased lifetime risk of tachyarrhythmias. Observational data suggest that atrial tachyarrhythmias, including AF, increase with age and time since surgery, underscoring the need for proactive, prophylactic treatment [2].

SA in CHD patients generally results in notable improvements in tachyarrhythmia-free survival and quality of life. However, the efficacy of these procedures vary, depending on the type of tachyarrhythmia, the specific congenital defect, and the timing of intervention.

While SA is effective in managing tachyarrhythmias in CHD patients, it is not without risks. Potential complications include stroke, renal failure and the need for pacemaker implantation. These risks are generally similar to those associated with CA, and the long-term benefits of SA often outweigh these potential complications [6].

One notable complication of the maze procedure is sinus node dysfunction, which can be mitigated by limiting prophylactic maze lines to areas away from the sinus node [8]. Ablation targeting APs in the septal region also carries an elevated risk of atrioventricular conduction block, particularly in young children, with an incidence of about 3% [14]. These potential complication highlights the need for close monitoring of the patient postoperatively as they may necessitate implantation of a pacemaker.

Most procedural risks are either related to adhesions from prior cardiac surgeries or ancillary techniques, such as general anesthesia, median sternotomy, and cardiopulmonary bypass, rather than the ablation itself, which is considered relatively low risk [35]. The advancements in minimally invasive surgery, which often eliminate the need for a sternotomy, significantly improve therapy outcomes, reducing recovery time and procedural risks [6,35]. These minimally invasive procedures may have substantial benefits for patient outcomes.

Long-term risks of SA include tachyarrhythmia recurrences, especially in patients with complex CHD or extensive surgical scarring. Patients may develop reentrant tachyarrhythmias due to incomplete lesion sets or the progression of their underlying heart disease [8]. Although recurrence rates for AF and VT are generally lower with SA compared to CA, they are not negligible, and frequent post-operative monitoring is crucial [6].

Overall, while SA involves certain risks, its long-term efficacy in patients with complex anatomy or those who have failed CA makes it a valuable treatment option. The decision between SA and CA should be based on the patient’s specific congenital defect, type of tachyarrhythmia, and overall risk profile.

The management of tachyarrhythmias in pediatric patients with CHD poses unique challenges due to the smaller size and ongoing development of the heart in the post-operative period. One major challenge is the technical difficulty of performing SA in small children, where the limited size of cardiac structures increases the risk of collateral damage to critical areas. This risk is particularly pronounced in neonates and infants, in whom achieving effective lesion sets without compromising vital structures is challenging [16,33,34].

Additionally, the presentation and progression of tachyarrhythmias in pediatric CHD patients varies considerably. Children with complex CHD, such as single ventricle physiology or ToF, may develop tachyarrhythmias at different stages of life. Surgical scars from previous operations can serve as substrates for reentrant tachyarrhythmias, further complicating rhythm control [2,8,15,31]. Moreover, recurrent tachyarrhythmias and multiple surgeries can have a significant psychological and emotional impact on both the child and their family members, often leading to considerable stress [7,8].

Overall, these factors underscore the complexity of managing tachyarrhythmias in the pediatric population and the importance of individualized care plans that address both the technical challenges and the broader impacts on patient and family well-being.

The field of SA for tachyarrhythmias in CHD is rapidly advancing, with several promising developments on the horizon. One key development is the refinement of hybrid procedures that combine the strengths of both surgical and catheter-based approaches. These hybrid techniques enable simultaneous access to both the epicardium and endocardium thereby maximizing the effectiveness of ablation. Especially in CHD patients with complex anatomies, the combination of simultaneous endocardial and epicardial access improves the accuracy of ablation [6]. A second key development is the shift towards more minimally surgical invasive techniques which offer new opportunities for incorporating SA to a larger patient population. Yet, open-heart surgery, while more invasive, provides direct access to areas of the heart that may be difficult to reach by less- or non-invasive approaches, enabling more comprehensive and potentially more effective ablation. As both the minimally invasive and open procedures continue to evolve, the balance between the two will play a critical role in optimizing treatment strategies for CHD patients.

Cardiac sympathetic denervation is a surgical option for VT, primarily reserved for patients with structurally normal hearts and drug refractory VTs. This procedure, involving the left sympathetic chain, reduces arrhythmia burden by targeting norepinephrine-containing vesicles in the stellate ganglion and associated nerves. Modifications to the procedure, such as sparing parts of the stellate ganglion or performing bilateral sympathectomy, have improved outcomes and minimized complications like Horner syndrome [36]. This technique may prove beneficial in the treatment of VT in CHD, however this still requires further investigation.

In summary, ongoing technical innovations improving (less invasive) SA procedures fuel optimalization of SA for CHD patients, addressing the challenges posed by complex anatomies and variable arrhythmogenic substrates, and hold the potential to significantly improve patient outcomes in the future.

In CHD patients in whom CA is unsuccessful or is deemed unfeasible, SA may play a pivotal role in optimizing clinical outcomes. Based on the current literature discussed in this review, an overview of the SA strategies for tachyarrhythmias associated with specific congenital heart defects is provided in Table 2.

SA for tachyarrhythmias in patients with CHD offers significant benefits, including the potential for long-term tachyarrhythmia control and improved quality of life. SA is indicated when CA fails, CA is unfeasible due to complex anatomy, multiple arrhythmia substrates, or small patient size, and when SA can be performed concomitantly to the corrective surgery to reduce the procedural burden. SA is currently underutilized in clinical practice, despite the potential it offers as a more comprehensive treatment in specific CHD populations. With approximately 3.5 times higher odds of achieving arrhythmia-free survival compared to CA, SA has been proven to be effective in treating tachyarrhythmias in CHD patients. To optimize outcomes, a patient-tailored approach, guided by the patient-specific anatomical and arrhythmic characteristics, is needed. As our understanding of arrhythmogenesis in CHD continues to grow, and as new mapping and ablation technologies emerge, the role of SA in treating arrhythmias in CHD patients is likely to expand, offering hope to a growing number of patients with challenging tachyarrhythmias.