Contemporary Outcomes of Supraventricular Tachycardia Ablation in Congenital Heart Disease

Case Report: Remote magnetic navigation and accessory pathways ablation in a single ventricle young adult with complex corrective surgeries

Supraventricular arrhythmias have become an increasingly significant contributor to the risk of mortality and morbidity in adults with complex congenital heart disease (CHD), especially in light of recent advances in palliative corrective surgeries. Because of their unique characteristics, they demand specific treatment approaches. While pharmaco-logical interventions are an option, they have limited effectiveness and may lead to side effects. Although performing radiofrequency ablation (RFA) can be exceptionally challenging in patients with complex CHD, due to particular vascular access and also modified anatomy, it has paved the way to enhance comprehension of the underlying mechanisms of supraventricular arrhythmias. This, in turn, enables the provision of improved therapies and, ultimately, an enhancement in the quality of life and symptom management for these patients. The purpose of this case report is to highlight the benefits of utilizing advanced technologies such as three-dimensional electro-anatomical mapping systems, remote magnetic navigation, and highly flexible mapping and ablation catheters during RFA in a young adult with complex congenital heart disease. Although he lacked venous connections to the right atrium (RA) due to multiple corrective surgeries we, remarkably, were capable to advance a decapolar deflectable diagnostic catheter inside the Fontan tunnel and from there to record and stimulate the RA. Successful ablation of two accessory pathways was achieved with no arrhythmia recurrence during follow-up.

Robotic magnetic-guided catheter ablation in patients with congenital heart disease: a systematic review and pooled analysis

BACKGROUND

Robotic magnetic navigation (RMN) has emerged as a potential solution to overcome challenges associated with catheter ablation of arrhythmias in patients with congenital heart disease (CHD).

OBJECTIVES

To assess safety and efficacy of RMNguided catheter ablation in patients with CHD.

DESIGN AND METHODS

A systematic review and pooled analysis was conducted on patients with CHD who underwent RMNguided catheter ablation. Random effects models were used to generate pooled estimates with the inverse variance method used for weighting studies.

RESULTS

Twentyfour nonoverlapping records included 167 patients with CHD, mean age 36.5 years, 44.6% female. Type of CHD was simple in 27 (16.2%), moderate in 32 (19.2%), and complex in 106 (63.5%). A total of 202 procedures targeted 260 arrhythmias, the most common being macroreentrant atrial circuits. The mean procedural duration was 207.5 minutes, with a mean fluoroscopy time of 12.1 minutes. The pooled acute success rate was 89.2% [95% CI (77.8%, 97.4%)]. Freedom from arrhythmia recurrence was 84.5% [95% CI (72.5%, 94.0%)] over a mean follow-up of 24.3 months. The procedural complication rate was 3.5% with no complication attributable to RMN technology.

CONCLUSION

RMN-guided ablation appears to be safe and effective across a variety of arrhythmia substrates and types of CHD.

PentaRay® Multielectrode Mapping Catheter for Atrial Tachyarrhythmia in Adults With Congenital Heart Disease

BACKGROUND

Ablation of atrial tachyarrhythmia in adults with congenital heart disease (ACHD) is challenging because of complex anatomy and high scar burden. We proposed that the addition of high-density mapping with the PentaRay® (Biosense Webster, Inc) mapping catheter (EAM+P) to 3-dimensional electroanatomic mapping (EAM) allows for rapid acquisition of high-resolution maps and shorter procedure times.

METHODS

In this single-center, retrospective cohort study of patients with ACHD who underwent atrial arrhythmia ablation, patients were divided those who underwent ablation with EAM and those who underwent ablation with EAM+P.

RESULTS

Fifteen ablations were performed in 13 patients using standard EAM, and 11 ablations were performed in 10 patients using EAM+P. There was no difference in mean age or complexity of congenital heart disease. The procedure duration was 1.5 times longer in the EAM than in the EAM+P group (P = .015). The dose area product was 12 times higher in the EAM than in the EAM+P group (P = .001). A higher number of venous access sites were used for EAM cases than for EAM+P cases (P = .008). Acute success rates of ablation and recurrence rates at 1 year were similar in the 2 groups. There were no procedure-related complications in either group.

CONCLUSION

This is the first study to evaluate the use of the PentaRay® high-density mapping catheter for ablation of atrial tachyarrhythmia in patients with ACHD. The use of the PentaRay® high-density mapping catheter results in shorter procedure time, decreased radiation exposure, and fewer venous access sites.

Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in Patients With Congenital Heart Disease

Atrioventricular (AV) nodal reentrant tachycardia represents the most common regular supraventricular arrhythmia in humans, and catheter ablation of the so called slow AV nodal pathway has been effectively performed for decades. In patients with congenital heart disease, a combination of different factors makes catheter ablation of AV nodal reentrant tachycardia substrate particularly challenging, including abnormal venous access to intracardiac structures, abnormal intracardiac anatomy, potentially deviant and often unpredictable sites of the specific conduction system, loss of traditional anatomic landmarks, and congenital cardiac surgery that may complicate the access to the AV nodal area. Published experiences have confirmed the efficacy and the relative safety of such procedures when performed by experts, but the risk of complications, in particular AV block, remains non-negligible. A thorough knowledge and understanding of anatomic and electrical specificities according to underlying phenotype are essential in addressing these complex cases. Considering the major consequences associated with AV block in patients with complex congenital heart disease, particularly those without low risk access for transvenous ventricular pacing (eg, single ventricle physiology or Eisenmenger syndrome), the individual risk-benefit ratio should be carefully evaluated. The decision to defer ablation may be the wisest approach in selected patients with either infrequent or hemodynamically tolerated arrhythmias, or when the location of the AV conduction pathways remains uncertain. This narrative review aims to synthetize existing literature on catheter ablation of AV nodal reentrant tachycardia in congenital heart disease, to present main features of common associated pathologies, and to discuss approaches to mapping and safely ablating the slow AV nodal pathway in challenging cases.

Tachyarrhythmias in Congenital Heart Diseases: From Ion Channels to Catheter Ablation

Major advances in pediatric cardiology in recent decades, especially surgical techniques, have resulted in an increasing number of patients with congenital heart disease (CHD) surviving to adulthood. This has generated new challenges, particularly with regards to the late onset of complex arrhythmias. Abnormal anatomy, surgical scarring, chronic hypoxemia, hemodynamic compromise, neuro-hormonal abnormalities, and genetic factors can all contribute to creating a unique substrate for arrhythmia development. This review attempts to synthesize the current state of knowledge spanning the spectrum from underlying mechanisms of arrhythmias in patients with congenital heart disease to current ablative strategies. We discuss existing knowledge gaps and highlight important areas for future research.

The First Evaluation of Remote Magnetic Navigation-Guided Pediatric Ventricular Arrhythmia Ablation

Catheter ablation (CA) is an important treatment option for ventricular arrhythmias (VA) in pediatric cardiology. Currently, various CA techniques are available, including remote magnetic navigation (RMN)-guided radiofrequency (RF) ablation. However, no studies evaluate RMN-guided ablative therapy outcomes in children with VA yet. This study aimed to compare procedural and long-term outcomes between RMN-guided and manual (MAN)-guided VA ablation in children. This single-center, retrospective study included all CA procedures for VA performed in children with or without structural heart disease from 2008 until 2020. Two study groups were defined by CA technique: RMN or MAN. Primary outcome was recurrence of VA. Baseline clinical, procedural and safety data were also evaluated. This study included 22 patients, who underwent 30 procedures, with a median age of 15 (IQR 14-17; range 1-17) years and a mean weight of 57 ± 20 kg. In total, 14 procedures were performed using RMN and 16 using MAN (22 first and 8 redo procedures). Regarding first procedures, recurrence rates were significantly lower in RMN compared to MAN (20% versus 67%, P = 0.029), at a mean follow-up of 5.2 ± 3.0 years. Moreover, fluoroscopy dosages were significantly lower in RMN compared to MAN [20 (IQR 14-54) versus 48 (IQR 38-62) mGy, P = 0.043]. In total, 20 patients (91%) were free of VA following their final ablation procedure. This is the first study to investigate the use of RMN in pediatric VA ablation. RMN showed improved outcomes compared to MAN, resulting in lower VA recurrence and reduced fluoroscopy exposure.

Contemporary Patients With Congenital Heart Disease: Uniform Atrial Tachycardia Substrates Allow for Clear Ablation Endpoints With Improved Long-Term Outcome

[Figure: see text].

High-definition mapping of the atria using a novel multipolar mapping catheter in patients with complex adult congenital heart disease

Background

The Advisor™ HD Grid Mapping Catheter (Abbott Technologies, Minneapolis, MN) has been recently introduced. Although the clinical use of HD Grid mapping catheter is well described in adults with no congenital heart disease, there is limited data on the feasibility of using the HD Grid multipolar catheter to create voltage and activation mapping in adults with congenital heart disease. The purpose of this study was to evaluate the safety and technical feasibility of using the Advisor™ HD Grid mapping catheter during the catheter ablation of atrial arrhythmias in adults with congenital heart disease. We included 6 consecutive adults with congenital heart disease suffering from atrial arrhythmias in our study. The HD Grid mapping catheter was used to perform voltage and activation mapping.

Results

Six patients with congenital heart diseases (d-TGA n = 1, Tricuspid atresia n = 1, atrioventricular defect repair n = 1, secundum atrial septal defect n = 1, double-inlet single-ventricle n = 1, Tetralogy of Fallot = 1); majority (84%) male, with the mean age was 35 ± 10 years included in our series. The mean ablation duration and the fluoroscopy time were 789 ± 433 and 502 ± 355 s, respectively. The mean radiation dose was 7.52 ± 9 milliGy/cm2. The HD Grid mapping catheter was used successfully for entire arrhythmia mapping in 5 out of 6 cases. During one procedure, HD Grid mapping catheter could not be used for the entire mapping due to suboptimal reach through baffle puncture. The acute success rate of ablation was 100% with no immediate complications.

Conclusions

The use of HD Grid mapping catheter is a safe and valuable adjunct to accurately create voltage and activation mapping in ACHD patients undergoing radiofrequency catheter ablation. However, a contact force-sensing ablation catheter should be considered in conjunction to supplement data acquisition in challenging anatomy and substrates.

Impact of specialized electrophysiological care on the outcome of catheter ablation for supraventricular tachycardias in adults with congenital heart disease: Independent risk factors and gender aspects

BACKGROUND

Limited data exist on the impact of gender and specialized care on the requirement of repeat treatment of supraventricular tachycardia (SVT) in adult patients with congenital heart disease (ACHDs).

OBJECTIVE

The study aimed to assess independent predictors of a combined end point of re-catheter ablation (CA) or cardioversion at 3 years of follow-up, including the impact of gender and specialized ACHD care.

METHODS

All ACHDs registered in a database of one of the largest German health insurers (≈9.2 million members) who underwent CA for SVT were analyzed.

RESULTS

Of 38,892 ACHDs 16 years or older, 485 (49.5% women; median age 58.4 years; interquartile range 42.1-70.8 years) underwent CA for SVT. Over 3-year follow-up, the number of yearly CA procedures increased significantly, particularly for atrial fibrillation (+195%) and atrial flutter (+108%). Moderate to severe complexity heart disease (odds ratio [OR] 1.66; P = .01), advanced age (OR 1.85 per year; P = .02), chronic kidney disease (OR 1.70; P = .01), and atrial fibrillation (OR 2.02; P = .002) emerged as independent predictors of retreatment. Retreatment was significantly less often performed if primary CA was carried out at a specialized CHD center (P = .009) in patients with moderate to severe complexity heart disease. Women treated in specialist centers had a 1.6-fold reduced risk of undergoing retreatment (P = .01).

CONCLUSION

CA for SVT is increasingly performed in ACHDs, especially for atrial flutter and atrial fibrillation. Patients with moderate and severe complexity congenital heart defects and female ACHDs benefit from upfront referral to specialized CHD centers for CA. Centralization of care for ACHD arrhythmias should thus be advocated.

Catheter mapping and ablation during pregnancy

A substantial number of pregnant women at some point experience cardiac arrhythmia, which is mostly treated by antiarrhythmic medication. In some instances, arrhythmias can be drug-resistant and pose a relevant risk to both mother and unborn child as they can result in hemodynamic compromise. In recent years, invasive electrophysiology procedures have been carried out with ever reducing exposure to ionising radiation, and multiple techniques have been established to achieve ZERO exposure. Of course, these techniques should all be applied when contemplating an invasive mapping and ablation procedure during pregnancy. The role of the cardio-obstetrics team in planning and performing such procedures is paramount. Careful assessment of the pregnant mother and her unborn child is mandatory. Only with good preparation is a complete understanding of both cardiac anatomy and physiology achievable, which is a pre-requisite of a successful ablation outcome. Various aspects of the ablation procedure itself are discussed and evaluated from the perspective of all team members involved, including the obstetrician, the anaesthetist and the electrophysiologist. This review aims to inform the reader about the techniques available and reports on the published outcomes for ablations during pregnancy in the last decade.

New developments in catheter ablation for patients with congenital heart disease

Introduction: There are numerous challenges to catheter ablation in patients with congenital heart disease (CHD), including access to cardiac chambers, distorted anatomies, displaced conduction systems, multiple and/or complex arrhythmia substrates, and excessively thickened walls, or interposed material. Areas covered: Herein, we review recent developments in catheter ablation strategies for patients with CHD that are helpful in addressing these challenges. Expert opinion: Remote magnetic navigation overcomes many challenges associated with vascular obstructions, chamber access, and catheter contact. Patients with CHD may benefit from a range of ablation catheter technologies, including irrigated-tip and contact-force radiofrequency ablation and focal and balloon cryoablation. High-density mapping, along with advances in multipolar catheters and interpolation algorithms, is contributing to new mechanistic insights into complex arrhythmias. Ripple mapping allows the activation wave front to be tracked visually without prior assignment of local activation times or window of interest, and without interpolations of unmapped regions. There is growing interest in measuring conduction velocities to identify arrhythmogenic substrates. Noninvasive mapping with a multielectrode-embedded vest allows prolonged bedside monitoring, which is of particular interest in those with non-sustained or multiple arrhythmias. Further studies are required to assess the role of radiofrequency needle catheters and stereotactic radiotherapy in patients with CHD.

The role of 3D-high definition mapping systems in treating postoperative drug-resistant intra-atrial reentrant tachycardia

We report the case of a patient with recurrent episodes of postoperative intra-atrial reentrant tachycardia occurring after surgical patch closure of a sinus venosus atrial septal defect (SVASD). Arrhythmic episodes, as usually reported in scar-related arrhythmias, were resistant to antiarrhythmic therapy and worsened patient's quality of life. Therefore, we decided to perform an intracardiac electrophysiology study using a 3D-high definition mapping system to identify and treat the precise arrhythmic substrate with radiofrequency ablation. There is a growing evidence that this technique represents a valid therapeutic option in postoperative arrhythmias refractory to medical treatment in patients with repaired congenital heart disease.

Impact of preoperative electrophysiological intervention on occurrence of peri/postoperative supraventricular tachycardia following Fontan surgery

BACKGROUND

Little is known about the effects of preoperative electrophysiological study (EPS) and catheter ablation (CA) in Fontan surgery candidates with supraventricular tachycardia (SVT).

OBJECTIVE

The purpose of this study was to investigate the clinical impact of EPS-guided intervention in Fontan surgery candidates with preceding SVT events.

METHODS

A total of 109 consecutive patients with a history of SVT before Fontan surgery were divided into 3 groups: 44 in whom EPS with CA was attempted (CA group); 21 in whom EPS without CA was attempted (EPS group); and 44 in whom EPS was not performed (N group). The incidence and diagnosis of SVT, acute success rate of CA, and risk factors of peri/postoperative SVT were retrospectively investigated.

RESULTS

The total incidence of SVT within 1 year after Fontan surgery was 34% (n = 37), with 91% of cases occurring within 1 month. Among the 71 SVT incidences diagnosed with EPS, 31 were atrioventricular reentrant tachycardias (AVRTs) involving twin atrioventricular nodes, 12 were atrioventricular nodal reentrant tachycardias, 12 were atrial tachycardias, 7 were orthodromic AVRTs via the accessory pathway, 7 were atrial flutters, and 2 were junctional tachycardias. The acute success rate of CA was 91% (48/53). The rate of peri/postoperative atrioventricular reciprocating SVT was significantly lower in the CA group than in the N or EPS group (11% vs 43% or 43%; P <.05). No/unsuccessful CA significantly increased the risk of peri/postoperative SVT in multivariate analysis (odds ratio 4.43; 95% confidence interval 1.69-11.59).

CONCLUSION

Preoperative CA reduces peri/postoperative SVT occurrence in Fontan surgery candidates at high risk for SVT.

Initial Experience Using the Radiofrequency Needle Visualization on the Electroanatomical Mapping System for Transseptal Puncture

INTRODUCTION

Transseptal puncture (TSP) is a routine access route in patients with left-sided ablation substrates and is performed safely on fluoroscopy (+/- echocardiographic guidance). We report on our experience using a radiofrequency (RF) needle in an unselected group of patients to demonstrate safety and usefulness of direct tip visualization on the 3D electroanatomical mapping (EAM) system with specific emphasis on total radiation exposure.

METHODS AND RESULTS

We retrospectively reviewed 42 consecutive left-sided ablation procedures with TSP performed using an RF needle guided by fluoroscopy and/or EAM visualization by a single operator. The procedures included atrial fibrillation (n = 33), atrial tachycardia (n = 8), and ventricular tachycardia (n = 1) ablations. Fourteen of 41 patients had congenital heart disease, including 9 patients with previous septal closure. Twenty-two patients had at least one previous TSP. All TSPs were performed successfully and without complications. The overall median fluoroscopy time amounted to 3.2 min and median exposure of 199.5 µGy ∗ m2. In a subgroup of patients (n = 27), the RF needle was visualized on the EAM system: median radiation time was 0.88 (interquartile range: 0-3.4) min and median exposure 33.5 [0-324.8] µGy ∗ m2.

CONCLUSIONS

TSP using an RF needle is an effective technique, also in congenital patients with artificial patch material and in normal patients with multiple previous TSPs. Moreover, the RF needle tip visualization on EAM allows a low (or even zero) fluoroscopy approach.

Characterization of the Mechanism and Substrate of Atrial Tachycardia Using Ultra-High-Density Mapping in Adults With Congenital Heart Disease: Impact on Clinical Outcomes

Background

Atrial tachycardia (AT) is common in patients with adult congenital heart disease and is challenging to map and ablate. We used ultra‐high‐density mapping to characterize the AT mechanism and investigate whether substrate characteristics are related to ablation outcomes.

Methods and Results

A total of 50 ATs were mapped with ultra‐high‐density mapping in 23 procedures. Patients were followed up for up to 12 months. Procedures were classified to group A if there was 1 single AT induced (n=12) and group B if there were ≥2 ATs induced (n=11 procedures). AT mechanism per procedure was macro re‐entry (n=10) and localized re‐entry (n=2) in group A and multiple focal (n=6) or multiple macro re‐entry (n=5) in group B. Procedure duration, low voltage area (0.05–0.5 mV), and low voltage area indexed for volume were higher in group B (159 [147–180] versus 412 [352–420] minutes, P<0.001, 22.6 [12.2–29.8] versus 54.2 [51.1–61.6] cm², P=0.014 and 0.17 [0.12–0.21] versus 0.26 [0.23–0.27] cm²/mL, P=0.024 accordingly). Dense scar (<0.05 mV) and atrial volume were similar between groups. Acute success and freedom from arrhythmia recurrence were worse in group B (100% versus 77% P=0.009 and 11.3, CI 9.8–12.7 versus 4.9, CI 2.2–7.6 months, log rank P=0.004). Indexed low voltage area ≥0.24 cm²/mL could predict recurrence with 100% sensitivity and 77% specificity (area under the curve 0.923, P=0.007).

Conclusions

Larger low voltage area but not dense scar is associated with the induction of multiple focal or re‐entry ATs, which are subsequently associated with longer procedure duration and worse acute and midterm clinical outcomes.

Catheter ablation for patients with end-stage complex congenital heart disease or cardiomyopathy considered for transplantation: Trials and tribulations

INTRODUCTION

Arrhythmia contributes significantly to morbidity and mortality of patients with congenital heart disease (CHD) or cardiomyopathy (CMP). It also has the potential to worsen symptoms and is particularly detrimental to patients with advanced heart failure awaiting cardiac transplantation. We report our experience using catheter ablation to treat recurrent arrhythmia in patients with CHD or CMP considered for transplantation.

METHODS

Five consecutive patients (3 female, mean age 47.8 ± 12.8 years) with complex CHD or CMP (tricuspid atresia, mitral atresia, double inlet left ventricle, arrhythmogenic right ventricular cardiomyopathy, left ventricular non-compaction) presented with either atrial (n = 3) or ventricular (n = 2) arrhythmias. All ablations were guided by three-dimensional (3D) electro-anatomical mapping, plus remote magnetic navigation in 3 patients.

RESULTS

Patients underwent a median of 2 ablation procedures for a total number of 26 tachycardias. None of the 5 patients experienced further arrhythmia at a median of 939 days (range 4-1375) from their last ablation. During a median follow up of 31 months (range 1-70), three patients underwent successful transplantation at 1375, 1062 and 321 days following their last ablation. One patient with a Fontan circulation died from hepatic cancer and one from end-stage heart failure despite urgent transplant listing.

CONCLUSIONS

Catheter ablation is feasible in complex cardiac patients considered for heart transplantation and should be offered for rhythm management and patient optimization until a suitable donor is found.

Missing pouches in high-density mapping of atrial tachyarrhythmia in congenital heart diseases

BACKGROUND

The use of high-density electroanatomical mapping in the Chinese population for congenital heart disease (CHD) is not well reported.

METHODS

Retrospective review of consecutive transcatheter ablation of atrial tachyarrhythmia using high-density mapping for CHD patients (at least moderate complexity) in the only tertiary congenital heart center in the territory from January 2017 to January 2019 was conducted. Orion mapping catheter in Rhythmia system (Boston Scientific) was used to create activation and voltage maps. Parameters including mechanism of arrhythmia, acute success, and follow-up data were recorded.

RESULTS

Eight patients were identified (median age 35.5 years) who underwent transcatheter ablation of atrial arrhythmia. More than one reentry circuits of IART were identified in five patients. It took a median of 32.4 minutes with 15,952 (IQR 13,395-18,530) mapping points per map. Cavo-annulus isthmus-dependent mechanism was the predominant reentry mechanism. Acute success with the elimination of all inducible tachycardia was achieved in six patients (75%), and partial success in two patients. There was recurrence of atrial arrhythmia in four patients (50%), in which three patients could be maintained in sinus rhythm with low-dose antiarrhythmic medication. Targeted substrate ablation was performed in six patients with multiple IART circuits. Critical anatomical pouches were identified in three patients, which were missed in the initial mapping using Orion basket mapping catheter.

CONCLUSIONS

High acute success rate of atrial arrhythmia ablation can be achieved using high-density anatomical mapping in CHD. Substrate ablation was required with multiple IART circuits identified. Vigilance should be sought to identify anatomical pouches.

Arrhythmia Mechanisms and Outcomes of Ablation in Pediatric Patients With Congenital Heart Disease

BACKGROUND

In contrast to the adult population with congenital heart disease (CHD), arrhythmia mechanisms and outcomes of ablation in pediatric patients with CHD in recent era have not been studied in detail. Aims of this study were to determine arrhythmia mechanisms and to evaluate procedural and long-term outcomes in pediatric patients with CHD undergoing catheter ablation.

METHODS

Consecutive patients <18 years of age with CHD undergoing catheter ablation over an 11-year period (2007-2018) were included. Procedural outcome included complete or partial success, failure or empirical ablation. Long-term outcome included arrhythmia recurrence and burden according to a 12-point clinical arrhythmia severity score.

RESULTS

The study population consisted of 232 patients (11.7 years [0.01-17.8], 33.5 kg [2.2-130.1]). The most common diagnoses were Ebstein's anomaly (n=44), septal defects (n=39), and single ventricle (n=36). Arrhythmia mechanisms included atrioventricular reentry tachycardia (n=104, 90 patients), atrioventricular nodal reentry tachycardia (n=33, 29 patients), twin atrioventricular nodal tachycardia (n=3, 2 patients), macroreentrant atrial tachycardia (n=59, 56 patients), focal atrial tachycardia (n=33, 25 patients), ventricular ectopy (n=10, 8 patients), and ventricular tachycardia (n=15, 13 patients). Fifty-six arrhythmias (39 patients) were undefined. Outcomes included complete success (n=189, 81%), partial success (n=7, 3%), failure (n=16, 7%), or empirical ablation (n=20, 9%). Over 3.6 years (0.3-10.7) arrhythmia recurred in 49%. Independent of arrhythmia recurrence, arrhythmia scores decreased from 4 (0-10) at baseline to 0.5 (0-8) at 4 years follow-up (P<0.001). In 23/51 repeat procedures (45%), a different arrhythmia substrate was found. Overall adverse event rate was 9.4%, although only 1.6% (n=4) were of major severity and 0.8% (n=2) of moderate severity.

CONCLUSIONS

Pediatric patients with CHD demonstrate a broad spectrum of arrhythmia mechanisms. Despite recurrence and emergence of novel mechanisms after a successful procedure, ablation can be performed safely and successfully resulting in decreased arrhythmia burden.

Advanced mapping strategies for ablation therapy in adults with congenital heart disease

Background

Ultra-high density mapping (HDM) is a promising tool in the treatment of patients with complex arrhythmias. In adults with congenital heart disease (CHD), rhythm disorders are among the most common complications but catheter ablation can be challenging due to heterogenous anatomy and complex arrhythmogenic substrates. Here, we describe our initial experience using HDM in conjunction with novel automated annotation algorithms in patients with moderate to great CHD complexity.

Methods

We studied a series of consecutive adult patients with moderate to great CHD complexity and an indication for catheter ablation due to symptomatic arrhythmia. HDM was conducted using the Rhythmia™ mapping system and a 64-electrode mini-basket catheter for identification of anatomy, voltage, activation pattern and critical areas of arrhythmia for ablation guidance. To investigate novel advanced mapping strategies, postprocedural signal processing using the Lumipoint™ software was applied.

Results

In 19 patients (53±3 years; 53% male), 21 consecutive ablation procedures were conducted. Procedures included ablation of atrial fibrillation (n=7; 33%), atrial tachycardia (n=11; 52%), atrioventricular accessory pathway (n=1; 5%), the atrioventricular node (n=1; 5%) and ventricular arrhythmias (n=4; 19%). A total of 23 supraventricular and 8 ventricular arrhythmias were studied with the generation of 56 complete high density maps (atrial n=43; ventricular n=11, coronary sinus n=2) and an average of 12,043±1,679 mapping points. Multiple arrhythmias were observed in n=7 procedures (33% of procedures; range of arrhythmias detected 2-4). A total range of 1-4 critical areas were defined per procedure and treated within a radiofrequency application time of 16 (interquartile range 12-45) minutes. Postprocedural signal processing using Lumipoint™ allowed rapid annotation of fractionated signals within specific windows of interest. This supported identification of a practical critical isthmus in 20 out of 27 completed atrial and ventricular tachycardia activation maps.

Conclusions

Our findings suggest that HDM in conjunction with novel automated annotation algorithms provides detailed insights into arrhythmia mechanisms and might facilitate tailored catheter ablation in patients with moderate to great CHD complexity.

Efficacy of catheter ablation for atrial fibrillation in patients with congenital heart disease

Aims

Advances in surgical techniques allow an increasing number of children with congenital heart disease (CHD) to reach adulthood. As patients grow older, atrial fibrillation (AF) is evolving into a major clinical concern and can be difficult to manage medically. Primary AF catheter ablation may, therefore, have a role in this setting but few reports have evaluated its efficacy in CHD patients.

Methods and results

We retrospectively reviewed 58 consecutive patients [median age 51, interquartile range (IQR) 44–63 years, 57% male] with AF (45% paroxysmal) who underwent 122 ablation procedures in our tertiary centre in the last decade. The majority had CHD of moderate or severe complexity (57%, Bethesda Class 2 or 3) with a dilated left atrium (LA) (81%) and/or right atrium (86%). At 1-year from the first ablation, 32.8% of patients remained in sinus rhythm. Multiple procedures were required in 35 (60%) patients. Freedom from AF at 1-year after the 2nd and 3rd ablation was 40.9% and 36.5%, respectively. Multivariable predictors of AF recurrence were underlying anatomic complexity [hazard ratio (HR) in Bethesda 3 1.98, P = 0.006], type of AF (HR for persistent 1.87, P = 0.004), and indexed LA dimensions (HR for cm2/m2 1.06, P = 0.03).

Conclusion

While ablation may be a valid option for the treatment of AF in CHD patients, multiple procedures are likely to be required. Early referral and careful patient selection are essential to optimize the results of AF ablation, achieving a low rate of recurrence. Further studies are needed to validate our prognostic model and guide clinical practice.

Catheter Ablation for Atrial Tachycardia in Adults With Congenital Heart Disease: Electrophysiological Predictors of Acute Procedural Success and Post-Procedure Atrial Tachycardia Recurrence

OBJECTIVES

This study sought to determine the electrophysiological predictors of acute procedural success and of post-ablation recurrence of atrial tachyarrhythmias (ATs) in our adult congenital heart disease (ACHD) population undergoing catheter ablation for treatment of AT.

BACKGROUND

Catheter ablation is frequently performed to treat persistent AT in ACHD. The predictors of post-ablation AT recurrence have not been well studied in the ACHD population.

METHODS

The authors performed a retrospective study of all catheter ablations for treatment of AT performed in ACHD patients between December 1, 2005, and July 20, 2017, at Columbia University Medical Center. Pre-specified clinical and procedural data of interest and the time from ablation to recurrence were determined by chart and procedure report review.

RESULTS

A total of 140 patients (mean age: 45 years) underwent catheter ablation for 182 AT. Of the AT, 179 (93%) were intra-atrial macro-re-entrant tachycardia, and 12 (7%) had a focal origin. The presence of a single mechanism was a predictor of acute procedural success that could be achieved in 89% of the patients. At a median of 49.9 months, 62 patients (44%) had recurrent AT. Time to recurrence was significantly shorter (12.5 months) for recurrent AT in 13 of the 20 patients with previous Fontan procedure. By multivariable analysis, acute procedural success was a positive predictor and prior surgical maze procedure was a negative predictor of AT-free survival. Of the 62 patients with recurrent AT, 42 (68%) had a second catheter ablation procedure, and in 22 of these, the AT mechanism was different than previously observed.

CONCLUSIONS

Catheter ablation for AT in ACHD patients is an effective method of arrhythmia control. More than 1 AT mechanism per patient is common. Acute procedural success is a predictor of freedom from AT recurrence. The majority of patients achieve multiple arrhythmia-free years.

An initial experience of high-density mapping-guided ablation in a cohort of patients with adult congenital heart disease

AIMS

In the management of both ventricular and supraventricular tachycardia in patients with congenital heart disease (CHD) catheter ablation has now been recognized as one of the mainstays.

METHODS AND RESULTS

We review our initial experience of using the Rhythmia mapping system in a cohort of 12 adult CHD patients presenting with multiple arrhythmia substrates. A total of 78 arrhythmia maps were attempted in a total of 15 procedures, but possible due to the dilatation of the target chamber only 44% of maps were able to reconstruct the entire arrhythmia. All patients underwent pre-procedure 3D imaging (either cardiac magnetic resonance or computed tomography), but image integration was suboptimal. A median of two maps per patient were finally analysed and acquisition took in median 22 min with a median number of 12 574 (8230-18 167) mapping points. Procedural data with a total duration amounting to in median 285 (194-403) min, with a median total fluoroscopy exposure of 7.5 (5.2-10.7) min. After a median of 1.5 procedures [median of 12 (8-16 months)], nine patients remained in stable sinus rhythm or atrial paced rhythm, while three patients had further sustained recurrences. One of these passed away in end-staged heart failure.

CONCLUSION

This initial experience of using high-density mapping for arrhythmia management in patients with CHD allowed rapid acquisition of multiple maps with high accuracy to identify surgical scars and fibrosis, however, it was limited by large atrial volumes and a high percentage of incomplete maps resulting in modest clinical success.

Mechanisms of Intra-Atrial Re-Entrant Tachycardias in Congenital Heart Disease: Types and Predictors

Intra-atrial re-entrant tachycardia (IART) is a severe complication in patients with congenital heart disease (CHD). Cavotricuspid isthmus (CTI)-related IART is the most frequent mechanism. However, due to fibrosis and surgical scars, non-CTI-related IART is frequent. The main objective of this study was to describe the types of IART, circuit locations, and to analyze predictors of CTI versus non-CTI-related IART. This is an observational study that includes all consecutive patients with CHD who underwent a first IART ablation in a single referral tertiary hospital from January 2009 to December 2015 (94 patients; 39.4% women; age: 36.55 ± 14.9 years, 40.4% with highly complex cardiac disease). During the study, 114 IARTs were ablated (1.21 ± 0.41 IARTs per patient). CTI-related IART was the only arrhythmia in 51% (n = 48) of patients; non-CTI-related IART was the only mechanism in 27.7% (n = 26), and 21.3% of patients (n = 20) presented the two types of IART. Severe dilation of the systemic ventricle, absence of severe dilation of the venous atrium, highly complex cardiac defects, and nontypical electrocardiography (ECG) were related to non-CTI-related IART in univariate analysis. In multivariate analysis, nontypical ECG (odds ratio 3.64; 1.01 to 4.9; p = 0.049) and grade III CHD complexity (odds ratio 9.43; 1.44 to 11.7; p = 0.001) were predictors of non-CTI-related IART. In conclusion, in our population with a high proportion of complex CHD, CTI-related IART was the most frequent mechanism, although non-CTI-related IART was present in 49% (alone or with concomitant CTI-related IART). High-grade CHD complexity and nontypical ECG were strongly related to non-CTI IART.

Electrophysiology and structural interventions in adults with congenital heart disease: Comparison of combined versus separate procedures

BACKGROUND

Electrophysiologic (EP) and structural interventions in adult congenital heart disease (ACHD) are typically completed during separate hospital encounters. With planning/coordination, these cases can be combined.

OBJECTIVES

We hypothesized that this integrated approach would yield patient and health system benefits.

METHODS

Consecutive ACHD patients undergoing combined interventions were matched to controls with identical but separate procedures. Primary endpoints of total hospital length of stay and cost were compared.

RESULTS

Sixty-six combined cases and 120 controls were identified (45% male, mean age 36.2 ± 14.2 years). The most common diagnoses were Fontan (27%), tetralogy of Fallot (23%), and transposition complexes (20%). The most common EP procedure was catheter ablation (n = 30) followed by electrophysiologic study (n = 13); the most common structural intervention was transcatheter valve replacement (n = 16) followed by angioplasty/stenting (n = 14). Compared to controls, cases showed shorter anesthesia duration (323 [IQR 238-405] vs. 355 minutes [270-498], P = 0.06), smaller contrast dose (130 [50-189] vs. 177 mL [94-228], P = 0.045), fewer venipunctures (4 [3-4] vs. 6 [5-7], P < 0.001), and fewer work days missed (2 [2-5] vs. 4 [4-6], P < 0.001). There was shorter hospital stay (30 [19-35] vs. 38 hours [26-50], P = 0.023) and a 37% reduction in hospital charges ($117,894 vs. $187,648; P = 0.039) and 27% reduction in payments ($65,757 vs. $88,859; P = 0.016), persisting after adjustment for group differences. There were no significant differences in number of complications or efficacy.

CONCLUSIONS

There appear to be advantages to combining ACHD interventional procedures that include reductions in hospital length of stay and cost, without detectable difference in procedural outcome.

Predictors of Acute Failure Ablation of Intra-atrial Re-entrant Tachycardia in Patients With Congenital Heart Disease: Cardiac Disease, Atypical Flutter, and Previous Atrial Fibrillation

BACKGROUND

Intra-atrial re-entrant tachycardia (IART) in patients with congenital heart disease (CHD) increases morbidity and mortality. Radiofrequency catheter ablation has evolved as the first-line treatment. The aim of this study was to analyze the acute success and to identify predictors of failed IART radiofrequency catheter ablation in CHD.

METHODS AND RESULTS

The observational study included all consecutive patients with CHD who underwent a first ablation procedure for IART at a single center from January 2009 to December 2015 (94 patients, 39.4% female, age: 36.55±14.9 years). In the first procedure, 114 IART were ablated (acute success: 74.6%; 1.21±0.41 IART per patient) with an acute success of 74.5%. Cavotricuspid isthmus-related IART was the only arrhythmia in 51%; non-cavotricuspid isthmus-related IART was the only mechanism in 27.7% and 21.3% of the patients had both types of IART. Predictors of acute radiofrequency catheter ablation failure were as follows: nonrelated cavotricuspid isthmus IART (odds ratio 7.3; confidence interval [CI], 1.9-17.9; P=0.04), previous atrial fibrillation (odds ratio 6.1; CI, 1.3-18.4; P=0.02), transposition of great arteries (odds ratio, 4.9; CI, 1.4-17.2; P=0.01) and systemic ventricle dilation (odds ratio 4.8; CI, 1.1-21.7; P=0.04) with an area under the receiver operating characteristic curve of 0.83±0.056 (CI, 0.74-0.93, P=0.001). After a mean follow-up longer than 3.5 years, 78.3% of the patients were in sinus rhythm (33.1% of the patients required more than 1 radiofrequency catheter ablation procedure).

CONCLUSIONS

Although ablation in CHD is a challenging procedure, acute success of 75% can be achieved in moderate-highly complex CHD patients in a referral center. Predictors of failed ablation are IART different from cavotricuspid isthmus, previous atrial fibrillation, and markers of complex CHD (transposition of great arteries, systemic ventricle dilation).

Radiofrequency Catheter Ablation of Atrial Tachycardias in Congenital Heart Disease

Background

Radiofrequency catheter ablation has become the treatment strategy of choice for atrial tachyarrhythmias in patients with congenital heart disease (CHD). We analyzed results of radiofrequency catheter ablation in a large cohort of patients with CHD with special reference to complexity of underlying anatomy.

Methods and Results

One hundred and forty-four patients with CHD and atrial tachyarrhythmias undergoing radiofrequency catheter ablation were classified according to complexity of underlying CHD: simple CHD, n=18 (12%); moderate CHD, n=53 (37%); and complex CHD, n=73 (51%). Overall acute success was achieved in 81% of the patients. Acute success was lower for tachycardias involving the left atrium compared with right atrial tachycardias. Complexity of CHD was associated with longer procedure duration. Tachycardia recurrence was observed in 54% of the patients after a total follow-up of 7.4 years. 75% of all recurrences occurred within the first year. Recurrence of tachycardia was more likely in patients with complex surgical atrial anatomy (ie, Fontan palliation or atrial switch procedure). Major complications occurred in 4 patients and were related to vascular access.

Conclusions

Acute procedural success of atrial tachycardia ablation in congenital heart patients was not influenced by complexity of CHD. Long-term outcome with regard to tachycardia recurrence was worse in patients with complex surgical atrial anatomy.

Atrioventricular Nodal Reentrant Tachycardia in Patients With Congenital Heart Disease

Background—

The relationship of atrioventricular nodal reentrant tachycardia to congenital heart disease (CHD) and the outcome of catheter ablation in this population have not been studied adequately.

Methods and Results—

A multicenter retrospective study was performed on patients with CHD who had atrioventricular nodal reentrant tachycardia and were treated with catheter ablation. There were 109 patients (61 women), aged 22.1±13.4 years. The majority, 86 of 109 (79%), had CHD resulting in right heart pressure or volume overload. Patients were divided into 2 groups: group A (n=51) with complex CHD and group B (n=58) with simple CHD. There were no significant differences between groups in patients’ growth parameters, use of 3-dimensional imaging, and type of ablation (radiofrequency versus cryoablation). Procedure times (251±117 versus 174±94 minutes; P =0.0006) and fluoroscopy times (median 20.8 versus 16.6 minutes; P =0.037) were longer in group A versus group B. There were significant differences between groups in the acute success of ablation (82% versus 97%; P =0.04), risk of atrioventricular block (14 versus 0%; P =0.004), and need for chronic pacing (10% versus 0%; P =0.008). There was no permanent atrioventricular block in patients who underwent cryoablation. After 3.2±2.7 years of follow-up, long-term success was 86% in group A and 100% in group B ( P =0.004).

Conclusions—

Atrioventricular nodal reentrant tachycardia can complicate the course of patients with CHD. This study demonstrates that the outcome of catheter ablation is favorable in patients with simple CHD. Patients with complex CHD have increased risk of procedural failure and atrioventricular block.

Arrhythmia Surgery for Adults with Congenital Heart Disease

Patients with repaired or unrepaired congenital heart anomalies are at increased risk for arrhythmia development throughout their lives, often paralleling the need for reoperations for hemodynamic residua. The ability to incorporate arrhythmia surgery into reoperations can result in improvement in functional class and decreased need for antiarrhythmic medications. Every reoperation for congenital heart disease can be viewed as an opportunity to assess the electrical and arrhythmia substrates and to intervene to improve the arrhythmias and the hemodynamic condition of the patient. The authors review and summarize the operative techniques for arrhythmia surgery that are based on the arrhythmia mechanisms.

Supraventricular Arrhythmias in Patients with Adult Congenital Heart Disease

An increasing number of patients with congenital heart disease survive to adulthood; such prolonged survival is related to a rapid evolution of successful surgical repairs and modern diagnostic techniques. Despite these improvements, corrective atrial incisions performed at surgery still lead to subsequent myocardial scarring harbouring a potential substrate for macro-reentrant atrial tachycardia. Macroreentrant atrial tachycardias are the most common (75 %) type of supraventricular tachycardia (SVT) in patients with adult congenital heart disease (ACHD). Patients with ACHD, atrial tachycardias and impaired ventricular function - important risk factors for sudden cardiac death (SCD) - have a 2-9 % SCD risk per decade. Moreover, ACHD imposes certain considerations when choosing antiarrhythmic drugs from a safety aspect and also when considering catheter ablation procedures related to the inherent cardiac anatomical barriers and required expertise. Expert recommendations for physicians managing these patients are therefore mandatory. This review summarises current evidence-based developments in the field, focusing on advances in and general recommendations for the management of ACHD, including the recently published recommendations on management of SVT by the European Heart Rhythm Association.