Search

Introduction: The reduction of fluoroscopic exposure during catheter ablation of supraventricular arrhythmias is widely adopted by experienced electrophysiology physicians with a relatively short learning curve and is becoming the standard of care in many parts of the world. While observational studies in the United States and some parts of Western Europe have evaluated the minimal fluoroscopic approach, there are scarce real-world data for this technique and the generalizability of outcomes in other economic regions., Method: The AALARA study is a prospective, observational, multicenter, and multinational open-label study. Patients were recruited from 13 countries across Central Eastern Europe, North and South Africa, the Middle East, and the CIS (Commonwealth of Independent States), with different levels of operator expertise using minimal fluoroscopic exposure techniques. Data on radiation exposure, procedural success, complications, recurrence, and quality of life changes were collected and analyzed., Result: A total of 680 patients were enrolled and followed for 6 months. The majority were ablation naïve with the commonest arrhythmia ablated being typical AVNRT (58%) followed by Atrial Flutter (23%). Zero fluoroscopy exposure was observed in almost 90% of the cases. Fluoroscopy was most commonly used during the ablation phase of the procedure. We observed a high acute success rate (99%), a low complication rate (0.4%), and a 6-month recurrence rate of 3.8%. There was a significant improvement in the patient's symptoms and quality of life as measured by patient global assessment., Conclusion: The routine use of a 3D mapping system during right-sided ablation was associated with low radiation exposure and associated with high acute success rate, low complications, and recurrence rate along with significant improvement in quality of life. The data confirm the reproducibility of this approach in real-world settings across different healthcare systems, and operator experience supporting this approach to minimize radiation exposure without compromising efficacy and safety., Trial Registration: NCT04716270., (© 2024 The Author(s). Pacing and Clinical Electrophysiology published by Wiley Periodicals LLC.)

Introduction: The decremental properties of the nodoventricular pathway (NVP) are uncertain., Methods and Results: During short RP supraventricular tachycardia, a His-refractory premature ventricular contraction (PVC) consistently terminated the tachycardia without atrial capture immediately after the PVC. Whereas a slightly earlier PVC failed to reset the subsequent His but terminated the tachycardia without atrial capture one cycle later., Conclusion: These observations are diagnostic of slow-fast atrioventricular nodal reentrant tachycardia (AVNRT) with a bystander concealed-NVP and can be explained by decremental properties in the NVP itself; greater prematurity of the PVC resulted in more decremental conduction over the NVP, causing the AVNRT termination one cycle later., (© 2024 Wiley Periodicals LLC.)

Objective: Pregnancy can trigger maternal tachycardias, and the onset of recurrent or incessant focal atrial tachycardia (AT) can lead to tachycardia-induced cardiomyopathy. Medical interventions are commonly employed, but they carry potential fetal and maternal risks. Catheter ablation (CA), particularly with non-fluoroscopic navigation systems, may be considered as an alternative. This systematic review aims to explore the feasibility and outcomes of CA for focal AT during pregnancy., Methods: A thorough literature search was conducted until September 30th, 2023, on PubMed, Embase, and Cochrane databases. Included articles described maternal focal ATs diagnosed through electrophysiological studies and treated with CA. Data derived from these studies were organized into tables and subsequently analyzed., Results: Out of 278 papers reviewed, 15 articles involving 24 patients were retrieved. CA, utilizing radiofrequency energy achieved acute success in 95.8% of cases. Sixteen patients (66.7%) underwent complete fluoroless procedures, with two adverse events directly related to the procedure reported. Long-term follow-up revealed minimal AT recurrences, with a 0.06% arrhythmia burden in one case., Conclusion: Focal ATs during pregnancy can be incessant and refractory to medical intervention, precipitating an acute decline in left ventricular ejection fraction. In this setting, CA emerges as an efficacious treatment modality, particularly in cases of tachycardia-induced cardiomyopathies. Whenever feasible, it is advisable to perform these procedures with minimal or no fluoroscopy guidance. Larger studies are needed to establish the safety and the efficacy of CA for focal ATs during pregnancy, as current research consists of case reports or small case series., Competing Interests: Declaration of competing interest The authors have no conflict of interest to declare regarding this manuscript., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Pulsed-field ablation (PFA) is a novel nonthermal energy that shows unique features that can be of use beyond pulmonary vein ablation, like tissue selectivity or proximity rather than contact dependency., Methods and Results: We report three cases of right focal atrial tachycardias arising from the superior cavoatrial junction and the crista terminalis, in close relationship with the phrenic nerve, effectively ablated using a commercially available PFA catheter designed for pulmonary vein isolation without collateral damage., Conclusion: PFA can be useful for treating right atrial tachycardias involving sites near the phrenic nerve, avoiding the need for complex nerve-sparing strategies., (© 2024 Wiley Periodicals LLC.)

Background: The aorta-mitral annulus conjunction (AMC) is an uncommon site of origin of focal atrial tachycardias (ATs). Hence, the electrophysiological and ablation target characteristics are poorly described., Objective: The purpose of this study was to describe the characteristics of AMC ATs in detail., Methods: The study enrolled 650 patients with ATs, 21 (3.2%) of whom had ATs originating from the AMC. A comprehensive evaluation, including electrocardiography, electrophysiology study, computed tomography scan, and intracardiac echocardiography, was performed., Results: The majority (19, 90.5%) of ATs occurred spontaneously. The mean age of this group was 48.9 ± 21.6 years, with 12 being female (57.1%). Seventeen patients had a typical biphasic P wave with a prominent positive component. The earliest activation site in the right atrium was near the His bundle, with average activation -10.3 ± 6.0 ms preceding the P wave. The successful ablation targets were distributed as follows: 1 case at 9 o'clock, 6 cases at 10 o'clock, 7 cases at 11 o'clock, 6 cases at 12 o'clock, and 1 case in the left coronary cusp. The local AMC potential differed from the commonly perceived annular potential and was characterized by a prominent A wave and a smaller V wave (atrial-to-ventricular ratio > 1). The angle of encroachment on the left atrial anterior wall, compressed by the left coronary cusp, was significantly smaller in the AMC ATs group than in the control group consisted of 40 patients who underwent coronary artery CT scans because of the chest pain but without atrial arrhythmias were randomly selected, which may have contributed to the arrhythmia substrate (141.7° ± 11.5° vs 155.2° ± 13.9°; P = .026)., Conclusion: A new strategy for mapping AMC ATs has been introduced. The ablation target should have an atrial-to-ventricular ratio of >1., Competing Interests: Disclosures All authors report no disclosures., (Copyright © 2024. Published by Elsevier Inc.)

We present a case of a 45-year-old male with symptomatic supraventricular tachycardia. Electrophysiology study and 3-dimensional (3D) electroanatomic mapping showed a focal atrial tachycardia originating from a large left atrial diverticulum. Due to the unusual anatomy, 3D printing models were used to aid successful catheter ablation of the atrial tachycardia., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

Background: Patients may develop atrial tachycardia (AT) after left atrial (LA) ablation of persistent atrial fibrillation (AF)., Methods: The population consisted of 101 consecutive patients (age = 64.3 ± 8.7 years, 70 males (69%), LA = 4.6 ± 0.8 cm, ejection fraction = 48.5 ± 16%) undergoing their initial procedure for persistent AF. After pulmonary vein isolation, patients either underwent posterior LA isolation (n = 50; study group) or linear ablation at the LA roof with verification of conduction block (n = 51; control group)., Results: A repeat procedure was performed in 17 (34%) and 28 (55%) patients in the study and control groups, respectively (p = 0.02). Patients in the study group were less likely to develop AT (9/50 [18%] vs. 18/51 [35%]; p = 0.02), roof-dependent (1/50 [2%] vs. 8/51 [16%]; p = 0.008), and multi-loop AT (6/50 [12%] vs. 14/51 [27%]; p = 0.03) as compared to controls. Among various factors, only posterior LA isolation was associated with a lower likelihood of AT recurrence and roof tachycardia at redo procedure (OR, 0.37; 95% CI, 0.1 to 1.00, p = 0.05, and OR, 0.1, 95% CI, 0.01 to 0.96; p < 0.05, respectively)., Conclusions: In patients with persistent AF, posterior LA isolation is associated with a lower risk of a redo procedure, roof-dependent macro-reentry, and post-ablation AT in general as compared to controls who only received roof ablation. Posterior LA isolation also obviates the need for pacing maneuvers, and may be a more definitive endpoint than linear ablation at the LA roof., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: The impact of early recurrence of atrial tachyarrhythmia (ERAT) within the 90-day blanking period on long-term outcomes in atrial fibrillation (AF) patients undergoing cryoballoon ablation (CBA) is controversial. This study aimed to assess the relationship between ERAT and late recurrence of atrial tachyarrhythmia (LRAT) post-CBA., Methods: Utilizing data from a multicenter registry in Korea (May 2018 to June 2022), we analyzed the presence and timing of ERAT (<30, 30-60, and 60-90 days) and its association with LRAT risk after CBA. LRAT was defined as any recurrence of AF, atrial flutter, or atrial tachycardia lasting more than 30 s beyond the 90 days., Results: Out of 2636 patients, 745 (28.2%) experienced ERAT post-CBA. Over an average follow-up period of 21.2 ± 10.3 months, LRAT was observed in 874 (33.1%) patients. Patients with ERAT had significantly lower 1-year LRAT freedom compared to those without ERAT (42.6% vs. 85.5%, p < .001). Multivariate analysis identified ERAT as a potential predictor of LRAT, with a hazard ratio (HR) of 3.98 (95% confidence interval [CI], 3.47-4.57). Significant associations were noted across all examined time frames (HR, 3.84; 95% CI, 3.32-4.45 in <30 days, HR, 5.53; 95% CI, 4.13-7.42 in 30-60 days, and HR, 4.29; 95% CI, 3.12-5.89 in 60-90 days). This finding was consistently observed across all types of AF., Conclusion: ERAT during the 90-day blanking period strongly predicts LRAT in AF patients undergoing CBA, indicating a need to reconsider the clinical significance of this period., (© 2024 The Author(s). Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Introduction: There is a lack of studies in the literature directly investigating the relationship between atrial tachycardia (AT) and left atrial (LA)/left atrial appendage (LAA) thrombus, and current guidelines do not provide strong recommendations regarding the use of transesophageal echocardiography (TEE) before AT catheter ablation. This study aims to elucidate the relationship between AT and the presence of LA/LAA thrombus and contribute to the literature on the use of TEE before AT catheter ablation., Methods: This single-center retrospective observational study screened patients who underwent TEE between February 10, 2019, and February 10, 2023. Patients were assigned to the AT patient and control groups. TEE was conducted to exclude thrombus in the AT ablation group. The control group included patients who underwent TEE for interatrial septum evaluation and had LA imaging during TEE but did not have atrial arrhythmia. To mitigate bias between the AT patient group and the control group, they were randomized 1:1 using propensity-score matching (PSM). Following randomization, each group consisted of 49 patients., Results: All analyses were conducted after PSM. There were no statistically significant differences between the AT patient and control groups in terms of baseline clinical characteristics and echocardiographic features. Additionally, no significant differences were found between the blood viscosities calculated at low and high shear rates in both groups. The study revealed a significant difference between the two groups in the presence of LA spontaneous echo contrast (SEC) (24.5% in AT group vs 0% in Control group, p = .001), but not in the presence of thrombi (8.2% in AT group vs 0% in Control group, p = .117)., Conclusion: Compared to the control group, the presence of SEC was significantly higher in the AT patient group. The increased frequency of SEC in AT patients suggests the hypothesis that AT may contribute to LA stasis. The routine use of TEE before AT catheter ablation remains controversial, despite the presence of LA thrombus and SEC in the AT patient group. The clinical assessment of thrombus presence before the procedure must be conducted on a patient-specific basis., (© 2024 Wiley Periodicals LLC.)

Background: The relationship between induction and recurrence due to atrial tachycardia (AT) and left atrial (LA) matrix progression after atrial fibrillation (AF) ablation remains unclear., Methods: One hundred fifty-two consecutive patients with paroxysmal and persistent AF who underwent pulmonary vein isolation (PVI) and cavo-tricuspid isthmus (CTI) ablation and achieved sinus rhythm before the procedure were classified into three groups according to the AT pattern induced after the procedure: group N (non-induced), F (focal pattern), and M (macroreentrant pattern) in 3D mapping., Results: The total rate of AT induction was 19.7% (30/152) in groups F (n = 13) and M (n = 17). Patients in group M were older than those in groups N and F, with higher CHADS 2 /CHA 2 DS 2 -VASc values, left atrial enlargement, and low-voltage area (LVA) size of LA. The receiver operating characteristic curve determined that the cut-off LVA for macroreentrant AT induction was 8.8 cm 2 (area under the curve [AUC]: 0.86, 95% confidence interval [CI]: 0.75-0.97). The recurrence of AT at 36 months in group N was 4.1% (5/122), and at the second ablation, all patients had macroreentrant AT. Patients with AT recurrence in group N had a wide LVA at the first ablation, and the cut-off LVA for AT recurrence was 6.5 cm 2 (AUC 0.94, 95%CI 0.88-0.99). Adjusted multivariate analysis showed that only LVA size was associated with the recurrence of macroreentrant AT (odds ratio 1.21, 95%CI 1.04-1.51)., Conclusions: It is important to develop a therapeutic strategy based on the LVA size to suppress the recurrence of AT in these patients., (© 2024. The Author(s).)

Background: An accurate display of scar-related atrial tachycardia (ATs) is a key determinant of ablation success. The efficacy of ripple mapping (RM) in identifying the mechanism and critical isthmus of scar-related ATs during coherent mapping is unknown., Methods: A total of 97 patients with complex ATs who underwent radiofrequency catheter ablation at our center between October 2018 and September 2022 were included. ATs was mapped using a multielectrode mapping catheter on the CARTO3v7 CONFIDENCE module. Coherent and RM were used to identify the reentrant circuit., Results: The mechanisms of 128 ATs were analyzed retrospectively (84 anatomic-reentrant ATs and 44 non-anatomic reentrant ATs). The median AT cycle length was 264 ± 25ms. The correct diagnosis was achieved in 83 ATs (68%) using only coherent mapping. Through coherent mapping plus RM, 114 ATs (84.2%) were correctly diagnosed (68% vs. 89%, p = .019). In non-anatomical reentrant ATs, 81% of the diagnostic rate was achieved by reviewing both coherent and ripple mapping compared to reviewing coherent mapping alone (81% vs. 52%, p = .03). Reviewing coherent mapping and ripple mapping showed a higher diagnostic rate in patients who underwent cardiac surgery than those with Coherent mapping alone (64% vs. 88%, p = .04)., Conclusion: Coherent mapping combined with RM was superior to coherent mapping alone in identifying the mechanism of scar-related ATs post-cardiac surgery and non-anatomic reentrant ATs., (© 2024 Wiley Periodicals LLC.)

Introduction: The unique safety profile of pulsed field ablation (PFA) has made pulmonary vein isolation (PVI) + left atrial posterior wall (LAPW) ablation promising for treating persistent atrial fibrillation (PerAF). The goal of this study was to assess long-term freedom from atrial fibrillation, atrial flutter, and atrial tachycardia (AF/AFL/AT), as well as the safety and feasibility of LAPW PFA using multipolar, pentaspline Farawave catheter., Methods: Retrospective observational study at a single institution. Data for 94 patients were collected from a prespecified intraprocedural registry. The long-term AF/AFL/AT recurrence assessment was based on an analysis of medical history; 24-h Holter ECGs at 3, 6, and 12 months postablation; and 12-lead ECGs recorded during symptomatic episodes or visits., Results: Half of the patients had ls-PerAF, and half had a history of catheter ablation-mostly RF PVI. The acute ablation success rate was 100%, and the primary safety outcome was observed in 2 patients. Fifty patients experienced AF/AFL/AT recurrence (54.3%). An increase in LAPW low-voltage areas and AF classification were associated with arrhythmia recurrence. After a median follow-up of 13 months, the Kaplan‒Meier estimated median time free of AF/AFL/AT after a single procedure was 14.7 months., Conclusion: PFA PVI + PWA had the best outcome in perAF patients without extensive LA fibrosis. AF recurrence was paroxysmal in significant part of the cohort. The addition of PWA to PVI using multipolar PFA was safe and did not significantly influence the transpired ablation time., (© 2024 The Author(s). Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Introduction: Ablation of scar-related reentrant atrial tachycardia (SRRAT) involves identification and ablation of a critical isthmus. A graph convolutional network (GCN) is a machine learning structure that is well-suited to analyze the irregularly-structured data obtained in mapping procedures and may be used to identify potential isthmuses., Methods: Electroanatomic maps from 29 SRRATs were collected, and custom electrogram features assessing key tissue and wavefront properties were calculated for each point. Isthmuses were labeled off-line. Training data was used to determine the optimal GCN parameters and train the final model. Putative isthmus points were predicted in the training and test populations and grouped into proposed isthmus areas based on density and distance thresholds. The primary outcome was the distance between the centroids of the true and closest proposed isthmus areas., Results: A total of 193 821 points were collected. Thirty isthmuses were detected in 29 tachycardias among 25 patients (median age 65.0, 5 women). The median (IQR) distance between true and the closest proposed isthmus area centroids was 8.2 (3.5, 14.4) mm in the training and 7.3 (2.8, 16.1) mm in the test group. The mean overlap in areas, measured by the Dice coefficient, was 11.5 ± 3.2% in the training group and 13.9 ± 4.6% in the test group., Conclusion: A GCN can be trained to identify isthmus areas in SRRATs and may help identify critical ablation targets., (© 2024 Wiley Periodicals LLC.)

Background: Pulsed field ablation (PFA) is primarily used for treatment of atrial fibrillation as it provides better safety and efficacy. However, there are limited data available on the use of PFA for paroxysmal supraventricular tachycardia (PSVT). The study sought to describe the outcomes of PSVT ablation with a novel focal contact force (CF)-sensing PFA., Methods: In this first-in-human pilot study, a focal CF-sensing PFA catheter was used for mapping and ablation navigated with an electroanatomic mapping system (EAMS). Pulsed field energy was delivered as biphasic/bipolar electrical pulse trains with 2000 V/delivery. CF was controlled from 2 g to 10 g during PFA., Results: Procedural acute success was achieved without general anaesthesia or conscious sedation in all 10 patients, including 7 patients diagnosed with typical atrioventricular nodal re-entrant tachycardias and 3 patients with orthodromic reciprocating tachycardias. Successful target ablation time was 2.0 ± 0.5 seconds per patient, and the acute procedural success at the first single site was achieved in 5 patients. The mean skin-to-skin procedure time was 79.4 ± 15 minutes, PFA catheter dwell time was 50.1 ± 14 minutes, and fluoroscopy time was 6.2 ± 7 minutes. Maintenance of sinus rhythm was observed in all patients within 6-month follow-up. No serious adverse events occurred in any subjects during PFA or during the 6-month follow-up., Conclusions: A focal CF-sensing PFA catheter could effectively, rapidly, and safely ablate PSVT in conscious patients., Clinical Trial Registration: NCT05770921., (Copyright © 2024 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Aims: Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) is often accompanied by atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT), which are difficult to control because beta-blockers and antiarrhythmic drugs can worsen heart failure (HF). This study aimed to investigate the outcomes of catheter ablation (CA) for AF/AFL/AT in patients with ATTRwt-CM and propose a treatment strategy for CA., Methods and Results: A cohort study was conducted on 233 patients diagnosed with ATTRwt-CM, including 54 who underwent CA for AF/AFL/AT. The background of each arrhythmia and the details of the CA and its outcomes were investigated. The recurrence-free rate of AF/AFL/AT overall in ATTRwt-CM patients with multiple CA was 70.1% at 1-year, 57.6% at 2-year, and 44.0% at 5-year follow-up, but CA significantly reduced all-cause mortality [hazard ratio (HR): 0.342, 95% confidence interval (CI): 0.133-0.876, P = 0.025], cardiovascular mortality (HR: 0.378, 95% CI: 0.146-0.981, P = 0.045), and HF hospitalization (HR: 0.488, 95% CI: 0.269-0.889, P = 0.019) compared with those without CA. There was no recurrence of the cavotricuspid isthmus (CTI)-dependent AFL, non-CTI-dependent simple AFL terminated by one linear ablation, and focal AT originating from the atrioventricular (AV) annulus or crista terminalis eventually. Twelve of 13 patients with paroxysmal AF and 27 of 29 patients with persistent AF did not have recurrence as AF. However, all three patients with non-CTI-dependent complex AFL not terminated by a single linear ablation and 10 of 13 cases with focal AT or multiple focal ATs originating beyond the AV annulus or crista terminalis recurred even after multiple CA., Conclusion: The outcomes of CA for ATTRwt-CM were acceptable, except for multiple focal AT and complex AFL. Catheter ablation may be aggressively considered as a treatment strategy with the expectation of improving mortality and hospitalization for HF., Competing Interests: Conflict of interest: H.K. has received grants from Medtronic Japan, Nihon Kohden, Abbott Medical Japan, Fukuda Denshi, Boston Scientific Japan, Japan Lifeline, Nipro, and Biotronik Japan. K.T. has received honoraria from Bayer Yakuhin, Daiichi Sankyo, Kowa, MSD, Sanofi, and Takeda Pharmaceutical and grants from Astellas Pharma, Abbott Vascular Japan, Bayer Yakuhin, Boehringer Ingelheim Japan, Boston Scientific Japan, Bristol-Myers, Chugai Pharmaceutical, Daiichi Sankyo, Goodman, Japan Lifeline, Medtronic Japan, Mitsubishi Tanabe Pharma, MSD, Novartis Pharma, Otsuka Pharmaceutical, Sanofi, Takeda Pharmaceutical, and Terumo. All remaining authors have declared no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

The left atrial appendage (LAA) is now recognized as a significant contributor to arrhythmia and thromboembolism in patients with a history of atrial fibrillation. Thoracoscopic exclusion of the LAA is made possible with the AtriClip device. In this report, we describe the case of a 65-year-old man with history of multiple left atrial ablation procedures and LAA clipping. He developed a microreentrant atrial tachycardia originating from the anterior base of the LAA stump, underwent complete isolation of the LAA, and had subsequent resolution of arrhythmogenic activity from the residual LAA stump., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2023 Elsevier Inc. All rights reserved.)

A case of successful catheter ablation of paroxysmal atrial fibrillation and atrial tachycardia is reported. After pulmonary vein isolation, atrial tachycardia was induced by the use of isoproterenol and burst pacing from the catheter in the right atrium. An attempt was made to create a three-dimensional (3D) map of the atrial tachycardia, but the atrial tachycardia was terminated in the middle of the mapping. The 3D map was insufficient but indicated that the superior vena cava was involved in the circuit. When the intracardiac electrograms were reviewed, it was found that the atrial tachycardia was initiated with orthodromic capture of superior vena cava potentials and it was considered that the atrial tachycardia involved the superior vena cava-right atrium junction. Accordingly, superior vena cava isolation was performed. After that, atrial fibrillation and atrial tachycardias were not induced by the use of isoproterenol and burst pacing. In this case, an intracardiac electrogram at the time of induction of the tachycardia was helpful for understanding the circuit of the tachycardia., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

A 34-year-old woman presented with palpitations and paroxysmal atrial fibrillation (AF). Workup revealed anterior mitral valve prolapse with severe mitral regurgitation. She was referred for surgical repair and underwent a mitral valve replacement, tricuspid valve repair, and bi-atrial cryoMAZE procedure with left atrial appendage ligation. Her postoperative course was complicated by inferior wall myocardial infarction. She subsequently presented with palpitations and underwent electrophysiology study and ablation. This case illustrates pitfalls associated with the surgical MAZE procedure and highlights the challenges in postoperative atrial arrhythmias diagnosis and management., Competing Interests: Disclosures No disclosures to report., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background and Aims: Trends in patient selection and use of pharmacotherapy prior to catheter ablation (CA) for supraventricular tachycardia (SVT) are not well described. This study examined temporal trends in patients undergoing first-time CA for regular SVT, including atrioventricular nodal re-entry tachycardia (AVNRT), accessory pathways (APs), and ectopic atrial tachycardia (EAT) on a nationwide scale in Denmark in the period 2001-2018., Methods and Results: Using Danish Nationwide registers, 9959 patients treated with first-time CA for SVT between 2001 and 2018 were identified, of which 6023 (61%) received CA for AVNRT, 2829 (28%) for AP, and 1107 (11%) for EAT. Median age was 55, 42, and 55 in the AVNRT, APs, and EAT group, respectively. The number of patients receiving CA increased from 1195 between 2001 and 2003 to 1914 between 2016 and 2018. The percentage of patients with a CHA 2 DS 2 -VASc score ≥ 2 increased in all patient groups. The number of patients who underwent CA with no prior use of antiarrhythmic- or rate limiting medicine increased significantly, though prior use of beta-blockers increased for AVNRT patients. Use of verapamil decreased in all three SVT groups (P < 0.05). Use of amiodarone and class 1C antiarrhythmics remained low, with the highest usage among EAT patients., Conclusion: Between 2001 and 2018, CA was increasingly performed in patients with SVT, primarily AVNRT- and EAT patients. The burden of comorbidities increased. Patients undergoing CA without prior antiarrhythmic- or rate-limiting drug therapy increased significantly. Use of beta-blockers increased and remained the most widely used drug., (© 2023. The Author(s).)

Introduction: Left atrial (LA) low voltage areas (LVA) are a controversial target in atrial fibrillation ablation procedures. However, LVA and LA volume are good predictors of arrhythmia recurrence in ablation-naïve patients. Their predictive value in progressively diseased pre-ablated atria is uncertain., Methods: Consecutive patients with recurrent atrial fibrillation (AF) or atrial tachycardia (AT), who were scheduled for repeat LA ablation, were enrolled in the prospective Bernau ablation registry between 2016 and 2020. All patients received a complete LA ultrahigh-density map before ablation. Maps were analyzed for LA size, LVA percentage and distribution. The predictive value of demographic, anatomic, and mapping variables on AF recurrence was analyzed., Results: 160 patients (50.6% male, 1.3 pre-ablations, 60% persistent AF) with complete LA voltage maps were included. Mean follow-up time was 16 ± 11 months. Mean recorded electrograms (EGMs) per map were 9754 ± 5808, mean LA volume was 176.1 ± 35.9 ml and mean rate of LVAs <0.5 mV was 30.6% ± 23.1%. During follow-up recurrence rate of AF or AT >30 s was 55.6%. Patients with recurrence had a significant higher percentage of LVAs (40.0% vs. 18.8%, p < .001) but no relevant difference in LA volume (172 vs. 178 mL, p = .299). ROC curves revealed LVA as a good predictor for recurrence (AUC = 0.79, p < .001) and a cut-off of 22% LVAs with highest sensitivity (73.0%) and specificity (71.8%). Based on this cut off, event free survival was significantly higher in the Low LVA group (p < .01)., Conclusion: Total LVA percentage has a good predictive power on arrhythmia recurrence in a cohort of advanced scarred left atria in repeat procedures independent of the applied ablation strategy. Left atrial volume seems to have minor impact on the rhythm outcome in our study cohort., (© 2024 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Background: Few data are available regarding temporal patterns of health resource utilization (HRU) and expenditures among patients undergoing catheter ablation for paroxysmal supraventricular tachycardia (PSVT). This study aimed to describe expenditures and HRU in patients with PSVT who underwent catheter ablation compared to a matched cohort of patients on medical therapy alone., Methods: Using a large US administrative database, we identified adult patients (age 18 to 65 years) with a new PSVT diagnosis between 2008 and 2016. Propensity-score matching was used to assemble a PSVT cohort treated with ablation or medical therapy alone (N = 2556). Longitudinal trends in HRU and expenditures in the 3-years preceding and following PSVT diagnosis were compared., Results: There were no significant differences in expenditures between groups except within the first year after PSVT diagnosis: $48,004 ablation vs. $17,560 medical therapy (p < 0.001). This difference was driven by procedural expenditures, where the mean cost of catheter ablation was $32,057 ± SD 26,737. In Years 2 and 3 post-ablation, HRU and expenditures decreased to the levels associated with the medical therapy group, although fewer ablation patients required any prescription for beta-blockers, calcium channel blockers, or anti-arrhythmic drugs (32% ablation vs. 42% medical therapy group, p < 0.001)., Conclusion: Catheter ablation reduces medication burden in PSVT, yet health resource use and expenditures were similar beyond 2 years post-ablation when compared to PSVT patients on medical therapy alone. Additional studies are required to better understand drivers of these sustained health expenditures, and barriers to achieving cost-savings for a potentially curative procedure., Competing Interests: Declaration of competing interest DC reports research grant support from the Heart and Stroke Foundation of Canada and the Canadian Institutes of Health Research. SDP reports research grant support from Boston Scientific, Bristol-Myers Squibb, Pfizer, Janssen Pharmaceuticals, Gilead; and advisory board/speakers honoraria from Boston Scientific, Medtronic, Bristol-Myers Squibb, Pfizer, Janssen Pharmaceuticals, and Zoll. RS is employed by Milestone Pharmaceuticals. The remaining authors have no conflicts of interest to disclose., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Aims: To evaluate the effect of electro-anatomical mapping on success rate and fluoroscopy time in ablation of supraventricular tachycardia substrates in a large group of children., Methods: Patients referred from multiple centres in the Netherlands and who received a first ablation for supraventricular tachycardia substrates in the Leiden University Medical Center between 2014 and 2020 were included in this retrospective cohort study. They were divided in procedures in patients with fluoroscopy and procedures in patients using electro-anatomical mapping., Results: Outcomes of ablation of 373 electro-anatomical substrates were analysed. Acute success rate in the fluoro-group (n = 170) was 95.9% compared to 94.5% in the electro-anatomical mapping group (n = 181) (p = 0.539); recurrence rate was 6.1% in the fluoro-group and 6.4% in the electro-anatomical mapping group (p = 0.911) after a 12-months follow-up. Redo-ablations were performed in 12 cases in the fluoro-group and 10 cases in the electro-anatomical mapping group, with a success rate of 83.3% versus 80.0%, resulting in an overall success rate of 95.9% in the fluoro-group and 92.8% in the electro-anatomical mapping group (p = 0.216) after 12 months. Fluoroscopy time and dose area product decreased significantly from 16.00 ± 17.75 minutes (median ± interquartile range) to 2.00 ± 3.00 minutes (p = 0.000) and 210.5 µGym 2 ± 249.3 to 32.9 µGym 2 ± 78.6 (p = 0.000), respectively. In the fluoro-group, four complications occurred (2.0%) and in the electro-anatomical mapping group no complications occurred., Conclusion: These results demonstrate that ablations of supraventricular tachycardia substrates in children remain a highly effective and safe treatment after the introduction of electro-anatomical mapping as a standard of care, while significantly reducing fluoroscopy time and dose area product.

A 62-year-old man with a history of catheter ablation for atrial fibrillation and atrial tachycardia (AT) received a line of block of the mitral isthmus (MI) and electrical isolation of the left atrial appendage (LAA). Upon entrainment pacing, AT recurred and was diagnosed as peri-mitral AT (PMAT) with electrical irrelevance of MI, LAA, and left pulmonary vein, having a critical isthmus identified as Marshall bundle (MB). MB was then infused with ethanol, leading to the successful treatment of the PMAT., (© 2023 Wiley Periodicals LLC.)

Atrial tachycardia (AT) is a common rhythm disorder, especially in patients with atrial structural abnormalities. Although voltage mapping can provide a general picture of structural alterations which are mainly secondary to prior ablations, surgery or pressure/volume overload, data is scarce regarding the functional characteristics of low voltage regions in the atrium to predict critical isthmus of ATs. Recently, functional substrate mapping (FSM) emerged as a potential tool to evaluate the functionality of structurally altered regions in the atrium to predict critical sites of reentry. Current evidence suggested a clear association between deceleration zones of isochronal late activation mapping (ILAM) during sinus/paced rhythm and critical isthmus of reentry in patients with left AT. Therefore, these areas seem to be potential ablation targets even not detected during AT. Furthermore, abnormal conduction detected by ILAM may also have a role to identify the potential substrate and predict atrial fibrillation outcome after pulmonary vein isolation. Despite these promising findings, the utility of such an approach needs to be evaluated in large-scale comparative studies. In this review, we aimed to share our experience and review the current literature regarding the use of FSM during sinus/paced rhythm in the prediction of re-entrant ATs and discuss future implications and potential use in patients with atrial low-voltage areas., (© 2024 The Authors. Pacing and Clinical Electrophysiology published by Wiley Periodicals LLC.)

Every year, 80,000-100,000 ablation procedures take place in the United States and approximately 1% of these involve paediatric patients. As the paediatric population undergoing catheter ablation to treat dysrhythmia is constantly growing, involvement of anaesthesiologists in the cardiac electrophysiology laboratory is simultaneously increasing. Compared with the adult population, paediatric patients need deeper sedation or general anaesthesia (GA) to guarantee motionlessness and preserve comfort. As a result, the anaesthesiologist working in this setting should keep in mind heart physiopathology as well as possible interactions between anaesthetic drugs and arrhythmia. In fact, drug-induced suppression of accessory pathways (APs) conduction capacity is a major concern for completing a successful electrophysiology study (EPS). Nevertheless, the literature on this topic is scarce and the optimal type of anaesthesia in EPS and ablation procedures in children is still controversial. Thus, the main goal of the present review is to collect the literature published so far on the effects on cardiac conduction tissue of the drugs commonly employed for sedation/GA in the cath lab for EPS and ablation procedures to treat supraventricular tachycardia in patients aged <18 years., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

In activation mapping of reentrant atrial tachycardia (AT), there was no reference for window of interest (WOI). We examined the timing of a successful termination site from end of the P wave and attempted to determine whether the critical isthmus can be identified using activation mapping when WOI was set as end to end of the P wave. Forty patients with 54 reentrant AT who underwent 3D electroanatomic mapping and radiofrequency catheter ablation were evaluated retrospectively. The critical isthmus was defined as a successful termination site. We evaluate critical isthmus timing from end of the P wave and percentage of critical isthmus timing from end of the P wave to tachycardia cycle length. In 54 reentrant AT, Macro-reentry was identified in 46 (85.2%) and micro-reentry was identified in eight (14.8%). The timing of the critical isthmus site from end of the P wave was - 4.0 ± 31.1 ms (Macro-reentry vs. Micro-reentry; - 8.9 ± 29.4 ms vs. 24.0 ± 26.7 ms; P = 0.005). The percentage of critical isthmus timing from end of the P wave/tachycardia cycle length was - 1.4 ± 10.5% (Macro-reentry vs. Micro-reentry; - 3.1 ± 9.8% vs. 8.3 ± 9.3%, P = 0.004) The critical isthmus of reentrant AT is located within 10% backward and forward from end of the P wave to tachycardia cycle length. Setting the WOI from end to end of the P wave is useful for identification of the critical isthmus through activation mapping., (© 2023. Springer Nature Japan KK, part of Springer Nature.)

In symptomatic children without documented supraventricular tachycardia (SVT) and non-inducible atrioventricular nodal reentry tachycardia (AVNRT) the benefit of empiric slow pathway (SP) ablation is unknown. We evaluated 62 symptomatic patients without documented SVT that underwent electrophysiology study (EPS). The purpose of this study was to determine if symptoms improved after empiric SP ablation in children without documented SVT and without inducible AVNRT. Sixty-two symptomatic patients without previously documented SVT underwent EPS; 31 (50%) had inducible AVNRT and underwent SP ablation, 20 (32%) were non-inducible and underwent empiric SP ablation, 11 (18%) were non-inducible and had no ablation. After a mean follow-up of 23 ± 18 months there was no significant difference in freedom from symptoms within the non-inducible cohort regardless of whether empiric SP ablation was performed (p = 0.135). There was a significant improvement in symptoms at follow-up after SP ablation when comparing inducible and non-inducible patients (p = 0.020). During follow-up no patients had documented SVT. Symptomatic children without documented SVT do not benefit from empiric SP ablation when AVNRT cannot be induced., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

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.

Background: Drugs used for sedation/analgesia may affect the basic cardiac electrophysiologic properties or even supraventricular tachycardia (SVT) inducibility. Dexmedetomidine (DEX) is a selective alpha-2 adrenergic agonist with sedative and analgesic properties. A comprehensive evaluation on use of DEX for reentrant SVT ablation in adults is lacking. The present study aims to systematically assess the impact of DEX on cardiac electrophysiology and SVT inducibility., Methods: Hemodynamic, electrocardiographic, and electrophysiological parameters and SVT inducibility were assessed before and after DEX infusion in patients scheduled for ablation of reentrant SVT., Results: The population of this prospective observational study included 55 patients (mean age of 58.7 ± 14 years, 29 males [52.7%]). A decrease in systolic and diastolic blood pressure and in heart rate was observed after DEX infusion (p = 0.001 for all). DEX increased corrected sinus node refractory time, atrial effective refractory period, AH interval, AV Wenckebach cycle length, and AV node effective refractory period without affecting the His-Purkinje conduction or ventricular myocardium refractoriness. No AV blocks or sinus arrests occurred during DEX infusion. Globally, there was no difference in SVT inducibility in basal condition or after DEX infusion (46/55 [83.6%] vs. 43/55 [78.1%] patients; p = 0.55), without a difference in isoprenaline use (p = 1.0). In 4 (7.3%) cases, the SVT was inducible only after DEX infusion. In 34.5% of cases, DEX infusion unmasked the presence of an obstructive sleeping respiratory pattern, represented mainly by snoring., Conclusions: DEX depresses sinus node function and prolongs atrioventricular refractoriness without significantly affecting the rate of SVT inducibility in patients scheduled for reentrant SVT ablation., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In 1930, Wolff, Parkinson and White described the syndrome that bears their names. The mechanisms of supraventricular tachycardias were analyzed by brilliant electrocardiography interpretation by Pick and Langendorf. Wellens and Durrer using electrophysiologic studies analyzed the tachycardia mechanism invasively. In Germany the group by Seipel and Breithardt as well as Neuss and Schlepper studied the tachycardia mechanisms and response to antiarrhythmic drugs invasively by electrophysiological studies. Following the first successful interruption of an accessory pathway by Sealy in 1967, surgeons and electrophysiologists cooperated in Germany. Two centers, Hannover and Düsseldorf were established. Direct current (DC) ablation of accessory pathways was introduced by Morady and Scheinman. Because of side effects induced by barotrauma of DC, alternative strategies were studied. In 1987, radiofrequency ablation was introduced and thereafter established as curative therapy of accessory pathways in all locations., (© 2024. The Author(s).)

The development and clinical implementation of catheter ablation of supraventricular tachycardia is one of the outstanding achievements of modern cardiovascular treatment. Over a period of less than 40 years, a curative and safe treatment strategy for almost all forms of atrial arrhythmias has been developed and implemented. German electrophysiologists and engineers have made a significant contribution to this truly outstanding success story in modern medicine. Their contributions should be appropriately acknowledged because without them, the development of ablation technology and its worldwide dissemination would not have been possible. Both the technological contributions and the medical-electrophysiological contributions were at the absolute forefront of worldwide developments and have made a significant contribution to the fact that today more than 500,000 patients with symptomatic and/or threatening cardiac arrhythmias can be successfully treated every year by use of catheter ablation. We would like to thank them all for their achievements., (© 2024. The Author(s).)

Background: Pulsed field ablation (PFA) is a novel method of cardiac ablation where there is insufficient knowledge on the durability and reconnection patterns after pulmonary vein isolation (PVI). The aim of this study was to characterize the electrophysiological findings at time of repeat procedure in real-world atrial fibrillation (AF) patients., Methods: Patients who underwent a repeat procedure (n=26) for symptomatic recurrent arrhythmias after index first-time treatment with single-shot PFA PVI (n=266) from July 2021 to June 2023 were investigated with 3D high-density mapping and ad-hoc re-ablation by radiofrequency or focal PFA., Results: Index indication for PVI was persistent AF in 17 (65%) patients. The mean time to repeat procedure was 292 ± 119 days. Of the 26 patients (104 veins), complete durable PVI was observed in 11/26 (42%) with a durable vein isolation rate of 72/104 (69%). Two patients (8%) had all four veins reconnected. The posterior wall was durably isolated in 4/5 (80%) of the cases. The predominant arrhythmia mechanism was AF in 17/26 (65%) patients and regular atrial tachycardia (AT) in 9/26 (35%). Reconnection was observed 9/26 (35%) in right superior, 11/26 (42%) in right inferior, 7/26 (27%) in left superior, 5/26 (19%) in left inferior, p=0.31 between veins. The gaps were significantly clustered in the right-sided anterior carina compared to other regions (P=0.009)., Conclusions: Durable PVI was observed in less than half of the patients at time of repeat procedure. No significant difference in PV reconnection pattern was observed, but the gap location was preferentially located at the anterior aspects of the right-sided PVs. Predominant recurrence was AF. More data is needed to establish lesion formation and durability and AT circuits after PFA., (© 2023. The Author(s).)

Background: Radiofrequency catheter ablation (RFCA) may lead to decreased quality of life (QOL) and increased anxiety and depression in patients with paroxysmal supraventricular tachycardia (PSVT), possibly due to the lack of selectivity of the ablation tissue and the long ablation time. In recent years, pulsed field ablation (PFA) has been used for the first time in China to treat PSVT patients because of its ability to ablate abnormal tissue sites in a precise and transient manner. This study was conducted to compare the effects of PFA and RFCA on QOL and psychological symptoms of PSVT patients., Methods: We have designed a single-center, randomized, single-blind, standard-controlled trial. A total of 50 participants who met the eligibility criteria would be randomly allocated into the PFA group or RFCA group in a 1:1 ratio. All participants were assessed using the 36-Item Short-Form Health Survey (SF-36) and the Hospital Anxiety and Depression Scale (HADS) at pre-procedure (T0), post-procedure (T1), and 3 months post-procedure (T2). The SPSS 21.0 software was used to analyze the data through Wilcoxon and Fisher's exact tests and repeated measures ANOVA., Results: Twenty-five in the PFA group and 24 in the RFCA group completed the trial. SF-36: (1) Between-group comparison: At T1, PFA group had significantly higher SF-36 scores on physiological function (PF) and general health (GH) than RFCA group, with a treatment difference of 5.61 points and 18.51 points(P < 0.05). (2) Within-group comparison: We found that in the PFA and RFCA groups, T2 showed significant improvement in the remaining 6 subscales of the SF-36 scale compared to T1 and T0 (P < 0.05), except for body pain (BP) and social function (SF) scores. HADS: (1) Between-group comparison: no significant difference (P > 0.05). (2) Within-group comparison: The HADS scores of the PFA and RFCA groups were statistically significant at T2 compared to T0 and T1 (P < 0.05)., Conclusions: Our study provided new and meaningful evidence that PFA was effective in significantly improving QOL and decreasing anxiety and depression in PFA patients., Trial Registration: Chinese Clinical Trial Registry, ChiCTR2200060272., (© 2024. The Author(s).)

A one-year-and-seven-month-old, 28 kg, male castrated crossbreed dog was presented for supraventricular tachycardia causing recurrent episodes of anorexia and lethargy. Sotalol (2.2 mg/kg q12 h) reduced the frequency of symptomatic episodes but did not provide full relief. Three-dimensional electroanatomical mapping was performed at the Ghent University Small Animal Teaching hospital using the CARTO 3. Right atrial activation mapping identified the earliest atrial activation right posteroseptal, near the tricuspid annulus. Fast retrograde ventriculoatrial conduction during tachycardia and extrastimulus testing confirmed the presence of a concealed right posteroseptal accessory pathway. Six radiofrequency catheter ablation applications were delivered, and tachycardia remained uninducible. The dog recovered well from the procedure. Sotalol was stopped three weeks later, and no more clinical signs were noted by the owner. Repeated 24-hour electrocardiography monitoring on day one and at one, three, and 12 months after the procedure showed no recurrence of tachycardia., Competing Interests: Conflict of Interest Statement None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Aims: Data on the hybrid atrial fibrillation (AF) treatment are lacking in patients with structural heart disease undergoing concomitant CryoMaze procedures. The aim was to assess whether the timely pre-emptive catheter ablation would achieve higher freedom from AF or atrial tachycardia (AT) and be associated with better clinical outcomes than surgical ablation alone., Methods and Results: The trial investigated patients with non-paroxysmal AF undergoing coronary artery bypass grafting and/or valve repair/replacement with mandatory concomitant CryoMaze procedure who were randomly assigned to undergo either radiofrequency catheter ablation [Hybrid Group (HG)] or no further treatment (Surgery Group). The primary efficacy endpoint was the first recurrence of AF/AT without class I or III antiarrhythmic drugs as assessed by implantable cardiac monitors. The primary clinical endpoint was a composite of hospitalization for arrhythmia recurrence, worsening of heart failure, cardioembolic event, or major bleeding. We analysed 113 and 116 patients in the Hybrid and Surgery Groups, respectively, with a median follow-up of 715 (IQR: 528-1072) days. The primary efficacy endpoint was significantly reduced in the HG [41.1% vs. 67.4%, hazard ratio (HR) = 0.38, 95% confidence interval (CI): 0.26-0.57, P < 0.001] as well as the primary clinical endpoint (19.9% vs. 40.1%, HR = 0.51, 95% CI: 0.29-0.86, P = 0.012). The trial groups did not differ in all-cause mortality (10.6% vs. 8.6%, HR = 1.17, 95%CI: 0.51-2.71, P = 0.71). The major complications of catheter ablation were infrequent (1.9%)., Conclusion: Pre-emptively performed catheter ablation after the CryoMaze procedure was safe and associated with higher freedom from AF/AT and improved clinical outcomes., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: It would be helpful in determining ablation strategy if the occurrence of perimitral atrial tachycardia (PMAT) could be predicted in advance. We investigated whether estimated perimitral conduction time (E-PMCT), namely, twice the time between coronary sinus (CS) pacing and the ensuing wave-front collision at the opposite side of the mitral annulus, correlated with the cycle length of PMAT and could predict future PMAT., Methods and Results: We retrospectively (retrospective cohort) and prospectively (validation cohort) investigated atrial fibrillation patients who had received pulmonary vein isolation (PVI) and in whom left atrial maps had been created during CS pacing. We calculated their E-PMCT. PMAT was observed either by provocation or during follow-up in 25, AT other than PMAT was observed in 24 (non-PMAT AT group), and 53 patients never displayed any AT (no-AT group) in the retrospective cohort. In the PMAT group of the retrospective cohort, a strong positive correlation was observed between the PMAT CL and E-PMCT (r = .85, p < 0.001). PMAT was never induced nor observed in patients with E-PMCT less than 176 ms, and the best cut-off value for PMAT was 180 ms by receiver-operating characteristic curve analysis. In the validation cohort of 76 patients, the cut-off value of the E-PMAT less than 180 ms predicted noninducibility of PMAT, with a sensitivity of 78.6%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 25.0%., Conclusion: Short E-PMCT may predict noninducibility of PMAT and guide a less invasive ablation strategy., (© 2024 Wiley Periodicals LLC.)

Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Even with the development of advanced catheter-based mapping systems, there remain several challenges in the electrophysiological evaluation and elimination of atrial arrhythmias. For instance, atrial tachycardias with irregular rates cannot be reliably mapped by systems that require stability in order to sequentially gather data points to be organized thereafter. Separately, these arrhythmias often arise following initial ablation for atrial fibrillation, posing logistic challenges. Here, we present the available literature summarizing the use of a non-contact mapping catheter, the AcQMap catheter, in conjunction with SuperMap, an algorithm that compiles a large number of non-contact data points from multiple catheter positions within the atria. These studies demonstrate the efficiency, safety and accuracy of this technology.

Background: In arrhythmogenic right ventricular cardiomyopathy (ARVC), risk of atrial arrhythmias (AAs) persists after ventricular tachycardia (VT) ablation., Objective: The purpose of this study was to determine the type, prevalence, outcome, and risk correlates of AA in ARVC in patients undergoing VT ablation., Methods: Prospectively collected procedural and clinical data on ARVC patients undergoing VT ablation were analyzed. Risk score for typical atrial flutter was determined from univariate logistic regression analysis., Results: Of 119 consecutive patients with ARVC and VT ablation, 40 (34%) had AA: atrial fibrillation (AF) in 31, typical isthmus-dependent atrial flutter (AFL) in 27, and atrial tachycardia/atypical flutter (AT) in 10. Seventeen patients (43%) with AA experienced inappropriate defibrillator therapy, with 15 patients experiencing shocks. Ablation was performed for typical AFL in 21 (53%), AT in 5 (13%), and pulmonary vein isolation for AF in 4 (10%) patients and prevented AA in 78% and all AFL during additional mean follow-up of 65 months. Risk score for typical flutter included age >40 years (1 point), ≥moderate right ventricular dysfunction (2 points), ≥moderate tricuspid regurgitation (2 points), ≥moderate right atrial dilation (2 points), and right ventricular volume >250 cc (3points), with score >4 identifying 50% prevalence of typical flutter., Conclusion: AAs are common in patients with ARVC and VT, can result in inappropriate implantable cardioverter-defibrillator shocks, and typically are controlled with atrial ablation. A risk score can be used to identify patients at high risk for typical AFL who may be considered for isthmus ablation at the time of VT ablation., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

A previous study reported primary macroreentrant atrial tachycardia (AT) in the left atrium (LA), including the epicardial circuit on a left atrial anterior wall (LAAW) scar, without any prior cardiac intervention (Miyazawa et al. in J Cardiovasc Electrophysiol 2019; 30: 263-264). However, determining the target for terminating macroreentrant ATs is challenging. The mapping revealed a centrifugal pattern but did not fully elucidate the AT circuit. The reentrant mechanism of these ATs was confirmed using entrainment pacing. The earliest excitation site (EES) was traditionally selected as the ablation site, typically located in healthy tissue. However, our two cases provide new insights into AT termination, including the epicardial bridge across the endocardial LAAW scar, using minimum ablation points, without the need to ablate the healthy EES., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Supraventricular tachycardia (SVT) is a frequent complication of pulmonary hypertension (PH). The most prevalent SVTs are atrial fibrillation (AF) and typical atrial flutter (AFL), followed by focal and macroreentrant atrial tachycardia (AT) and nodal arrhythmia (AV nodal reentry tachycardia or AV reentry tachycardia). SVT is frequently associated with functional deterioration and right ventricular failure in PH patients. According to some data, reestablishing sinus rhythm is associated with clinical improvement. Catheter ablation of typical AFL, nodal tachyarrhythmias, or other less complex focal ATs have been shown to be feasible, acutely effective, and safe in patients with PH. However, the long-term clinical outcome is modified by the recurrence of index arrhythmia and the onset of a new SVT. Due to right atrial dilatation, technical issues can arise when ablation is carried out. The role of catheter ablation in patients with AF or more complex AT is even less effective. The results mirror the success rate in the general AF population with non-paroxysmal AF. However, the data is limited, and electrophysiological procedures are also more often complicated by specific adverse events in a severely frail population. Despite these limitations, catheter ablation is the treatment of choice in less complex SVT, but the indications for AF ablation must be more individualized.

Background: The past decades have seen the rapid development of the invasive treatment of arrhythmias by catheter ablation procedures. Despite its safety and efficacy being well-established in adults, to date there has been little data in pediatric scenarios. One of the main concerns is the possible expansion of the ablation procedure scar in this population and its consequences over the years., Objectives: This study aimed to analyze the risk of myocardial injury progression after radiofrequency catheter ablation in pediatric patients., Methods: This is a retrospective study of 20 pediatric patients with previous ablation for treatment of supraventricular arrhythmia that underwent cardiac magnetic resonance and coronary angiography for evaluation of myocardial fibrosis and the integrity of the coronary arteries during follow-up., Results: The median age at ablation procedure was 15.1 years (Q1 12.9, Q3 16.6) and 21 years (Q1 20, Q3 23) when the cardiac magnetic resonance was performed. Fourteen of them were women. Nodal reentry tachycardia and Wolf-Parkinson-White Syndrome were the main diagnosis (19 patients), with one patient with atrial tachycardia. Three patients had ventricular myocardial fibrosis, but with a volume < 0.6 cm 3 . None of them developed ventricular dysfunction and no patient had coronary lesions on angiography., Conclusion: Radiofrequency catheter ablation did not show to increase the risk of myocardial injury progression or coronary artery lesions.

Background: Activation mapping is often used to differentiate focal from re-entrant arrhythmias. This can be challenging but is critical to ablation success. The local activation time (LAT) histogram, which depicts point distribution over isochronal segments, may help characterize arrhythmia mechanisms and identify an optimal ablation strategy., Objectives: This study aimed to investigate features of the LAT histogram associated with the focal vs re-entrant mechanism of atrial tachycardias (ATs) and the use of the LAT histogram in the identification of target ablation sites., Methods: We retrospectively evaluated cases of focal and re-entrant ATs performed at a single academic tertiary care center for which activation mapping was performed using CARTO 3 version 7 software (Biosense Webster). Baseline patient, arrhythmia, and procedural characteristics as well as LAT histogram features were evaluated for each case. LAT histogram-guided ablation targets were also compared against actual ablation sites., Results: Among 52 ATs assessed, 17 were focal, and 35 were re-entrant. Tachycardia cycle length was significantly shorter in re-entrant than in focal ATs (288.2 milliseconds [Q1-Q3: 250-306.5 milliseconds] vs 370 milliseconds [Q1-Q3: 285-400 milliseconds], respectively; P = 0.006). LAT histograms contained more "valleys" in re-entrant than in focal ATs (3 [Q1-Q3: 2-4] vs 1 [Q1-Q3: 1-1]; P < 0.001). No focal ATs contained >2 and no re-entrant ATs contained <1 LAT valley(s). All successful ablation sites correlated with LAT histogram-suggested sites., Conclusions: LAT histograms can help distinguish focal from re-entrant Ats and identify effective ablation sites., Competing Interests: Funding Support and Author Disclosures Dr Maher has received consulting honoraria from Biosense Webster. Dr d’Avila has received research funding Biosense Webster. Ms Galvao is a clinical account specialist for Biosense Webster. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background and Aims: Ablation of anteroseptal accessory pathways (AS-AP) is challenging, with lower success and more complications compared to other APs. AS-APs can be successfully ablated from the right atrium (RA) or the aortic valve's noncoronary cusp (NCC). We report two patients who required a hybrid ablation approach to achieve successful abolition of both anterograde and retrograde AS-AP conduction., Methods and Results: A 21-year-old female with supraventricular tachycardia (SVT) and pre-excitation on electrocardiogram (ECG) underwent electrophysiology study (EPS) confirming an AS-AP with anterograde and retrograde conduction. Ablation in the NCC achieved immediate and persistent anterograde conduction block. Electrophysiological maneuvers showed persistent retrograde AP conduction and orthodromic reciprocating tachycardia (ORT) remained easily inducible. Additional ablation in the NCC did not eliminate retrograde conduction. Further ablation in the RA opposite the NCC at the site of earliest retrograde atrial activation during ORT restored sinus and eliminated retrograde AP conduction. A 52-year-old male with SVT and ECG with pre-excitation underwent EPS that confirmed an AS-AP with anterograde and retrograde conduction. Ablation was performed in the NCC resulting in immediate elimination of pre-excitation. Retrograde conduction was still present and confirmed by repeating electrophysiological maneuvers. Ablation was performed in the RA opposite the successful ablation site in the NCC, eliminating retrograde AP conduction., Conclusion: Two cases of AS-AP with anterograde and retrograde conduction and successful elimination of pathway conduction required a hybrid ablation approach from the NCC and RA. This approach may be helpful in other cases to improve success rates without using excessive ablation near the normal conduction system., (© 2023 Wiley Periodicals LLC.)