Electroanatomic mapping of entrained and exit zones in patients with repaired congenital heart disease and intra-atrial reentrant tachycardia

Outcomes of catheter ablation of atrial tachyarrhythmia guided exclusively by activation mapping

INTRODUCTION

Complex atrial tachyarrhythmias (CATs) are commonly observed in patients with prior catheter ablation or cardiac surgery. These arrhythmias are challenging to map and ablate. Historically, entrainment mapping was utilized to characterize CAT. With the advent of high-definition mapping (HDM), full visualization of the CAT circuit is possible which may obviate the need for entrainment mapping.

METHODS

We sought to investigate the outcomes of catheter ablation of CAT guided only by HDM. Consecutive patients who underwent CAT ablation from 2017 to 2021 were included in our study (excluding right atrial tachyarrhythmias). Patients were sorted by the type of mapping performed. Group I consisted of patients where HDM alone was utilized with no attempt of entrainment. Group II consisted of patients where both entrainment and HDM were utilized.

RESULTS

A total of 67 patients were included in our study, with 40 patients in HDM group (I) and 27 patients in entrainment group (II). No statistically significant difference regarding 1-year freedom from atrial arrhythmias was found between the two groups (80% vs 77.8%, p = 0.819). Four CATs were terminated by entrainment during procedure versus none in the HDM-only group (p = 0.011).

CONCLUSIONS

CAT ablation with HDM alone yielded similar 1-year freedom from atrial arrhythmias compared to ablation with HDM and entrainment. Entrainment combined with HDM was associated with higher undesired CAT interruption rate. Further validation is needed with randomized control trials.

Mapping and Ablation of Atypical Atrial Flutters

Atypical atrial flutters are complex, hard-to-manage atrial arrhythmias. Catheter ablation has progressively emerged as a successful treatment option with a remarkable role played by irrigated-tip catheters and 3D electroanatomic mapping systems. However, despite the improvement of these technologies, the ablation results may be still suboptimal due to the progressive atrial substrate modification occurring in diseased hearts. Hence, a patient-tailored approach is required to improve the long-term success rate in this scenario, aiming at achieving specific procedure end points and detecting any potential arrhythmogenic substrate in each patient.

Ablation of intra-atrial reentrant tachycardias in adults with congenital heart disease: islands, isthmuses, channels, and walls

PURPOSE OF REVIEW

The adult congenital heart patient population is rapidly growing due to increasing survival rates, and they often face chronic physiologic challenges as sequalae of both their defects and repairs. Among the most common sequalae are arrhythmias. Here we describe intra-atrial reentrant tachycardia (IART), one of the most commonly seen arrhythmias in the adult congenital heart population, and the approaches to successful ablation in adult congenital heart patients.

RECENT FINDINGS

IART has increasing ablation success rates due to the increasing exposure of electrophysiologists to congenital cases, advances in technology, and the increasing application of both our pediatric congenital knowledge and adult acquired knowledge to the adult congenital population.

SUMMARY

IART is a frequently seen arrhythmia in the adult congenital population, and it can have life-threatening consequences in the setting of congenital disease. Ablation techniques and treatment rates have improved over time, despite the challenges these cases present to clinicians; success of the ablation depends on careful, often creative, preplanning, and understanding of the complex individualized anatomy and circuits of the patient.

Prediction of Recurrent Atrial Tachyarrhythmia After Receiving Atrial Flutter Ablation in Patients With Prior Cardiac Surgery for Valvular Heart Disease

Background: Surgical scars cause an intra-atrial conduction delay and anatomical obstacles that facilitate the perpetuation of atrial flutter (AFL). This study aimed to investigate the outcome and predictor of recurrent atrial tachyarrhythmia after catheter ablation in patients with prior cardiac surgery for valvular heart disease (VHD) who presented with AFL.

Methods: Seventy-two patients with prior cardiac surgery for VHD who underwent AFL ablation were included. The patients were categorized into a typical AFL group (n = 45) and an atypical AFL group (n = 27). The endpoint was the recurrence of atrial tachyarrhythmia during follow-up. A multivariate analysis was performed to determine the predictor of recurrence.

Results: No significant difference was found in the recurrence rate of atrial tachyarrhythmia between the two groups. Patients with concomitant atrial fibrillation (AF) had a higher recurrence of typical AFL compared with those without AF (13 vs. 0%, P = 0.012). In subgroup analysis, typical AFL patients with concomitant AF had a higher incidence of recurrent atrial tachyarrhythmia than those without it (53 vs. 14%, P = 0.006). Regarding patients without AF, the typical AFL group had a lower recurrence rate of atrial tachyarrhythmia than the atypical AFL group (14 vs. 40%, P = 0.043). Multivariate analysis showed that chronic kidney disease (CKD) and left atrial diameter (LAD) were independent predictors of recurrence.

Conclusions: In our study cohort, concomitant AF was associated with recurrence of atrial tachyarrhythmia. CKD and LAD independently predicted recurrence after AFL ablation in patients who have undergone cardiac surgery for VHD.

Lateral tunnel Fontan atrial tachycardia ablation trans-baffle access is not mandatory as the initial strategy

BACKGROUND

Mapping and ablation of atrial tachycardia (AT) is commonly performed in lateral tunnel Fontan (LTF) patients, yet there is little information on the need of baffle puncture to access the pulmonary venous atrium (PVA). This study aimed to evaluate the most common chamber location of critical sites for majority of AT in LTF patients.

METHODS

Consecutive LTF patients underwent catheter-based high-density mapping and ablation of AT from Nov. 2015 to Mar. 2019. Critical sites were identified by a combination of activation and entrainment mapping. Acute procedural success was defined as AT termination with ablation and non-inducibility of any AT. Predictors for ablation failure were evaluated in retrospect.

RESULTS

Fifteen catheter ablation procedures were performed in 9 patients. A total of 15 clinical ATs (mean TCL 369 ± 91 ms) were mapped. The mechanism was macro re-entry in 11 (73%) and micro re-entry in 2. In 11 ATs (73%), 94 ± 5% of tachycardia cycle length (TCL) were mapped inside the tunnel. The commonest site of successful ablation in the tunnel was on the lateral wall (60%). Trans-baffle access was obtained during 5 of 15 procedures (33%). Overall, procedural success was achieved in 9 of 15 procedures (60%). There were no complications. Recurrence of AT was 42% over a follow-up period of 4.3 ± 3.2 years. Faster TCL of 200-300 ms showed a trend towards ablation failure, (OR 17, 95% CI 0.7 to 423, p = 0.08).

CONCLUSIONS

Catheter ablation can be performed effectively for ATs in LTF patients usually from inside the tunnel. ATs with critical sites in the PVA are uncommon. This information will help plan ablation in LTF patients without resorting to initial trans-baffle access.

[Three-dimensional mapping : Special aspects and new features of CARTO®]

The precise target location for radiofrequency energy delivery was initially determined through electrophysiological signals and with the help of fluoroscopy. The introduction of the 3D mapping system CARTO® (Biosense Webster Inc., Diamond Bar, CA, USA) in recent years for radiofrequency ablation of arrhythmias has provided new therapeutic options. These improvements have led to reduced procedural and fluoroscopic times. The introduction of new software and technology has also improved clinical outcome and helped to understand the substrate of complex arrhythmias. This article provides an overview of the development of the CARTO® system and presents new features of the system.

Atrial flutter in a patient with atrial septal defect and anomalous venous drainage : unusual approach for ablation

Atrial flutter ablation in CHD (Congenital Heart Disease) patients is a challenging procedure because of the possibility of multiple circuits. Electroanatomical mapping and pacing maneuvers are crucial to determine critical isthmus. Moreover, vascular abnormalities and residual cardiac defects need to be known before the ablation to decide the better strategy for ablation.

Substrate characteristics and ablation outcome of left atrial tachycardia in rheumatic mitral valve disease

BACKGROUND

Right atrial tachycardia (AT) is a common arrhythmia postsurgical valve replacement in patients with rheumatic heart disease (RHD). However, the substrate and the mechanism of left AT in such patients and the ablation efficacy is less known.

METHODS AND RESULTS

Twenty-seven RHD patients with AT were enrolled in this study; nine of them (33%) had left AT. Five and four patients had left AT during the first and second procedure, respectively. A spontaneous scar in the left posterior wall was identified in all patients, and obvious anterior scar in three patients. Dual-roof-dependent AT was found in three patients and macroreentry AT surrounding right pulmonary vein was identified in one patient, two of whom had left anterior scar. Three patients had AT circuit going around the mitral annulus, one of whom had left anterior scar. Entrainment pacing at different sites confirmed the mechanism of these macroreentries. Two patients had a focal origin, one was localized in posterior wall at the edge of the scar and the other one was originated from the left septum with normal voltage. After a mean follow-up of 27.4 ± 7.9 months, the left AT group had a similar recurrence rate compared with the right AT group alone (67% vs 56%, P = 0.58). In the left AT group, 11% of patients had AT recurrence and 56% of patients developed atrial fibrillation.

CONCLUSION

Left atrial AT can occur in RHD patients postmitral valve replacement. Catheter ablation is feasible with high acute success rate. The incidence of late development atrial fibrillation is considerable after successful ablation.

Catheter Ablation of Incisional Atrial Tachycardia

Tachycardias after atrial incisions represent frequent and serious problem. The majority of them are based on a re-entry electrical activation around a combination of anatomic and surgically created obstacles. Considering significant progress of cardiovascular surgery during the last decade along with potential large amount of open-heart procedures in the near future the number of incisional tachycardias has a tendency to increase. The aim of this work was to quantify the magnitude of the problem, characterize the tachycardias after different surgical operations and to analyze possible interventional treatment strategies. Nowadays evolution of mapping and ablation technologies may contribute to radically treatment of this type of arrhythmias while there are still a lot of issues that should be solved to improve the results of interventional treatment of incisional tachycardias.

The Long-Term Management of Children and Adults with a Fontan Circulation: A Systematic Review and Survey of Current Practice in Australia and New Zealand

Although long-term survival is now the norm, Fontan patients face significant morbidity and premature mortality. Wide variation exists in long-term Fontan management. With an aim of improving their long-term management, we conducted a systematic review to identify best available evidence and gaps in knowledge for future research focus. We also surveyed cardiologists in Australia and New Zealand managing Fontan patients, to determine the alignment of current local practice with best available evidence. A systematic review was conducted using strict search criteria (PRISMA guidelines), pertaining to long-term Fontan management. All adult congenital and paediatric cardiologists registered with The Australia and New Zealand Fontan Registry were invited to respond to an online survey. Reasonable quality evidence exists for non-inferiority of aspirin over warfarin for thromboprophylaxis in standard-risk Fontan patients. No strong evidence is currently available for the routine use of ACE inhibitors, beta blockers or pulmonary vasodilators. Little evidence exists regarding optimal arrhythmia treatment, exercise restriction/prescription, routine fenestration closure, elective Fontan conversion and screening/management of liver abnormalities. Although pregnancy is generally well tolerated, there are high rates of miscarriage and premature delivery. Thirty-nine out of 78 (50 %) cardiologists responded to the survey. Heterogeneity in response was demonstrated with regard to long-term anti-coagulation, other medication use, fenestration closure and pregnancy and contraception counselling. Substantial gaps in our knowledge remain with regard to the long-term management of Fontan patients. This is reflected in the survey of cardiologists managing these patients. We have identified a number of key areas for future research.

Heart Failure in Adult Congenital Heart Disease: Nonpharmacologic Treatment Strategies

In early stages, heart failure (HF) in adult congenital heart disease (ACHD) remains an elusive diagnosis. Many ACHD patients seem well-compensated owing to chronic physical and psychological adaptations. HF biomarkers and cardiopulmonary exercise tests are often markedly abnormal, although patients report stable health and good quality of life. Treatment differs from acquired HF. Evidence for effective drug therapy in ACHD-related HF is lacking. Residual ventricular, valvular, and vascular abnormalities contribute to HF pathophysiology, leading to an emphasis on nonpharmacologic treatment strategies. This article reviews emerging perspectives on nonpharmacologic treatment strategies, including catheter-based interventions, surgical correction, and palliative care.

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.

[Interventional treatment of tachyarrhythmia in children with congenital heart disease]

In children and adolescents with congenital heart disease (CHD) tachyarrhythmia occurs more frequently compared to patients with otherwise normal hearts. Arrhythmia substrates may be a natural part of certain congenital cardiac malformations or may result from long lasting myocardial deterioration as a result of CHD and/or cardiac surgery. Treatment of tachycardia is more frequently required even in early childhood, as the impact on quality of life, morbidity and mortality is higher due to an often reduced hemodynamic tolerance. Over the past 20 years interventional electrophysiology has been established as the therapy of choice for the majority of chronic or chronically recurrent tachycardia even in children with CHD. The success and risks of treatment are predominantly influenced by the individual expression of the cardiac anomaly and, if surgery has been performed, the highly variant postoperative anatomy. Introduction of 3D electroanatomical mapping systems together with modern cardiac imaging tools have significantly contributed to an improved understanding, particularly in postoperative tachycardia. Despite such progress, success rates are lower and recurrences are more frequent compared to patients without CHD. Complex and often multiple tachycardia courses account for the still limited performance as well as a frequently insufficient lesion formation with the use of radiofrequency current in the hypertrophic and fibrotic myocardium. Electrophysiology in children and adolescents, particularly if CHD is present, represents a highly specialized discipline requiring a high expertise in CHD, CHD surgery and cardiac electrophysiology and is ideally imbedded within an interdisciplinary cardiological and cardiosurgical setting.

Arrhythmias in adult congenital heart disease

Recent advances in pediatric cardiology and cardiac surgery have allowed a rapidly expanding population of patients with congenital heart disease to thrive well into their adult years. Often after prolonged uneventful clinical courses as children and adolescents, arrhythmias may surface later in life. These arrhythmias are a major source of morbidity. In addition, sudden death is the leading cause of mortality in adult patients with congenital heart disease. This review highlights the various types of brady- and tachyarrhythmias encountered in the more common forms of adult congenital heart disease and explores prognostic implications and therapeutic options.

Importance of tachycardia cycle length for differentiating typical atrial flutter from scar-related in adult congenital heart disease

BACKGROUND

 Radiofrequency catheter ablation (RFCA) for intraatrial reentrant tachycardia (IART) in congenital heart disease (CHD) remains difficult.

METHODS

 Thirty-four consecutive adult patients (age, 37.6 ± 12.8 years; male, 21) with previously repaired CHD and IART underwent an electrophysiological study and RFCA. CHD included atrial septal defect (ASD, n = 14), tetralogy of Fallot (n = 11), ventricular septal defect (n = 4), pulmonary atresia (n = 2), atrioventricular septal defect (n = 1), transposition of the great arteries (n = 1), and double-outlet right ventricle (n = 1).

RESULTS

 Duration of CHD repair to IART onset was 19.1 ± 8.5 years. Thirty and four patients had single- and double-loop reentrant tachycardia, respectively. Among the total of 38 IARTs, which were mapped, 22 (57.9%) and 13 (34.2%) IARTs were cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) and scar-related AFL, respectively. Typical AFL electrocardiography findings including definite sawtooth appearance in inferior leads and positive F wave in lead V1 were observed in only 12 of 21 patients (57.1%) with CTI-dependent AFL. CTI-dependent AFL had a significantly longer tachycardia cycle length (TCL) than scar-related AFL (267.6 ± 34.4 ms and 235.9 ± 37.0 ms, respectively; P = 0.031). TCL > 250 ms had 79% sensitivity as the cutoff value for differentiating CTI-dependent from scar-related AFL. The acute success rates of RFCA in CTI-dependent and scar-related AFLs were 85.7% and 90.0%, respectively. The recurrence rates in CTI-dependent and scar-related AFLs were 11.1% and 11.1%, respectively, during a follow-up of 21.2 ± 28.3 months.

CONCLUSIONS

 CTI-dependent AFL was the most common IART in adult patients with repaired CHD and was easily manageable by RFCA. TCL might help to differentiate CTI-dependent AFL from other IARTs.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

Higher rate of recurrent atrial flutter and atrial fibrillation following atrial flutter ablation after cardiac surgery

INTRODUCTION

Atrial flutter (AFL) is common after cardiac surgery. However, the types of post-cardiac surgery AFL, its response to catheter-based radiofrequency ablation, and its relationship to atrial fibrillation (AF) are unknown.

METHODS AND RESULTS

We retrospectively studied all patients who underwent mapping and ablation for AFL after cardiac surgery from January 1990 to July 2004. One hundred randomly selected patients without prior cardiac surgery (PCS) who underwent mapping and ablation of AFL served as the control population. A total of 236 patients formed the study population (mean age 62 + 13 years, 22% female) and 100 patients formed the control population (mean age 60 + 13 years, 25% female). The majority of patients without PCS had cavo-tricuspid isthmus (CTI)-dependent AFL when compared to patients with PCS (93% vs 72%, respectively, P < 0.0001). In contrast, scar-related AFL was more common in patients with PCS as compared to patients without PCS (22% vs 3%, P < 0.0001). Predictors of scar related AFL in multivariable regression analysis included PCS and left-sided AFL. Acute success rates and complications were similar between the groups. When compared to patients with AFL ablation without PCS, those that had AFL after PCS had higher rates of recurrence of both AFL (1% vs 12%, P < 0.0001; mean time to recurrence 1.85 years) and AF (16% vs 28%, P = 0.02; mean time to recurrence 2.67 years).

CONCLUSION

Despite ablation of AFL, patients with PCS have a higher rate of AFL and AF when compared to patients without PCS who underwent ablation of atrial flutter during long-term follow-up.

Transcatheter ablation of arrhythmias associated with congenital heart disease

The improvement of surgical techniques resulted in significant life prolongation of many young patients with congenital heart disease (CHD). However, as these patients reach adulthood, their risk for late complications associated with surgery is also increased. One of the most difficult challenges associated with CHD is the high incidence of cardiac arrhythmias that arise from either the myocardial substrate created by abnormal physiology (pressure/volume changes, septal patches, and suture lines) or the presence of surgical scar. Catheter ablation is proven to be effective in treating atrial and ventricular arrhythmias in structurally normal hearts, and has also been used to treat arrhythmias in adults with congenital heart disease. In this review we provide an overview about diagnostic challenges, mapping and ablation techniques and outcome of patients undergoing transcatheter ablation procedures.