Update on interventional electrophysiology in congenital heart disease: evolving solutions for complex hearts

Mid-term outcomes after catheter ablation in patients with congenital heart disease

INTRODUCTION

Cardiac arrhythmias are a major concern in patients with CHD. The purpose of this study was to evaluate the long-term outcomes in patients with CHD submitted to catheter ablation.

MATERIALS AND METHODS

Observational retrospective study of patients with CHD referred for catheter ablation from January 2016 to December 2021 in a tertiary referral centre. Acute procedural endpoints and long-term outcomes were assessed.

RESULTS

A total of 44 ablation procedures were performed in 36 CHD patients (55% male, mean age 43 ±3 years). Fifty-four arrhythmias were ablated: 23 cavotricuspid isthmus atrial flutters, 10 atrial re-entrant tachycardias, eight focal atrial tachycardias, eight atrial fibrillations, three atrioventricular re-entrant tachycardias, and two ventricular tachycardias. During a median follow-up time of 37 months (interquartile range 12-51), freedom from arrhythmia recurrence was achieved in 93%, with 1.2 procedures per patient (18% with anti-arrhythmic drugs). There were no adverse events related to catheter ablation. No predictors of recurrence were identified.

CONCLUSION

In patients with CHD, catheter ablation presents a high mid-term efficacy while maintaining a safe profile.

A Twenty-Year Follow-Up of Adults with Ebstein Anomaly with Special Focus on Supraventricular Arrhythmias, Supraventricular Arrhythmias and Effectiveness of Catheter Ablation in 20-Year Follow-Up of Adults with Ebstein Anomaly

Background: Ebstein anomaly (EA) is a rare congenital heart disease characterized by the apical displacement of the tricuspid leaflets, creating an enlarged functional right atrium. Supraventricular arrhythmias (SVA) are common, and catheter ablation remains challenging. SVA is considered a risk factor for sudden cardiac death in this population. Still, there are very few real-life data on the impact of SVA treated invasively or conservatively on a patient's prognosis. We aimed to analyze the incidence of SVA in adults with EA, evaluate the effectiveness of catheter ablation, and analyze the impact of SVA and catheter ablation on survival in this population. Methods and results: 71 pts (median age 53 years; range 24-84 years) with EA were evaluated retrospectively from 1988 to 2020. Forty patients (56.3%) had SVA, and eighteen of them (45.0%) required at least one catheter ablation (35 procedures in total). Indications for ablation were mostly intra-atrial reentrant tachycardia (IART) and atrioventricular reentrant tachycardia (AVRT) (14 pts [77.8% and 9 pts [50.0%], respectively. IART and AVRT coexisted in nine pts. One patient suffered from persistent atrial fibrillation. Procedural effectiveness was reported in 28 (80%) cases; over a longer follow-up (mean 12.6 ± 5.4 years), only eight (44.4%) patients were completely free from SVA after the first ablation. In total, 10 patients (14%) died due to cardiovascular events. There was no difference in survival between patients with or without SVA (p = 0.9) and between ablated and non-ablated EA individuals (p = 0.89). Conclusions: Supraventricular arrhythmia is frequent in adults with Ebstein anomaly. Patients often require more than one catheter ablation but eventually become free from arrhythmias. The imaging parameters assessed by echocardiography or cardiac magnetic resonance do not seem to be associated with ablation outcomes. The impact of supraventricular arrhythmia itself or treatment with radiofrequency ablation is questionable and should be thoroughly investigated in this population.

Atrial Fibrillation Ablation in Congenital Heart Disease: Therapeutic Challenges and Future Perspectives

The increasing prevalence of atrial fibrillation (AF) in adults with congenital heart disease raises significant questions regarding its management. The unique underlying anatomic and physiological background further adds to the difficulty in eliminating the AF burden in these patients. Herein, we provide an overview of the current knowledge on the pathophysiology and risk factors for AF in adult congenital heart disease, with a special focus on the existing challenges in AF ablation. Emerging imaging modalities and ablation techniques might have a role to play. Evidence regarding the safety and efficacy of AF ablation in adult congenital heart disease is summarized, especially for patients with an atrial septal defect, Ebstein anomaly of the tricuspid valve, tetralogy of Fallot, and Fontan circulation. Finally, any remaining gaps in knowledge and potential areas of future research are highlighted.

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.

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.

Atrial Fibrillation in Congenital Heart Disease

The increasing prevalence of AF in a growing population of adults with congenital heart disease (CHD) poses new challenges to clinicians involved in the management of these patients. Distinctive underlying anatomies, unique physiological aspects, a high diversity of corrective surgeries and associated comorbidities can complicate clinical decision-making. In this review, the authors provide an overview of the current knowledge on epidemiology and pathophysiology, with a special focus on the differences to the non-CHD population and the clinical impact of AF in adults with CHD. Acute and long-term management strategies are summarised, including the use of antiarrhythmic drugs, catheter or surgical ablation and prophylaxis of thromboembolism. Finally, gaps of knowledge and potential areas of future research are highlighted.

Long-term results of atrial maze surgery in patients with congenital heart disease

AIMS

Recurrent atrial tachycardia is common after repair of many types of congenital heart disease, and surgical ablation with a maze procedure represents a potential treatment strategy. The objective of this study is to report a single-centre 19 years' experience with maze surgery in congenital heart patients.

METHODS AND RESULTS

Patients undergoing maze procedure concomitantly with cardiac surgical procedures were retrospectively analysed. The maze procedure was classified as therapeutic if the patient demonstrated preoperative atrial arrhythmias, or as prophylactic if done because the patient was considered high risk for post-operative arrhythmias. Acute outcomes and longer-term freedom from atrial arrhythmias were analysed. Maze surgery was performed in 166 patients: 137 in the therapeutic group, and 29 in the prophylactic group. The most common congenital heart lesion was single ventricle for the therapeutic group (27%) and Ebstein's anomaly for the prophylactic group (76%). Surgery consisted of a right atrial maze in 63%, left atrial maze in 4%, and bilateral maze in 33%. There were no direct complications or mortality related to the maze procedure itself. For the therapeutic group, freedom from arrhythmias was 82% and 67% at 1 and 5 years post-maze. Younger age at the time of surgery correlated with a lower long-term recurrence risk.

CONCLUSION

Maze procedure at the time of an elective anatomic surgery is reasonably effective to prevent and treat atrial arrhythmias in patients with congenital heart disease at short- and mid-term, with low morbidity and mortality.

Examination of pathologic features of the right atrioventricular groove in hearts with Ebstein anomaly and correlation with arrhythmias

BACKGROUND

Catheter ablation of accessory pathways (APs) in patients with Ebstein anomaly (EA) has a higher recurrence rate than in subjects with normal hearts. Anatomic features could account for suboptimal ablation outcomes.

OBJECTIVE

The purpose of this study was to examine the right atrioventricular (AV) groove in autopsy hearts with EA, correlate with clinical data, and identify features relevant for catheter ablation.

METHODS

Thirty-three specimens with EA from our Cardiac Registry were examined. The right AV groove was inspected for gross anatomic features. Limited microscopy was performed on selected specimens. Premortem clinical data were correlated with anatomic findings.

RESULTS

A prominent ridge along the right AV groove was seen in 15 of 33 specimens (45%). Ten specimens had a clinical history of AP (AP+). The extent of ventricular atrialization did not differ between AP+ and AP- groups (64 ± 63 mm/m² vs 76 ± 42 mm/m²; P = .61), nor did the presence of visible macroscopic AV tissue connections (45% vs 51%; P = .68). The single item that differed was the presence of an AV groove ridge itself, which was significantly more common in the AP+ group (70% vs 21%; P = .03). Microscopy of ridge tissue revealed a muscular bundle in 1 AP+ specimen penetrating deep into the fibrous AV annulus that was suggestive of an AP, although complete muscular continuity was not verified in the limited sections available for examination.

CONCLUSION

A prominent ridge along the inferior right AV groove is a common feature in EA and correlates with clinical history of AP. It presents a potential obstacle to catheter ablation and may contribute to recurrence rate.

High density mapping and catheter ablation of atrial tachycardias in adults with congenital heart disease

AIMS

We used a new grid-style multi-electrode mapping catheter (Advisor™ HD Grid, Abbott) and investigated its use for high density mapping of atrial tachycardias in adult patients with congenital heart disease.

PATIENTS AND METHODS

All patients with congenital heart disease who had mapping of atrial tachycardias using the new grid-style catheter between March 2018 and April 2019 were included.

RESULTS

A total of 24 adult patients had high density mapping of atrial tachycardias using the grid-style multi-electrode catheter. Mean procedure duration was 207 ± 72 min., mean fluoroscopy time was 7.1 ± 7.9 min. In patients with right atrial substrates, fluoroscopy time was shorter compared to biatrial or left atrial substrates (0.9 ± 2.2 min for right atrial substrates, n = 19 vs. 6.3 ± 8.3 min for left atrial substrates, n = 2 and 7.5 ± 4.3 min for biatrial substrates, n = 3, p = 0.01). A mean number of 14.814 ± 10.140 endocardial points were collected and 2.319 ± 1244 points were finally used to characterize the tachycardia. Procedural success was achieved in 21/24 (88%) subjects and partial success in 2/24 (8%) patients. Recurrence rate was low (12.5%). In one patient, radiofrequency ablation within the cavotricuspid isthmus resulted in occlusion of a branch of the right coronary artery. No complications related to the use of the mapping catheter itself occurred.

CONCLUSION

High density mapping of AT using the grid-style catheter showed promising results with respect to procedural and midterm outcome and fluoroscopy time. Using the grid-style catheter might offer advantages compared to other multi-electrode catheters used for high density mapping of AT in patients with CHD.

Pulmonary vein isolation in a patient with congenital pulmonary atresia: a case report

Background 

Tetralogy of Fallot is a congenital heart defect characterized by pulmonary valve stenosis, ventricular septal defect (VSD), overriding aorta, and right ventricular hypertrophy. In its’ extreme form, the pulmonary valve orifice does not develop during organogenesis, resulting in pulmonary atresia. We report a case of catheter ablation of symptomatic atrial fibrillation (AF) in a 37-year-old patient with congenital pulmonary atresia.

Case summary 

The young man described paroxysmal tachycardia correlating to AF episodes in the previously implanted event recorder. Computed tomography scan described the complex anatomy with congenital pulmonary atresia, VSD, and major aortopulmonary collateral arteries. Electroanatomical mapping revealed typical pulmonary vein electrograms in a hypotrophic left atrium. Modified pulmonary vein isolation was successfully performed and non-excitability of the ablation line was reached. The patient recovered uneventfully and event recorder interrogation showed no AF recurrence after 3 months.

Discussion 

Incidence of pulmonary atresia is low. Untreated survival rate is 50% after 1 year and 8% after 10 years. Tachycardia is a major cause of increased morbidity and mortality in patients with cyanotic congenital heart defects and pulmonary vein foci are described as driver for AF. Considerations preceding catheter ablation included pathophysiological mechanism, complex anatomy, atypical left atrium access, and reduced pulmonary perfusion resulting in a hypotrophic left atrium. Pulmonary veins showed typical electrograms, and isolation of pulmonary veins was feasible without adverse events.

Current outcomes and treatment of tetralogy of Fallot

Tetralogy of Fallot (ToF) is the most common type of cyanotic congenital heart disease. Since the first surgical repair in 1954, treatment has continuously improved. The treatment strategies currently used in the treatment of ToF result in excellent long-term survival (30 year survival ranges from 68.5% to 90.5%). However, residual problems such as right ventricular outflow tract obstruction, pulmonary regurgitation, and (ventricular) arrhythmia are common and often require re-interventions. Right ventricular dysfunction can be seen following longstanding pulmonary regurgitation and/or stenosis. Performing pulmonary valve replacement or relief of pulmonary stenosis before irreversible right ventricular dysfunction occurs is important, but determining the optimal timing of pulmonary valve replacement is challenging for several reasons. The biological mechanisms underlying dysfunction of the right ventricle as seen in longstanding pulmonary regurgitation are poorly understood. Different methods of assessing the right ventricle are used to predict impending dysfunction. The atrioventricular, ventriculo-arterial and interventricular interactions of the right ventricle play an important role in right ventricle performance, but are not fully elucidated. In this review we present a brief overview of the history of ToF, describe the treatment strategies currently used, and outline the long-term survival, residual lesions, and re-interventions following repair. We discuss important remaining challenges and present the current state of the art regarding these challenges.

Arrhythmias in Adults With Congenital Heart Disease: What the Practicing Cardiologist Needs to Know

The expanding population of adults with congenital heart disease (CHD) combined with the pervasiveness of arrhythmias has resulted in the rapid growth of a dedicated sector of cardiology at the intersection between 2 subspecialties: electrophysiology and adult CHD. Herein, practical considerations are offered regarding urgent referral for catheter ablation of atrial arrhythmias, anticoagulation, and primary prevention implantable cardioverter-defibrillators (ICDs). Patients with Ebstein anomaly and ventricular pre-excitation should be referred promptly due to the high prevalence of multiple accessory pathways and increased incidence of atrial tachyarrhythmias, which may be poorly tolerated. In patients with transposition of the great arteries and atrial switch surgery, atrial arrhythmias should be managed without delay because they could provoke ventricular arrhythmias and sudden death. Other settings in which atrial arrhythmias can be poorly tolerated include single ventricle physiology and Eisenmenger syndrome. Long-term anticoagulation is generally indicated in patients with sustained intra-atrial reentrant tachycardia or atrial fibrillation and a mechanical valve, moderate or severe systemic atrioventricular valve stenosis, traditional risk factors for stroke, and/or moderate or complex CHD. The only class I indication for a primary prevention ICD is a systemic left ventricular ejection fraction ≤ 35%, with biventricular physiology, and New York Heart Association class II or III symptoms. ICD therapy is reasonable in selected adults with tetralogy of Fallot and multiple risk factors for sudden death identified by observational studies. Indications for ICDs in patients with systemic right ventricles and univentricular hearts are less well established, underscoring the need for future research to inform risk stratification.

Feasibility and safety of cryoballoon ablation for the treatment of atrial fibrillation in patients with congenital heart disease

BACKGROUND

The prevalence of atrial fibrillation (AF) is on the rise in the aging population with congenital heart disease (CHD). A few case series have described the feasibility and early outcomes associated with radiofrequency catheter ablation of AF centered on electrically isolating pulmonary veins (PVs) in patients with CHD. In contrast, cryoballoon ablation has not previously been studied in this patient population despite its theoretical advantages, which include a favorable safety profile and shorter procedural time.

AIM

To assess the safety and feasibility of cryoballoon ablation for AF in an initial cohort of patients with CHD.

METHODS

The study population consisted of consecutive patients with CHD who underwent cryoballoon ablation for AF at the Montreal Heart Institute between December 2012 and June 2017. Procedural complications, acute success, and 1-year freedom from recurrent AF after a single procedure with or without antiarrhythmic drugs were assessed. Procedures were performed under conscious sedation. Left atrial access was obtained via a single transseptal puncture or through an existing atrial septal defect (ASD). Cryoballoon occlusion was assessed by distal injection of 50% diluted contrast into the PV. At least one 240-s cryothermal application was performed when complete PV occlusion was obtained. Following ablation, patients were routinely followed at outpatient visits at 1, 3, 6, and 12 mo, and annually thereafter.

RESULTS

Ten patients with a median age of 57.9 (interquartile range 48.2-61.7 years) and 60% female, met the inclusion criteria and were followed for 2.8 (interquartile range 1.4-4.5) years. Two patients had moderately complex CHD (sinus venosus ASD with partial anomalous pulmonary venous return; aortic coarctation with a persistent left superior vena cava), with the remainder having simple defects. AF was paroxysmal in 8 (80.0%) and persistent in 2 (20.0%) patients. The PV anatomy was normal in 6 (60.0%) patients. Four had left common PV (n = 3) and/or 3 right PV (n = 2). Electrical pulmonary vein isolation (PVI) was acutely successful in all patients. One patient had transient phrenic nerve palsy that recovered during the intervention. No major complications occurred. One year after a single ablation procedure, 6 (60%) patients remained AF-free. One patient with recurrent AF had recovered PV conduction and underwent a second PVI procedure. A second patient underwent ablation of an extra-pulmonary vein trigger for AF.

CONCLUSION

Cryoballoon ablation for AF is feasible and safe in patients with simple and moderate forms of CHD, with an excellent acute success rate and modest 1-year freedom from recurrent AF.

Recommendations for the use of electrophysiological study: Update 2018

The field of cardiac electrophysiology has greatly developed during the past decades. Consequently, the use of electrophysiological studies (EPSs) in clinical practice has also significantly augmented, with a progressively increasing number of certified electrophysiology centers and specialists. Since Zipes et al published the Guidelines for Clinical Intracardiac Electrophysiology and Catheter Ablation Procedures in 1995, no official document summarizing current EPS indications has been published. The current paper focuses on summarizing all relevant data of the role of EPS in patients with different types of cardiac pathologies and provides up-to-date recommendations on this topic. For this purpose, the PubMed database was screened for relevant articles in English up to December 2018 and ESC and ACC/AHA Clinical Practice Guidelines, and EHRA/HRS/APHRS position statements related to the current topic were analyzed. Current recommendations for the use of EPS in clinical practice are discussed and presented in 17 distinct cardiac pathologies. A short rationale, evidence, and indications are provided for each cardiac disease/group of diseases. In conclusion, because of its capability to establish a diagnosis in patients with a variety of cardiac pathologies, the EPS remains a useful tool in the evaluation of patients with cardiac arrhythmias and conduction disorders and is capable of establishing indications for cardiac device implantation and guide catheter ablation procedures.

Radiofrequency Ablation of Atrial Fibrillation in Patients with Ebstein's Anomaly: A Two-Case Report

Ebstein's anomaly (EA) is a rare congenital heart disease characterized by “atrialization” of the right ventricle, due to apical displacement of the tricuspid leaflets into the right ventricle. Patients with EA may develop all kinds of supraventricular arrhythmias requiring radiofrequency ablation. Atrial fibrillation (Afib) is a common arrhythmia in EA patients, and results in debilitating symptoms that often require surgical treatment. This is a follow-up report of 2 patients with EA undergoing radiofrequency ablation for Afib. The first patient underwent pulmonary vein isolation (PVI) and the ablation of a concomitant atrioventricular nodal reentrant tachycardia. The second patient was also treated with a PVI and a redo PVI 8 months later. Both patients remain in sinus rhythm 8 months on. Radiofrequency ablation is the therapy of choice for patients with pharmacological refractory Afib, but it is not common in patients with EA.

Dynamic updating atlas for heart segmentation with a nonlinear field-based model

BACKGROUND

Segmentation of cardiac computed tomography (CT) images is an effective method for assessing the dynamic function of the heart and lungs. In the atlas-based heart segmentation approach, the quality of segmentation usually relies upon atlas images, and the selection of those reference images is a key step. The optimal goal in this selection process is to have the reference images as close to the target image as possible.

METHODS

This study proposes an atlas dynamic update algorithm using a scheme of nonlinear deformation field. The proposed method is based on the features among double-source CT (DSCT) slices. The extraction of these features will form a base to construct an average model and the created reference atlas image is updated during the registration process. A nonlinear field-based model was used to effectively implement a 4D cardiac segmentation.

RESULTS

The proposed segmentation framework was validated with 14 4D cardiac CT sequences. The algorithm achieved an acceptable accuracy (1.0-2.8 mm).

CONCLUSION

Our proposed method that combines a nonlinear field-based model and dynamic updating atlas strategies can provide an effective and accurate way for whole heart segmentation. The success of the proposed method largely relies on the effective use of the prior knowledge of the atlas and the similarity explored among the to-be-segmented DSCT sequences.

Supraventricular Tachycardia in Adult Congenital Heart Disease: Mechanisms, Diagnosis, and Clinical Aspects

Supraventricular arrhythmias represent a major source of morbidity in adults with congenital heart disease (ACHD). Anatomic variants and post-operative changes contribute to a unique electrophysiologic milieu ripe for the development of supraventricular tachycardia. Intra-atrial reentrant tachycardia is the most prevalent mechanism. Atrioventricular reciprocating tachycardia is common in lesions associated with accessory pathways. Abnormal anatomy complicates the management of atrioventricular nodal reentrant tachycardia. Tachycardia mediated by twin atrioventricular nodes is rare. Focal tachycardias are considerations in the ACHD population. Each of these tachycardia mechanisms is reviewed, focusing on the inherent diagnostic and therapeutic challenges.

Consensus Document of the Italian Association of Hospital Cardiologists (ANMCO), Italian Society of Pediatric Cardiology (SICP), and Italian Society of Gynaecologists and Obstetrics (SIGO): pregnancy and congenital heart diseases

The success of cardiac surgery over the past 50 years has increased numbers and median age of survivors with congenital heart disease (CHD). Adults now represent two-thirds of patients with CHD; in the USA alone the number is estimated to exceed 1 million. In this population, many affected women reach reproductive age and wish to have children. While in many CHD patients pregnancy can be accomplished successfully, some special situations with complex anatomy, iatrogenic or residual pathology are associated with an increased risk of severe maternal and fetal complications. Pre-conception counselling allows women to come to truly informed choices. Risk stratification tools can also help high-risk women to eventually renounce to pregnancy and to adopt safe contraception options. Once pregnant, women identified as intermediate or high risk should receive multidisciplinary care involving a cardiologist, an obstetrician and an anesthesiologist with specific expertise in managing this peculiar medical challenge. This document is intended to provide cardiologists working in hospitals where an Obstetrics and Gynecology Department is available with a streamlined and practical tool, useful for them to select the best management strategies to deal with a woman affected by CHD who desires to plan pregnancy or is already pregnant.

Preoperative right ventricle voltage mapping in Ebstein's anomaly: can we make the late arrhythmogenic mortality following the cone procedure zero?

A young woman with Epstein's anomaly had a large endocardial scar in the atrialised ventricular myocardium. In patients with significant preoperative ventricular scarring, more information is needed to help appropriately manage the risk of ventricular arrhythmias and sudden death.

Ablation of Atrial Fibrillation in Patients with Congenital Heart Disease

With improved surgical techniques and medical management for patients with congenital heart diseases, more patients are living longer and well into adulthood. This improved survival comes with a price of increased morbidity, mainly secondary to increased risk of tachyarrhythmias. One of the major arrhythmias commonly encountered in this subset of cardiac patients is AF. Similar to the general population, the risk of AF increases with advancing age, and is mainly secondary to the abnormal anatomy, abnormal pressure and volume parameters in the hearts of these patients and to the increased scarring and inflammation seen in the left atrium following multiple surgical procedures. Catheter ablation for AF has been shown to be a very effective treatment modality in patients with refractory AF. However, data and guidelines regarding catheter ablation in patients with congenital heart disease are not well established. This review will shed light on the procedural techniques, success rates and complications of AF catheter ablation in patients with different types of CHD, including atrial septal defects, tetralogy of Fallot, persistent left superior vena cava, heterotaxy syndrome and atrial isomerism, and Ebstein anomaly.

Leadless pacemaker implantation in a patient with complex congenital heart disease and limited vascular access

Management of rhythm related issues might be particularly challenging in patients with congenital heart disease due to complex anatomy and restricted vascular access. The leadless technology appears a suitable and attractive alternative for this population. We describe a patient with single ventricle physiology who successfully underwent implantation of a leadless pacemaker.

Atrial Fibrillation Ablation in Adults With Repaired Congenital Heart Disease

The incidence of atrial fibrillation (AF) in congenital heart disease (CHD) adults has increased in the past decades due to a longer life expectancy of this population where the subjects are exposed to cardiac overflow, overpressure and structural changes for years. The literature regarding AF ablation in repaired CHD adults emphasizes the importance of intracardiac echocardiography (ICE) to perform the transseptal puncture and the ablation procedure in the left atrium (LA), both effectively and safely. In small case control studies, where the predominant congenital cardiomyopathy was the atrial septal defect, the most common strategy for ablation was antral isolation of the pulmonary veins showing results, at one year follow-up, similar to those in the general population. The positive results of AF ablation so far, in this specific population, widen the range of therapeutic options for a group of patients whose only chance has been pharmacological treatment, which has proved to be inefficacious in most of the cases and not free from adverse events.

Transbaffle catheter ablation of atrial re-entrant tachycardia within the pulmonary venous atrium in adult patients with congenital heart disease

AIMS

Catheter ablation of atrial re-entrant tachycardia in patients after atrial switch procedure for transposition of the great arteries or with a Fontan circulation is technically challenging if the critical part of the re-entry circuit is located within the pulmonary venous atrium (PVA). We report our experience in transbaffle access (TBA) to the PVA for ablation of atrial re-entrant tachycardia focusing on technical details.

METHODS AND RESULTS

In eight patients, six after Mustard procedure and two with a Fontan circulation, endocardial mapping of atrial re-entrant tachycardia revealed the critical part of the re-entry circuit within the PVA. A total of 10 ablation procedures were performed. Detailed angiographic assessment of the anatomy of the systemic and pulmonary venous atria was performed prior to baffle puncture. Transbaffle access was successfully established with a standard transseptal needle in 9 of 10 procedures. No major complications occurred. At the end of the procedure and the removal of the transseptal sheath, there was no residual shunt in any patient.

CONCLUSION

Transbaffle access to the PVA for ablation of atrial re-entrant tachycardia is feasible, less invasive than alternative approaches and can be safely applied in patients after Mustard procedure or with a Fontan circulation. However, the rigidity of prosthetic material may preclude baffle puncture at least in a subset of those patients.

Usefulness of a crista catheter for 3-dimensional electroanatomical mapping of complex right atrial tachyarrhythmias

PURPOSE

Right atrial (RA) tachyarrhythmias are not rare in patients with congenital heart disease and a history of cardiac surgery. This study investigated the usefulness of a crista catheter for 3-dimensional electroanatomical mapping of RA tachyarrhythmias.

METHODS

We consecutively included 35 patients (age, 43.2 ± 15.6 years; 15 men) who underwent an electrophysiological study with 3-dimensional electroanatomical mapping for RA tachycardia or flutter. In 13 patients with atrial flutter, we recorded and compared the electrical sequence in the anterior and posterior portions of the RA lateral wall. We used a crista catheter as a mapping catheter for 3-dimensional mapping in 12 patients (crista group), a lasso catheter in 12 patients (lasso group), and an ablation catheter in 11 patients (ablation group). We compared the 3-dimensional mapping points, time, and speed (mapping points per minute) among the groups.

RESULTS

Atrial flutter was confirmed as cavotricuspid isthmus-dependent in all patients whose two atrial electrical sequences were the same direction and as atypical (including scar-related and dual-loop) in all patients whose sequences were in the opposite direction. Mapping speed in the crista group was significantly faster than in the lasso and ablation groups: median (interquartile range) 44.0 (35.5-69.4) points/min, 23.7 (17.8-29.8) points/min, and 8.2 (4.8-11.0) points/min, respectively (p = 0.001).

CONCLUSIONS

A crista catheter is useful for high-density 3-dimensional electroanatomical mapping of complex RA tachyarrhythmias. Comparison of the electrical sequences in the anterior and posterior portions of the RA lateral wall is helpful for differentiating between cavotricuspid isthmus-dependent and atypical atrial flutter.

Technology update: intracardiac echocardiography - a review of the literature

The development of new imaging tools helps in better investigation of cardiac structures and function by showing detailed images during interventional procedures. Intracardiac echocardiography plays a pivotal role as an intraoperative real-time imaging tool during invasive cardiac procedures. Initially, this echocardiographic technique was particularly useful when transthoracic image quality was insufficient and to avoid general anesthesia for transesophageal imaging. Nowadays, intracardiac echocardiography is routinely used in several cardiac invasive laboratories to support several types of procedures, such as extraction and implantation of cardiac devices, electrophysiological mapping, ablation, and endomyocardial biopsies. This review gives an overview of the basic principles of intracardiac echocardiography and examines its applications in the different settings of invasive cardiology.

Utility of noninvasive arrhythmia mapping in patients with adult congenital heart disease

Arrhythmia management in patients with adult congenital heart disease (ACHD) is a challenge on many levels, as tachycardic episodes may lead to hemodynamic impairment in otherwise compensated patients even if episodes are only transient. Recently several technical advances, including 3-dimensional (3D) image integration, 3D mapping, and remote magnetic navigation, have been introduced to facilitate curatively intended ablation procedures in patients with ACHD. This review attempts to outline the role of a novel technology of simultaneous, noninvasive mapping in this patient cohort, and gives details of the authors' single-center experience.