Intra-atrial Reentrant Tachycardia Research Articles

Electrophysiological assessment of atrial tachycardia substrates in patients with repaired tetralogy of Fallot

Abstract Introduction Adults with repaired tetralogy of Fallot (rToF) are most often referred to Adult Congenital Heart Disease centers for atrial tachycardia (AT) and radiofrequency catheter ablation (RFCA) is often required. A systematic evaluation of the mechanisms and recurrences of arrhythmias in these patients is lacking. Methods 28 patients with rToF referred for catheter ablation to the Interventional Electrophysiology Unit of our center between January 2013 and January 2023 were evaluated. Pts underwent electrophysiologic study (EPS) with 3D electroanatomic high density mapping. Evaluation of right atrial bipolar voltage and activation mapping of the AT was performed. Intra-atrial re-entrant tachycardias (IART), focal AT (FAT), other. Activation mapping was performed to identify the critical isthmus for IART. FATs were localized according to the earliest unipolar signal. Whenever possible, all the induced tachycardias were treated besides the arrhythmia which represented the clinical indication to EPS. RFCA was aimed at the earliest activation point for FAT and at the critical isthmus for IART, anchoring lesion to fixed obstacles (valve annuli or atriotomy scar). All patients provided written informed consent for participating in the study. Results Among 28 adult (age 47±13 years) patients (females n=14, 50%), 53 AT were documented: 34 (64%) IART, 11 (21%) FAT and 8 (15%) atrial fibrillation (AF). Mean tachycardia cycle length (excluding AF) was 307±95 ms. At least 2 ATs were induced in 12 pts during index EPS. Among IARTs, incisional IART (IARTinc, atriotomy and superior and inferior vena cava orifices, SVC and IVC, respectively) was the prevalent critical part of the circuit (n=22, 52%), while CTI was the second mechanism (n=20, 48%). In three pts, due to non-inducibility, a pre-emptive lesion set comprising in one case CTI and in two cases CTI+SVC-atriotomy-IVC line was performed. 2 patient underwent scheduled pulmonary veins isolation and CTI ablation. Among FAT, in 3 cases the AT was mapped in the coronary sinus, in two at the tricuspid annulus, in the remaining at the crista terminalis, at the right appendage base, at the posterolateral incision scar or between atriotomy and SVC. In 6 patients AF was induced but not ablated. During a median follow up of 23 months (interquartile range, 6-37) recurrence occurred in 8 pts (18% of pts, 15% of tachycardias). Patients with recurrences were younger (43±7 vs. 48±17 y, p=0.04); no differences were found according to critical isthmus location (4 CTI and 4 IARTinc, 50%, p=ns). Conclusions Among rToF pts with AT, IART is the prevalent mechanism and atriotomy scar is the prevalent critical isthmus. FAT location is much more variable. Atrial fibrillation burden is not negligible. Long-term freedom from AT in this clinical setting is encouraging.

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.

Use of apixaban in adults with congenital heart disease and atrial arrhythmias: The PROTECT-AR study

BackgroundAdults with congenital heart disease (ACHD) and atrial arrhythmias (AA) face an increased risk of thromboembolic events. Limited data exist on the use of non-vitamin K oral anticoagulants for thromboprophylaxis in ACHD. We aimed to assess the effectiveness and safety of apixaban in ACHD patients with AA. MethodsPROTECT-AR (NCT03854149) was a prospective, multicenter, observational study conducted from 2019 to 2023. ACHD patients with atrial fibrillation, atrial flutter, or intra-atrial re-entrant tachycardia on routine apixaban treatment were included. The historical control group consisted of patients previously on vitamin K antagonist (VKA), who were analyzed prior to their transition to apixaban. The primary effectiveness endpoint was the composite of stroke or thromboembolism. The primary safety endpoint was major bleeding. ResultsThe study enrolled 218 ACHD patients with AA on apixaban, of which 73 were previous VKA users. The analysis covered 527 patient-years of prospective exposure to apixaban and 169 patient-years of retrospective exposure to VKA. The annualized rate of stroke or thromboembolism was 0.6% in the apixaban group and 1.8% in the VKA group (absolute difference − 1.2%; upper limit of one-sided 95% confidence interval [CI] 0.9%, lower than the predefined non-inferiority margin of +1.8%, Pnon-inferiority < 0.001). The annualized rate of major bleeding was 1.5% in the apixaban group and 2.4% in the VKA group (hazard ratio 0.64; 95% CI 0.19–2.10, P = 0.48). ConclusionIn ACHD patients with AA, routine apixaban use exhibited a non-inferior rate of stroke or thromboembolism compared to historical VKA use, alongside a similar rate of major bleeding.

Arrhythmias in Patients with Congenital Heart Disease: An Ongoing Morbidity.

With the aging of congenital heart disease (CHD) patients, the burden of arrhythmias is expanding. Atrial arrhythmias, especially intra-atrial reentrant tachycardia and atrial fibrillation, are the most prevalent forms of arrhythmia. Managing comorbidities, such as obesity, using pharmacotherapy, including antiarrhythmics and anticoagulants, and ablation therapy has become the cornerstone of arrhythmia management. Ventricular tachycardias are also not rare; however, except for tetralogy of Fallot patients, recommendations for the use of implantable cardioverter defibrillators for primary prevention in other CHD patients are still not well established. Patients with CHD might also present with atrioventricular blockages because of their anatomy or following a surgical procedure. The scope of this article is to review the current knowledge and discuss the future directions regarding arrhythmia management in CHD patients.

Safety and efficacy of apixaban for the prevention of thromboembolism in adults with congenital heart disease and atrial arrhythmias: a prospective cohort study with historical control comparison

Abstract Introduction In adults with congenital heart disease (ACHD), atrial arrhythmias (AA) confer an increased risk of thromboembolic events. Data regarding treatment with non-vitamin K oral anticoagulants (NOACs) of patients with ACHD and AA are limited. Methods A prospective, multicenter, observational study of ACHD patients with AA (atrial fibrillation, atrial flutter, or intra-atrial re-entrant tachycardia) treated with apixaban from 2019 to 2022 was performed (PROTECT-AR, NCT03854149). Comparisons were made with a historical vitamin-K antagonist (VKA) treatment cohort from 2002 to 2014. The primary efficacy endpoint was the composite of stroke or thromboembolism. The primary safety endpoint was major bleeding. Results The apixaban-treated cohort consisted of 215 patients (median follow-up 28 months) and the historical VKA-treated ­cohort consisted of 229 patients with ACHD and AA (median follow-up 48 months). The burden of age and comorbidities was higher in the apixaban versus the VKA treatment group (Table). Comparing the apixaban with the VKA treatment group yielded no significant differences in the annualized rate of stroke or thromboembolism (1.2% vs. 1.4%, respectively; p=0.24) and major bleeding (1.2% vs. 4.4%, respectively; p=0.08) (Figure). Conclusion In ACHD patients with AA treated with apixaban as part of routine care, the risk of major thromboembolic and bleeding events was low. This risk was comparable with historical cohort data on VKA. Prospective studies directly comparing NOAC and VKA-treated patients are needed.

Abstract 15341: A Prospective Study on the Safety and Effectiveness of Apixaban for the Prevention of Thromboembolism in Adults With Congenital Heart Disease and Atrial Arrhythmias: The PROTECT-AR Study

Introduction: In adults with congenital heart disease (ACHD), atrial arrhythmias (AA) confer an increased risk of thromboembolic events. Limited data exist on non-vitamin K oral anticoagulant (NOAC) treatment for ACHD. We aimed to assess the effectiveness and safety of apixaban in ACHD patients with AA. Methods: PROTECT-AR (NCT03854149) was a prospective, multicenter, observational study conducted from 2019 to 2023. ACHD patients with atrial fibrillation, atrial flutter, or intra-atrial re-entrant tachycardia, who were routinely treated with apixaban, were included. The primary efficacy endpoint was the composite of stroke or thromboembolism. The primary safety endpoint was major bleeding. Patients who were previously on vitamin K antagonists (VKAs) before transitioning to apixaban served as a historical control group. Results: In total, 218 patients with ACHD and AA on apixaban (previous VKA users 34.9%) were included (mean age 51±17 years; 45.9% male; predominantly moderate complexity). Over a mean follow-up of 2.4±1.3 years, the rate of stroke or thromboembolism was 0.57% [95% confidence interval (CI): 0.15-1.55] and the rate of major bleeding was 1.52% [95%CI: 0.71-2.88] per patient-year, respectively. In the subset of patients who were previously on VKA, the risk of the primary endpoints did not differ significantly between apixaban and VKA-treatment periods (Figure). Conclusion In ACHD patients with AA on routine apixaban treatment, the risk of major thromboembolic and bleeding events was low. Among prior VKA users, the risk of adverse events during the apixaban-treatment period was comparable to that during the VKA-treatment period. Prospective studies directly comparing NOAC and VKA-treated patients are needed.

Late development of intra-atrial reentrant tachycardia in lateral tunnel Fontan patients and the preventive role of prophylactic cryoablation

ObjectiveIntra-atrial reentrant tachycardia is an important late-onset complication in patients undergoing the Fontan procedure. However, the protective effects of prophylactic cryoablation against late-onset intra-atrial reentrant tachycardia are unclear. This study investigated the late development of intra-atrial reentrant tachycardia in patients undergoing the lateral tunnel Fontan procedure and the role of prophylactic cryoablation. MethodsThis was a single-center retrospective cohort study of patients who underwent the lateral tunnel Fontan procedure between 1988 and 2003. Univariate and multivariable competing risks regression models were used to determine the associations of prophylactic cryoablation and covariates with the outcomes of interest: late-onset intra-atrial reentrant tachycardia, all-cause mortality, and cardiovascular mortality. ResultsIn total, 130 patients who underwent the lateral tunnel Fontan procedure, 30 of whom had undergone prophylactic cryoablation, were included in this study and followed up for a median of 23.6 years (interquartile range, 17.7-26.5). Intra-atrial reentrant tachycardia was identified in 14 patients (10.8%), none of whom underwent prophylactic cryoablation. The median Fontan-to-intra-atrial reentrant tachycardia time was 17.2 years (interquartile range, 11.1-23.1). Prophylactic cryoablation was protective against late-onset intra-atrial reentrant tachycardia (P < .0001) and cardiovascular mortality (P < .0001) in the type 3 test. ConclusionsNone of the patients who underwent prophylactic cryoablation developed late-onset intra-atrial reentrant tachycardia during a median follow-up time of 22.9 years. Our study demonstrated that prophylactic cryoablation was effective in preventing late-onset intra-atrial reentrant tachycardia and cardiovascular mortality in patients undergoing the lateral tunnel Fontan.

Use of the advisor™ HD Grid mapping catheter in transcatheter ablation of atrial arrhythmias in palliated CHD and children without CHD.

In this study, we describe our experience utilising Advisor™ High Density (HD) Grid mapping catheter in transcatheter ablation of intraatrial re-entrant and focal atrial tachycardias with or without CHD. Forty-five consecutive patients with intraatrial re-entrant and focal atrial tachycardia who underwent a transcatheter ablation procedure by using Advisor™ HD Grid mapping catheter and high-density mapping system in our hospital from January 2017 to January 2023 were included into the study. The mean age of the patients was 14.2 ± 7.3 years (6-32 years), and the mean weight was 48.3 ± 16.2 kg (22-83 kg). Of the total 45 patients, 21 were intraatrial re-entrant tachycardia and 25 were focal atrial tachycardia. Of the 21 re-entrant circuits, 15 were classified as cavotricuspid isthmus-dependent and 5 were non-cavotricuspid isthmus-dependent. In one patient, two re-entrant circuits were identified. A transbaffle ablation was successfully performed from the left atrium in one patient. Of the 25 focal atrial tachycardia, 19 were from right atrium and 6 were from left atrium. A cryoablation was performed in only one patient and radiofrequency ablation in others. The mean procedure time was 180 ± 64 minutes. The mean follow-up period was 69.3 ± 35.3 months. Acute success was 95.5%. Recurrence was noted in two patients (4.4%). Advisor™ HD Grid mapping catheter was found to be safe and achieved an acceptable success in transcatheter ablation of patients with intraatrial re-entrant tachycardia and focal atrial tachycardias.

An unmet need: arrhythmia detection by implantable loop recorder in the systemic right ventricle.

Patients with systemic right ventricles are at high risk of sudden cardiac death. Arrhythmia is a significant risk factor. Routine Holter monitoring is opportunistic with poor adherence. The aim of this study was to determine if continuous rhythm monitoring with an implantable loop recorder (ILR) could allow early detection of clinically important arrhythmias. Implantable loop recorder implantation was offered to patients with atrial switch repair for transposition of the great arteries. Recordings were made with symptoms or, automatically for pauses, significant bradycardia or tachycardia and reviewed by the multi-disciplinary team. Twenty-four out of 36 eligible patients underwent ILR implantation with no complication. Forty-two per cent had preserved ventricular function, 75% were NYHA functional class I, 88% had low sudden cardiac death risk, 33% had previous intra-atrial re-entrant tachycardia (IART), and none had known conduction disease. Eighteen out of 24 (75%) patients made 52 recordings (52% automated) over 39.5 months (1.6-72.5). Thirty-two out of 52 (62%) recordings in 15/24 (63%) of the cohort were clinically significant and included sinus node disease (two patients), atrioventricular block (two patients), IART (seven patients), and IART with sinus node disease or atrioventricular block (four patients). Implantable loop recorder recordings prompted medication change in 11 patients [beta-blockers (n = 9), anti-coagulation (n = 5), and stopping anti-coagulation (n = 1)] and device therapy recommendation in seven patients [five pacemakers (three: atrioventricular block) and two defibrillators]. Two patients declined intervention; one suffered an arrhythmic death. Intra-atrial re-entrant tachycardia and clinically relevant conduction disease were detected in patients irrespective of sudden cardiac death risk. Continuous monitoring with an ILR in patients with systemic right ventricle following atrial switch detects clinically relevant arrhythmias that impact decision-making. In this cohort, clinically relevant arrhythmias did not correlate with sudden cardiac death risk.

Atrial Arrhythmias in Adults with Fontan Palliation.

Single ventricle physiology is a rare form of congenital heart disease and was, historically, a uniformly lethal condition. However, the atriopulmonary Fontan operation, and its successive iterations, the lateral tunnel and extracardiac conduit Fontan, became the fundamental approach to treating single ventricle heart disease. Over time, dysrhythmias are some of the most common complications with Fontan physiology, compounding morbidity and mortality. Atrial arrhythmias are prevalent in the Fontan population and occur in about 15-60% of patients with Fontan palliation, increasingly with age. Diagnosing atrial arrhythmias in patients with Fontan palliation may be challenging because of low voltage amplitudes arising from myopathic atrial tissue making it difficult to clearly assess atrial depolarization on surface electrocardiograms (ECG), vague symptoms not suggestive of tachyarrhythmia, or atrial arrhythmia with ventricular rates below 100beats per minute. Intra-atrial reentrant tachycardia (IART) is the most common type of supraventricular tachycardia in adults with Fontan palliation. Acute management of atrial arrhythmias in patients with Fontan palliation involves prompt assessment of a patient's hemodynamic stability, anticoagulation and thrombosis risk, systemic ventricular function, and risk of sedation or anesthesia if needed. Long-term management of atrial arrhythmias is often multifactorial and may include long-term anti-arrhythmic therapy, permanent pacing, and ablation. The best approach for the management of atrial arrhythmias in adults with Fontan palliation is patient-specific and involves collaboration between congenital electrophysiologists, adult congenital cardiologists, and the patient.

C46 ELECTROPHYSIOLOGICAL ASSESSMENT OF ATRIAL TACHYCARDIA SUBSTRATES IN PATIENTS WITH REPAIRED TETRALOGY OF FALLOT

Abstract Introduction Adults with repaired tetralogy of Fallot (rToF) experience episodes of atrial tachycardia (AT) and radiofrequency catheter ablation (RFCA) is often required but systematic evaluation of the mechanisms and recurrences is lacking. Methods Between January 2013 and October 2021, 20 rToF patients with AT referred for catheter ablation were enrolled. Electrophysiologic study with 3D electroanatomic mapping with multi–electrode mapping catheters was done, with right atrial bipolar voltage and activation mapping of the AT. Three mechanisms were searched: intra–atrial re–entrant tachycardias (IART), focal (FAT), other. Critical isthmus (CI) for IART was identified with activation mapping. FATs were localized according to the earliest uni/bipolar signal. All induced AT were treated. RFCA was aimed at the earliest activation point for FAT and at the critical isthmus for IART, anchoring lesion to fixed obstacles (valve annuli or scar). Written informed consent was provided. Results Among 20 adult (age 46±14 years) and mainly females (n=11, 55%) enrolled pts, 36 AT were documented: 25 (70%) IART, 10 (27%) FAT and only 1 (3%) had a typical atrioventricular nodal reentrant tachycardia. Mean tachycardia cycle length was 307±95 ms. Two ATs were induced in 11 pts, 3 in 4 pts and 4 in 2 during index EPS. Among IART, cavo–tricuspid isthmus (CTI) was the prevalent CI (n=14, 60%), while incisional IART (IARTinc, atriotomy and superior and inferior vena cava orifices, SVC and IVC, respectively) was the second mechanism (n=9, 39%). In two pts, due to non–inducibility, a pre–emptive lesion set comprising in one case CTI and in the second case CTI+SVC–atriotomy–IVC line was performed. Among FAT, in 3 cases the AT was mapped in the coronary sinus, in two at the tricuspid annulus, other at the crista terminalis, right appendage base, posterolateral scar or between atriotomy and SVC. During a median follow–up of 23 months (interquartile range, 6–37) recurrence occurred in 8 pts (25% of pts, 22% of tachycardias). Pts with recurrences were younger (43±7 vs. 48±17 y, p=0.04); no differences were found according to critical isthmus location (4 CTI and 4 IARTinc, 50%, p=ns). Conclusions Among rToF pts with AT, IART is the prevalent mechanism and CTI is the prevalent CI; atriotomy scar, however, is involved in a substantial portion of the critical isthmuses of the IART; FAT location is much more variable. Long–term freedom from AT in this clinical setting is encouraging.

PO-03-147 EVALUATION OF A PEDIATRIC ELECTROPHYSIOLOGY CASE COMPLEXITY PREDICTION MODEL TO OPTIMIZE PROCEDURAL SCHEDULING

While operational efficiency has been evaluated in adult interventional and surgical specialties, limited data exist regarding the prediction of case complexity in the pediatric and congenital electrophysiology (EP) laboratory. To identify pre-procedural variables that predict prolonged case durations among pediatric and adult congenital patients presenting for diagnostic EP study and catheter ablation. A retrospective cross-sectional study was performed of all EP studies performed at Boston Children’s Hospital between 1/1/2015-1/1/2020 including pediatric and adult congenital heart disease patients of all ages. The primary outcome was case duration ≥180 minutes. Univariate and multivariate analyses were performed for the primary outcome using logistic regression, with a sub-analysis repeated for pediatric patients <20 years of age. During the 5-year period, 1025 patients underwent EP study and 292 (28.5%) had a case duration ≥180 minutes. Factors associated with the primary outcome on multivariate analysis were: age ≥20 years at EP study (OR 1.95, 95% CI 1.24-3.07, p 0.004), arrhythmia diagnosis of premature ventricular contractions/ventricular tachycardia (PVC/VT, OR 3.70, 95% CI 2.10-6.55, p <0.001), Fontan (OR 3.74, 95% CI 1.69-8.30, p=0.001) or Mustard/Senning physiology (OR 4.13, 95% CI 1.48-11.60, p=0.007), and the presence of non-cardiac comorbidities (OR 2.47, 95% CI 1.29-4.73, p 0.006). Restricting the analysis to pediatric patients <20 years old, factors associated with the primary outcome on multivariate analysis were an arrhythmia diagnosis of PVC/VT (OR 3.04, 95% CI 1.64-5.63, p <0.001), Fontan physiology (OR 3.13, 95% CI 1.10-8.92, p 0.033), non-cardiac comorbidities (OR 4.32, 95% CI 2.07-9.01, p <0.001), and prior ablation (OR 1.58, 95% CI 1.03-2.41, p 0.035). Intra-atrial reentrant tachycardia was not associated with prolonged case duration in either multivariate model. A weighted risk score using factors identified on multivariate analyses correctly classified procedures with prolonged case duration with reasonable accuracy (c-statistic 0.70). Age-dependent anatomic, electrophysiologic, and comorbid factors are associated with prolonged case duration in the pediatric and congenital EP laboratory. Applying a simple risk score using pre-procedural variables can discriminate cases with and without prolonged duration, and may aid in efficient procedural scheduling practices.

PO-04-150 ATRIAL TACHYCARDIA IN PATIENTS WITH REPAIRED TETRALOGY OF FALLOT: ITS CHARACTERISTICS AND THE EFFICACY OF CATHETER ABLATION

With advanced surgical techniques and patient care, many patients with repaired tetralogy of Fallot (TOF) have extended life expectancy. However, longevity is often complicated by tachyarrhythmias. In this study, we focused on atrial tachycardias (AT), its characteristics, and the effectiveness of catheter ablation. Seventy-seven patients with repaired TOF, who are treated and followed at the University of Tsukuba Hospital, were included. The patients were divided into patients with AT and without. Various clinical parameters were evaluated and compared between the two groups. Electrophysiological and electro-anatomic data were studied in patients who had AT and underwent catheter ablation. The mean age was 34± 12 years old, and 55% were females. Twenty-three patients had AT (30%). The patients with AT were older than those without AT (40± 12 vs 31± 11; P= 0.003), the left ventricular ejection fraction was lower (58± 6 vs 62± 5; P=0.006), the right atrial (RA) area (cm2) was larger (29± 14 vs 15± 5; P<0.001), the left atrial (LA) area (cm2) was also larger (19± 3 vs 16± 4; P<0.001), the RA to LA ratio was higher (1.5 vs 1; P<0.001), had a lower tricuspid annular plane systolic excursion (16± 4 vs 18± 4; P= 0.032), and a higher prevalence of restrictive physiology (35% vs 9%; P= 0.007), respectively. These parameters were obtained during maintained sinus rhythm in all patients. Twenty patients underwent catheter ablation, in which 30 AT were ablated. Low voltage area in RA was recognized in all patients using 3D electro-anatomic mappings. The mechanism of AT was intra-atrial reentrant tachycardia revolving around RA atriotomy scar from the previous surgery in 13 AT (43%), cavotricuspid isthmus dependent in 12 AT (40%), and focal activity in the remaining 5 AT (17%). After a median follow-up of 27 months, only three patients had AT recurrence. However, in one patient, the recurrent AT could not be suppressed by endocardial ablation and was successfully treated by surgical cryoablation done during pulmonary valve replacement. The patients with AT had biventricular dysfunction and larger bi-atrial size compared with those without AT. Additionally, regardless of AT mechanism, catheter ablation was an effective treatment modality in the majority of the patients.

Coherent mapping of atrial tachycardias in patients with congenital heart disease.

Coherent mapping (CM) uses a new algorithm to identify critical conduction isthmuses of atrial tachycardias (ATs). We analysed our experience of ablation of AT in patients with congenital heart disease (CHD) with this new technology. All patients with CHD who had CM of AT using the high-density mapping PENTARAY™ catheter and three-dimensional electroanatomic mapping system Carto3 between June 2019 and June 2021 were included retrospectively (n = 27). As a control group, 27 patients with CHD and mapping of AT without CM between March 2016 and June 2019 were included. In total, 54 ablation procedures were performed in 42 patients [median age 35 (interquartile range, IQR 30-48) years] and 64 ATs were induced and mapped (thereof 50 AT intraatrial re-entrant tachycardia and 14 AT ectopic AT). The median procedure duration was 180 (120-214) min and median fluoroscopy time was 10 (5.2-14) min. Acute success was 100% (27/27) in the Coherence group and 74% (20/27) in the non-Coherence group (P = 0.01). During follow-up [median 26 (12-45) months], AT recurred in 28/54 patients, thereof 15 patients needed a re-ablation procedure. Log-rank test showed no difference in recurrence rate between the two groups (P = 0.29). Three minor complications occurred (5.5%). Mapping of AT in patients with CHD using the PENTARAY™ mapping catheter and the CM algorithm led to excellent acute success. All ATs were possible to map and no complications related to the PENTARAY™ mapping catheter were observed. Thus, the use of the CM algorithm represents a promising tool in patients with CHD and complex AT.

High-density Mapping Catheter (Advisor™ HD Grid) Usage for Intra-atrial Reentrant Tachycardia Ablation in Children and Young Adult Patients with Congenital Heart Disease.

We aimed to share our experience of intra-atrial reentrant tachycardia mapping and ablation with a new grid-style multielectrode high-density mapping catheter (Advisor™ HD Grid) in pediatric and young adult patients with operated congenital heart disease. All patients with operated congenital heart disease and intra-atrial reentrant tachycardia mapping with the new grid-style catheter between October 2019 and December 2022 were included (group 1), and the results were compared to those patients who operated with conventional catheter methods before this period (group 2). All procedures were performed using the EnSite Precision 3D mapping system (Abbott Laboratories, Abbott Park, Ill, USA) with a limited fluoroscopy approach. Data were evaluated retrospectively. In group 1 (n = 16; 9 male), the median age was 21 years (10-36), compared to 19years (9-27) in group 2 (n = 10; 5 male). While irrigated radiofrequency ablation was pre-ferred in all patients, the median number of 15 lesions (8-38) in group 1 was significantly less than the median of 30 lesions (8-71) in group 2 (P =.027). The median procedure duration of 159 minutes (110-233) in group 1 was significantly shorter compared to 280 minutes (180-370) in group 2 (P <.05). Acute procedural success was achieved in all patients (16/16; 100%) in group 1 compared to 8/10 patients (80%) in group 2. During the median follow-up of 27 months (11-36), there was only 1 intra-atrial reentrant tachycardia recurrence in group 1 (1/16; 6.2%) and 2 recurrences (2/8; 25%) in group 2 during the median follow-up of 110 months (56-151). No complications related to the mapping catheter itself occurred. In the intra-atrial reentrant tachycardia ablation of children with congenital heart disease to increase procedural success and shorten the mapping duration, the utility of Advisor™ HD Grid mapping catheter seems to be a feasible alternative.

Arrhythmic Burden of Adult Survivors With Repaired Total Anomalous Pulmonary Venous Connection.

The long-term outcome of adults with repaired total anomalous pulmonary venous connection (TAPVC) is poorly documented. Therefore, the present study aims to provide current clinical data on adult survivors with repaired TAPVC focusing on arrhythmia. Clinical and imaging data (prevalence and type of arrhythmias, symptoms, surgical and medical treatment, echocardiographic and cardiac magnetic resonance haemodynamic parameters) were retrospectively collected from 8 European centres and compared between patients with and without arrhythmias. Fifty-seven patients were included (age 20 [16-67] years [female 28, 49%]). At the last follow-up, that is, 21 (8-51) years after surgery, 79% and 93% of patients were free of symptoms and cardiac medication, respectively. The prevalence of late arrhythmias was 21%; 9 (16%) patients showed intra-atrial re-entrant tachycardia (IART) and 2 (4%) ventricular arrhythmias. Patients with IART were older (P= 0.018) and 4 (7%) required antiarrhythmic medication. Three patients (5%) underwent an electrophysiological study, and another 3 (5%) underwent pacemaker implantation within 36 months after surgical correction, which were removed in 2 patients after 7 years. Early postoperative arrhythmias (P= 0.005), right ventricular dilatation (P= 0.003), and valvulopathy (P= 0.009) were more often present in patients with late IART. Adult survivors after isolated-TAPVC repair presented a high prevalence of arrhythmias. Age, right ventricular dilatation, early arrhythmias, and valvular lesions are risk factors for IART. Long-term follow-up is important as some of these currently asymptomatic patients will probably develop arrhythmias in the future.

Prevalence and Treatment Outcomes of Arrhythmias in Patients with Single Ventricle Physiology over the Age of 40 Years.

Arrhythmias are a well known complication in patients with single ventricle physiology (SVP). However, there is still a lack of data regarding arrhythmias in older patients. The aim of this study was to analyze arrhythmia type and frequency, treatment and recurrence rates in patients with SVP over the age of 40 years. Data was obtained retrospectively from clinical records. All patients &gt; 40 years with SVP with arrhythmias between 2005 and 2018 were included in the study. Treatment was classified as medical, interventional (electrophysiological studies (EPS) in combination with catheter ablation) or direct current cardioversion (DCCV). Altogether, 29 patients (11 female; mean 47.5 ± 4.6 years) with 85 arrhythmia episodes were identified. The median follow-up time was 6.3 years. Cavo-tricuspid (CTI) and non-CTI related intra-atrial reentrant tachycardia (IART) and atrial fibrillation (AF) were most common (48.2% and 37.6%, respectively). In total, 18 EPS/ablations were performed in 9 patients and 52 DCCVs in 20 patients. Acute success was 98% for DCCV and 72.2% for EPS/ablation. Recurrence rate was high (70% for DCCV and 55% for EPS). AT recurrences occurred after a median of 8 and 2.5 months, respectively. On multivariate analyses, age was the only risk factor for arrhythmia recurrence (HR 0.58, 95% C.I. 0.43-0.78, p &lt; 0.0001). Pacemaker implantation was necessary in seven patients (AV block n = 4, sinus node dysfunction n = 3) and one patient received an ICD for secondary prophylaxis. Sudden death occurred in three patients. The most common arrhythmias in patients with SVP &gt; 40 years are IART and AF. Arrhythmia recurrence following EPS or DCCV is frequent. Older age is an independent risk factor for arrhythmia recurrence.

Role of Endothelin-1 in Right Atrial Arrhythmogenesis in Rabbits with Monocrotaline-Induced Pulmonary Arterial Hypertension.

Atrial arrhythmias are considered prominent phenomena in pulmonary arterial hypertension (PAH) resulting from atrial electrical and structural remodeling. Endothelin (ET)-1 levels correlate with PAH severity and are associated with atrial remodeling and arrhythmia. In this study, hemodynamic measurement, western blot analysis, and histopathology were performed in the control and monocrotaline (MCT, 60 mg/kg)-induced PAH rabbits. Conventional microelectrodes were used to simultaneously record the electrical activity in the isolated sinoatrial node (SAN) and right atrium (RA) tissue preparations before and after ET-1 (10 nM) or BQ-485 (an ET-A receptor antagonist, 100 nM) perfusion. MCT-treated rabbits showed an increased relative wall thickness in the pulmonary arterioles, mean cell width, cross-sectional area of RV myocytes, and higher right ventricular systolic pressure, which were deemed to have PAH. Compared to the control, the spontaneous beating rate of SAN–RA preparations was faster in the MCT-induced PAH group, which can be slowed down by ET-1. MCT-induced PAH rabbits had a higher incidence of sinoatrial conduction blocks, and ET-1 can induce atrial premature beats or short runs of intra-atrial reentrant tachycardia. BQ 485 administration can mitigate ET-1-induced RA arrhythmogenesis in MCT-induced PAH. The RA specimens from MCT-induced PAH rabbits had a smaller connexin 43 and larger ROCK1 and phosphorylated Akt than the control, and similar PKG and Akt to the control. In conclusion, ET-1 acts as a trigger factor to interact with the arrhythmogenic substrate to initiate and maintain atrial arrhythmias in PAH. ET-1/ET-A receptor/ROCK signaling may be a target for therapeutic interventions to treat PAH-induced atrial arrhythmias.

The high-density grid catheter: A safe adjunctive tool in pediatric and complex congenital heart disease patients.

The safety and utility of the Advisor™ High-Density Grid mapping catheter (HDGC) in children and congenital heart disease (CHD) patients are not well described. A single-center retrospective cohort study of pediatric and CHD patients undergoing electrophysiology study and ablation to determine the effect of HDGC use on outcomes including complications, fluoroscopy use, procedure duration, acute ablation success, and arrhythmia recurrence. HDGC was used in 74/261 (28.3%) cases. HDGC subjects differed by median age (17 vs. 13 years; p < 0.001),weight (68 vs. 50 kg; p < 0.001), and prevalence of significant CHD (42% vs. 3%; p < 0.001). Arrhythmia substrates were dissimilar: HGDC cases had higher frequencies of intra-atrial re-entrant tachycardia (25.7% vs. 0.5%), atrial flutter (8.1% vs. 1.1%), ectopic atrial tachycardia (13.5% vs. 3.7%), and premature ventricular contractions (9.5% vs. 0.5%), and lower incidences of atrioventricular re-entrant tachycardia (16.2% vs. 46.1%). Complications were rare (n = 5, 1.9%) with no significant difference between groups (p = 1.00). Procedure duration-but not fluoroscopy exposure-was significantly longer in HDGC cases (median 256 vs. 216 min, p < 0.001). Acute success was lower (93.2% vs. 99.4%; p = 0.01) and recurrences higher (13.2% vs. 3.8%; p = 0.016) in HDGC compared to non-HDGC cases. HDGC use in children and CHD patients is safe and not associated with higher complication rates. The lower acute success and higher recurrence rates in HDGC cases likely reflect a bias toward HDGC use in more complex arrhythmia substrates rather than less favorable ablation outcomes.

Anesthetic Management in Parturients With Fontan Physiology

Anesthetic Management in Parturients With Fontan Physiology