Abstract Background: Pulsed field ablation (PFA) has rapidly emerged as a promising alternative to conventional thermal ablation for atrial fibrillation (AF), offering tissue selectivity and procedural efficiency. However, recent evidence has raised concerns about its cerebral safety profile, particularly regarding silent cerebral lesions (SCLs) and microembolic signals (MES) detected by transcranial Doppler. Content: In light of the study “Comparison of cerebral micro-embolization detected by transcranial doppler examination between radiofrequency ablation and pulsed field ablation for atrial fibrillation,” this editorial discusses the unexpectedly high burden of cerebral MES observed with PFA—especially with certain catheter designs—compared with high-power short-duration radiofrequency ablation. Potential mechanisms include gas microbubble formation, microthrombus generation, and device- or technique-related air entrainment. These findings challenge the assumption that PFA is intrinsically safer with respect to cerebral embolization. Conclusion: While PFA represents a major technological advance in AF ablation, the emerging evidence underscores that not all PFA systems are equal regarding embolic safety. Device engineering, procedural optimization, and systematic neurological monitoring are essential to ensure that the benefits of this novel energy source are not offset by an “invisible” cerebral cost. Vigilance and continued innovation will be critical to secure both efficacy and neurological safety in the next generation of ablation technologies.

Addressing Air Intrusion in Pulsed Field Ablation Sheaths: A Step Toward Safer Ablation Procedures

Catheter ablation has become more efficient over time with the evolution of technology, but can come at a cost to efficiency and safety if not performed proficiently. We highlight efficiency in a single lab setting in a resource-constrained environment using the LEAN/Six Sigma principles of simplification, waste elimination, and standardization.

Per authors instructions, no abstract required Invited Editorial to: “Clinical Predictors of Recurrent Cavo-Tricuspid Isthmus Flutter After Catheter Ablation in Patients with D-Transposition of the Great Arteries” by Grubb A et al Manuscript ID: e5851195-dced-453d-b108-49d1103d67da

We read with great interest the recent article by Bruss J et al. on hemolysis induced by pulsed-field ablation (PFA) systems. The authors present compelling evidence that hemolysis varies substantially between catheter designs, with focal catheters such as the lattice-tip focal catheter (LTFC) resulting in significantly less hemolysis than large-footprint catheters like the pentaspline (PSC) and variable-loop circular catheter (VLCC). This analysis provides important insights into an under-recognized safety consideration, particularly as PFA continues to gain clinical momentum. We would like to highlight an additional and potentially modifiable contributor to hemolysis: intravenous fluid (IVF) administration.

Editorial

Balancing Efficiency and Outcomes in the Evolution of Catheter AblationIbrahim Hasan MD, Marwan M. Refaat MDDepartment of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, LebanonRunning Title: Balancing Efficiency and Outcomes in AblationWords: 696 (excluding the title page and references)Keywords: Catheter Ablation, Cardiovascular Diseases, Cardiac ArrhythmiasFunding: NoneDisclosures: NoneCorrespondence:Marwan M. Refaat, MD, FACC, FAHA, FHRS, FASE, FESC, FACP, FRCPTenured Professor of MedicineDirector, Cardiovascular Fellowship ProgramDepartment of Internal Medicine, Cardiovascular Medicine/Cardiac ElectrophysiologyDepartment of Biochemistry and Molecular GeneticsAmerican University of Beirut Faculty of Medicine and Medical CenterPO Box 11-0236, Riad El-Solh 1107 2020- Beirut, LebanonFax: +961-1-370814Clinic: +961-1-759616 or +961-1-355500 or +961-1-350000/+961-1-374374 Extension 5800Office: +961-1-350000/+961-1-374374 Extension 5353 or Extension 5366 (Direct)Email: mr48@aub.edu.lbThe recent review “Catheter Ablation: Evolution and Efficiencies” offers a timely and insightful synthesis of the historical evolution, current practice, and procedural imperatives surrounding catheter ablation in electrophysiology (EP) [1]. As catheter-based interventions increasingly define the standard of care for arrhythmias—including atrial fibrillation, atrial flutter, supraventricular tachycardia, and ventricular tachycardias—understanding procedural efficiency has never been more critical. The review excels in contextualizing the historical progression of catheter ablation technologies, from initial direct current ablation to radiofrequency ablation (RF), cryoballoon, and the emerging pulsed field ablation (PFA). By tracing technical evolution alongside procedural adaptations, the authors illustrate how efficiency has been both a driver and a product of technological advancement. For instance, novel irrigated-tip RF catheters and contact force–sensing technologies have allowed for shorter procedure times and better ablation outcomes respectively [2], demonstrating the interplay of efficiency and efficacy. Moreover, PFA offers single-shot approaches [3], and it significantly reduced procedure time while maintaining high rates of pulmonary vein isolation as shown in multiple trials [4]. The review methodically addresses practical strategies to optimize EP lab efficiency. Ultrasound-guided femoral access, for example, is emphasized as a method to reduce the vascular complications and puncture time [5]. Anesthesia considerations are also thoughtfully discussed, highlighting that general anesthesia can decrease procedure times and improve ablation efficacy without compromising safety [6], while moderate sedation may remain sufficient for less complex arrhythmias. Invasive hemodynamic monitoring is addressed, with the authors recommending selective use of arterial lines for patients with impaired cardiac function or high procedural complexity, reflecting a balance between procedural oversight and resource utilization, as shown in a multi-center study that catheter ablation for atrial fibrillation can be safely conducted without reliance on invasive hemodynamic monitoring [7].The review also provides a detailed discussion of catheter selection and mapping strategies. High-density and omnipolar mapping techniques have been shown to reduce procedure time and enhance ablation accuracy, thereby improving both efficiency and outcomes [8, 9]. Of particular interest is the emerging role of PFA, which uses irreversible electroporation to rapidly create myocardial lesions while minimizing collateral tissue injury [3]. Studies report acute pulmonary vein isolation rates reaching 100%, with procedure times averaging under 100 minutes and low complication rates [10, 11]. The integration of PFA with three-dimensional mapping systems further consolidates mapping and ablation into a single workflow, exemplifying the potential for procedural streamlining without compromising patient safety [12].Despite its strengths, the review has some limitations. While procedural efficiency is emphasized, economic analyses are limited. Cost-effectiveness, total resource utilization, and comparative expenditures across different ablation modalities are important considerations that are only partially addressed, as a recent study found that while PFA had shorter procedure times compared to cryoballoon ablation and RF ablation, it was significantly more costly [13]. Finally, the review briefly acknowledges operator experience and learning curves, but high-volume centers consistently demonstrate superior outcomes [14], and structured training programs will be critical for the safe adoption of novel technologies.Building on the foundation established in the review, several avenues for future research emerge. Detailed economic and resource utilization analyses across different healthcare settings would provide valuable guidance for sustainable implementation of advanced ablation technologies. Multicenter registry data can clarify the translation of efficiency gains into real-world outcomes and inform best practices for training and standardization. Risk stratification models that integrate patient characteristics, procedural parameters, and device selection could further optimize outcomes while maintaining high efficiency. Finally, the integration of artificial intelligence in mapping, catheter navigation, and lesion assessment may represents a promising frontier for standardizing procedural efficiency and enhancing patient safety.In conclusion, the review provides a comprehensive, timely, and practical synthesis of a rapidly evolving field. By framing efficiency as a balance between procedural speed, safety, and efficacy, the review offers actionable guidance for clinicians navigating increasingly complex EP interventions. Its integration of historical context, technical evolution, and emerging technologies underscores the transformative potential of innovation in enhancing patient outcomes. Nonetheless, systematic evaluation of safety, cost-effectiveness, and long-term outcomes remains essential to ensure that efficiency gains translate into meaningful clinical benefit. Future research focused on comparative effectiveness, patient-centered outcomes, and AI-driven procedural optimization will be key to advancing the field of electrophysiology while maintaining high-quality care.

Cardiac contractility modulation – Making it workNiraj Varma MA, MD, PhD, FRCP

We read with great interest the study by Sam et al. entitled” Immediate Leg Mobilization is Feasible After Catheter Ablation of Atrial Fibrillation Using Large Vascular Access Sheaths (Pulsed Field and Cryoballoon Ablation)” [1](#ref-0001). demonstrating the feasibility of immediate leg mobilization following catheter ablation of atrial fibrillation using suture-mediated vascular closure devices. Their findings of comparable vascular complication rates between immediate mobilization and traditional 4-hour bed rest, coupled with significantly shorter discharge times, address an important clinical question impacting both patient comfort and healthcare efficiency. While we commend this valuable contribution, we wish to highlight two critical considerations that warrant discussion for optimal clinical implementation. A limitation is the lack of systematic bleeding risk stratification in the immediate mobilization protocol. Although the study reports uniform anticoagulation management, it fails to incorporate validated bleeding risk assessment tools such as HAS-BLED scores[2](#ref-0002) or patient-specific factors including renal function, concomitant antiplatelet therapy, and prior bleeding history. In clinical practice, elderly patients with multiple comorbidities, those with recent bleeding episodes, or patients requiring dual antiplatelet therapy represent higher-risk populations who may require modified protocols despite successful vascular closure.Future protocols should integrate validated bleeding risk scores (HAS-BLED, CRUSADE) to guide patient selection and incorporate risk-stratified mobilization timelines, with high-risk patients receiving extended bed rest periods[3](#ref-0003) rather than universal immediate mobilization. The most significant methodological concern involves confounding factors that threaten internal validity. The immediate mobilization protocol implementation in 2024 coincided with institutional adoption of pulsed-field ablation, creating a striking imbalance: 72% of immediate mobilization cases utilized PFA versus only 5% in the bed rest group. Furthermore, the bed rest cohort demonstrated significantly higher comorbidity burden, including greater prevalence of coronary artery disease (36% vs 23%), diabetes (37% vs 17%), and heart failure (35% vs 21%)[1](#ref-0001).Future studies should employ propensity-matched analyses [4](#ref-0004) adjusting for baseline characteristics, conduct procedure-specific subgroup analyses, and ideally implement prospective randomized trials with contemporary matched controls to eliminate temporal confounding. In conclusion, while immediate mobilization appears promising, robust implementation requires individualized bleeding risk assessment and methodologically rigorous studies that isolate the true effect of mobilization strategy from procedural and temporal confounders. These enhancements would provide clinicians with evidence-based guidelines for safe patient selection in this evolving approach to post-procedural care.

Clarifying the Role of Intermittent Pre-excitation in Risk Stratification: A Response to Abbas et al.Antonio Gianluca Robles1,2,*, Antonio Scarà2,3, Luigi Sciarra2,3(1) Cardiology Department, L. Bonomo Hospital, Andria, Italy(2) University of L’Aquila, Department of Clinical Medicine, Public Health, Life and Environmental Science, L’Aquila, Italy(3) Casa di Cura Di Lorenzo, Avezzano, Italy*Corresponding Author: Antonio Gianluca Robles, MD, PhD, gianlucarobles24@gmail.com;+39 3278678658 (1) Cardiology Department, L. Bonomo Hospital, Andria, Italy (2) University of L’Aquila, Department of Clinical Medicine, Public Health, Life and Environmental Science, L’Aquila, ItalyORCID iD: 0000-0002-2150-3788Aknowledgements: this response to letter to the Editor is written on behalf of all the authors of the paper: Robles AG, Palamà Z, Santoro F, Rauber M, Antolič B, Gianfrancesco D, Bartolomucci F, Pellegrino P, Alfieri S, Borelli A, Scarà A, Luca GM, de Ruvo E, Calò L, Jan M, Pernat A, Romano S, Sciarra L. Intermittent Ventricular Pre-Excitation: Clinical Features and Electrophysiological Properties. J Cardiovasc Electrophysiol. 2025 Aug 7. doi: 10.1111/jce.70035.We thank Abbas et al.1 for highlighting the limitations of our study and for fostering a critical discussion on this important topic. We believe their comments underline the inherent challenges of explaining natural phenomena using statistical methods alone.As outlined in our original paper2, the primary aim of our study was to describe the clinical and electrophysiological differences between patients with persistent versus intermittent pre-excitation, as well as between symptomatic and asymptomatic individuals with intermittent pre-excitation. To this end, we analyzed data from a multicenter registry that was predominantly, though not exclusively, retrospective. Consequently, the study was not powered ad hoc, as would be the case in a prospective design.Asymptomatic intermittent pre-excitation is a rare condition. Achieving a sample size of 50–100 patients with both characteristics, as suggested by Abbas et al.1, would have required a study population at least 5 to 10 times larger and a substantially longer enrollment period. For this reason, we emphasize that our objective was strictly descriptive rather than inferential, and based solely on the available data.Prior to the release of the 2019 ESC guidelines3 – and to some extent still today – there has been broad consensus that asymptomatic patients with pre-excitation should not routinely undergo an electrophysiological (EP) study, except in cases involving athletes or specific occupational indications. Conversely, the presence of palpitations in a pre-excited patient, even in the absence of documented arrhythmias, was often deemed a reasonable indication for EP evaluation. This historical context is essential to acknowledge potential selection bias. Notably, in our study, the asymptomatic individuals were truly asymptomatic, a key point in our view, as this subgroup presents the greatest uncertainty in terms of risk stratification. Furthermore, from a semantic standpoint, a “symptom” refers to a subjective experience reported by the patient (e.g., palpitations), whereas a “sign” denotes an objective finding (e.g., documented AVRT/AF).Although the EP studies were conducted at different centers and by various operators over time, all were performed in conscious patients without general anesthesia. Intravenous isoproterenol was administered only when warranted – specifically, when no AVRT was inducible at baseline, and there was no evidence of multiple accessory pathways or ERP/SPERRI ≤250 msec – that are widely accepted as markers of arrhythmic risk and indications for ablation.3Regardless of the center or operator, isoproterenol was administered following a standardized protocol, aiming for a 25–30% increase in heart rate to ensure adequate adrenergic stimulation prior to EP maneuvers.4 Its use is well established and routinely practiced in EP labs worldwide.It is important to reiterate that the only extrinsic factors currently recognized to influence accessory pathway conduction are adrenergic stimulation and the effect of antiarrhythmic drugs.3This stands in contrast to the hypothesis proposed by Abbas et al.1 regarding a potential role for central sleep apnea – an association that remains speculative. Moreover, central sleep apnea is a comorbidity predominantly observed in the elderly, a population in which risk stratification is generally less critical.Lastly, arrhythmic risk in patients with intermittent pre-excitation is neither absent nor negligible, as confirmed by case reports and by our own findings.2-3-5 Specifically, among the nine asymptomatic intermittent patients in our study, five exhibited inducible AVRT/AF, and four had ERP/SPERRI ≤250 msec. We strongly believe that there is now sufficient evidence to consider intermittent pre-excitation an unreliable indicator of low risk. Accordingly, given the limitations of non-invasive risk stratification, EP study should be considered – particularly in younger individuals (<40 years).To be candid, the continued prognostic distinction between persistent and intermittent pre-excitation may no longer be justified. These should instead be regarded as purely electrocardiographic findings.

Trends and Disparities in Ventricular Tachycardia-Related Mortality According to Cardiomyopathy Type in the United StatesMohammad Ali Sheffeh, M.D1-2., Jeanne du Fay de Lavallaz, MD3., Andres Estrada Magana, M.D2., Konstantinos C. Siontis2, MD Jackson J. Liang, D.O31 Department of Internal Medicine, Henry Ford Warren Hospital, Warren, MI, USAMsheffe1@hfhs.org2 Department of Cardiovascular Medicine, Mayo Clinic Rochester, Rochester, MN, USA estradamagana.andres@mayo.edu, Siontis.Konstantinos@mayo.edu3 Department of Clinical Electrophysiology, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, USAdufaydej@med.umich.edu, liangjac@med.umich.edu

Although major investigations on the AF risk after AFL ablation have been published, the natural history of right AFL after cardioversion is much less understood. The authors sought to the largest historical cohort on the subject in order to establish the true risk of AFL and AF recurrence after AFL DCCV. Overall, 860 individuals with atrial arrhythmias were included and underwent their first DCCV. The median time to recurrence was 3.4 months in the AF cohort (n=572), and 1.7 years in the AFL cohort (n=288). The overall recurrence of atrial arrhythmias was 96.0% for the AF group and 78.8% for the AFL group (p<0.001). In the AF group, most of the recurrent rhythm was AF (92.7%), while only a small percentage was AFL (7.3%). Conversely, the AFL cohort showed recurrence of AF in only 32.6% of cases and 67.4% reverted back to AFL. AFL recurrences represented 53% of the cases within the entire AFL population. the authors created a clinical predictive risk score for predicting recurrence risk after the first DCCV in this pure AFL population. the REAL-PDX risk score stratified by ≥3 vs. <3 in the AFL validation cohort (n=112) showed a significantly shorter median time to recurrence (125 vs. 800 days; p<0.001) and a higher risk of recurrence of atrial arrhythmia (HR: 3.74; 95% CI [1.93-7.24]).This study will certainly remain a benchmark in the field of right AFL natural history after DCCV.

Dear Editor, We read with interest the study by Robles et al. examining intermittent ventricular pre-excitation in patients with Wolff-Parkinson-White syndrome (1). This registry contributes valuable data to an underexplored area, however, we have observed methodological concerns that constrain the clinical applicability of their findings. First, the study’s most significant limitation lies in the imbalance between symptomatic and asymptomatic patients within the intermittent pre-excitation group. With only 9 asymptomatic patients among 79 with intermittent pre-excitation, the statistical power to detect meaningful differences is compromised (1). This sample size cannot reliably exclude clinically important differences in electrophysiological parameters between symptomatic and asymptomatic intermittent patients, rendering the study’s conclusions about risk equivalence statistically unsupported. Power calculations would likely require 50-100 asymptomatic patients per group to detect moderate effect sizes in accessory pathway properties (2). Second, the heterogeneous use of isoproterenol across centers, along with varying sedation practices and equipment preferences creates systematic variability that could obscure the true differences between groups (1). Isoproterenol is a powerful heart stimulant that can make accessory pathways conduct electricity faster and trigger arrhythmias more easily than would occur naturally in patients’ daily lives (3). Studies comparing provoked versus baseline electrophysiological parameters show that catecholamine stimulation can dramatically alter pathway characteristics, potentially masking important differences between intermittent and persistent pre-excitation groups (4). Third, the definition used for symptomatic patients in this study as those reporting palpitations regardless of documented arrhythmias, accounts for another methodological weakness. This broad categorization does not distinguish between patients with confirmed tachyarrhythmias and those with non-specific symptoms, potentially misclassifying patients and obscuring true risk differences (1). Considering that symptom perception can be influenced by awareness of the cardiac condition, this classification bias could systematically inflate the apparent similarity between groups. Finally, the study’s international, retrospective, multicenter design introduces selection bias and heterogeneity in patient populations, referral practices and electrophysiological techniques. The unmeasured confounders could account for the observed similarities between groups given the relatively small effect sizes being studied. The 20-year data collection period spans through evolutions in clinical practice, diagnostic criteria and risk assessment approaches and this introduces temporal bias which could confound contemporary relevance. Exclusion of patients with central sleep apnea or inadequate monitoring may also have systematically excluded important subgroups. Future studies should prioritize standardized protocols, adequate sample sizes and prospective data collection to address these limitations. In conclusion, the study’s deduction that intermittent pre-excitation requires invasive assessment does align with evolving clinical evidence which suggests that non-invasive risk stratification has limited negative predictive value in excluding high-risk pathways. However, we believe this recommendation should be based on the established limitations of non-invasive testing rather than the equivalence of risk parameters demonstrated in this study.

Title: Pulsed-Field Ablation and Hemolysis: Critical Insights into a Novel TechnologyAuthor: Masateru Takigawa, MD, PhDAffiliation: Institute of SCIENCE TOKYOKey words: Pulsed-Field Ablation (PFA), Hemolysis, Catheter, Atrial Fibrillation

Introduction Cannabis use is significantly increasing worldwide yet its cardiovascular effects and arrhythmogenic potential remain unclear. As legalization expands, it is critical to understand public health risks and clinical implications. This study evaluates the relationship between cannabis use and the risk of arrhythmias using a large, real-world dataset. Methods This retrospective cohort study utilized de-identified electronic health records from 68 U.S. healthcare organizations within the TriNetX network. A total of 210,817 adult cannabis users were identified and matched 1:1 with 210,817 ibuprofen users using propensity score matching across 17 baseline variables, including demographics, cardiovascular risk factors, and medication use. The primary outcomes were incident diagnoses of atrial fibrillation/flutter (AF/AFL), paroxysmal tachycardia, premature beats, and ventricular tachycardia/fibrillation (VT/VF). Outcomes were assessed using Cox proportional hazards models and Kaplan-Meier survival analyses. Results Cannabis use was significantly associated with an increased risk of multiple arrhythmias compared to ibuprofen use. The incidence of AF/AFL was 1,895 vs 1,332 cases (HR = 1.549, 95% CI: 1.444–1.662, p < 0.001). Paroxysmal tachycardia occurred in 1,065 vs 672 patients (HR = 1.791, 95% CI: 1.626–1.973, p < 0.001), and premature beats in 1,135 vs 745 patients (HR = 1.739, 95% CI: 1.585–1.908, p < 0.001). The most pronounced relative risk was observed for VT/VF, with 97 vs 35 cases (HR = 3.078, 95% CI: 2.089–4.533, p < 0.001). All associations remained statistically significant after adjustment, and Kaplan-Meier curves demonstrated lower arrhythmia-free survival in cannabis users across all endpoints. Conclusion Cannabis use was associated with an increased risk of multiple arrhythmias, particularly atrial fibrillation and ventricular arrhythmias. These findings highlight the need for further research on the cardiovascular effects of cannabis and reinforce the importance of patient counseling regarding its potential arrhythmogenic risks.

Reply to – “Cardiopulmonary Exercise Testing-Guided Beta-Blocker Dosing in Long QT syndrome: Genotype, Methodology, and Adherence Concerns”Iqbal El Assaad, MD;Cleveland Clinic Children’s Hospital - Pediatric Cardiology9500 Euclid Avenue , Cleveland, Ohio 44195United Stateseli5@ccf.orgPeter F. Aziz, MDCleveland Clinic Children’s Hospital - Pediatric CardiologyCleveland, OhioUnited Statesazizp@ccf.orgDear Editor,We appreciate the thoughtful commentary and concerns raised by Kemar et al. and thank the authors for highlighting important limitations – many of which we discussed in our manuscript. That said, perhaps a few key points deserve further emphasis to ensure our central message remains clear.Our manuscript portrays the real-world experience of managing patients with long QT syndrome (LQTS) as it specifically pertains to beta-blocker therapy tolerance. While we always strive to follow guidelines recommending maximal dosing, the reality in clinical practice is that not all patients can tolerate this approach. As demonstrated in our study, at least one-third of patients experienced significant side effects that precluded the use of maximal therapy. We believe that some beta-blocker therapy is better than none, particularly when the alternative is non-adherence due to intolerable side effects.This practical dilemma is one clinicians often face: how to provide arrhythmic protection while preserving quality of life? For patients who are intolerant of maximal therapy, we advocate for anindividualized approach – utilizing the exercise stress test (EST) to objectively assess chronotropic suppression and determine whether the patient is deriving measurable benefit from beta-blocker therapy. Currently, EST is the only tool we have to quantify therapeutic effect in this context. We could not agree more with the authors’ conclusion: “Guideline-directed maximal beta-blocker therapy remains the standard for LQTS patients, with individualized approaches for those intolerant to standard therapy, supervised by specialized experts .” In fact, our manuscript states:“It is important to note that submaximal dosing should not be used as a universal approach, as there are still patients who experience breakthrough events despite being on submaximal therapy. Therefore, it is crucial that this approach is implemented intentionally and under the guidance of an experienced inherited arrhythmia specialist after careful risk stratification of the patient.”In our clinical practice, we aim to find the optimal balance – a beta blocker dose that provides adequate chronotropic suppression while minimizing side effects that could compromise adherence. It is also worth mentioning that we also routinely discuss the role of left cardiac sympathetic denervation (LCSD) therapy in patients who are intolerant of beta-blocker therapy, especially those who are considered high risk (i.e. males with LQTS1 with QTc> 550 ms, post pubertal females with LQTS2 with QTc>500 ms). However, it should be noted that LCSD comes with its own set of complications.1 Again, when options are limited, we believe that objective assessment – though imperfect – is preferable to nothing. The proposed approach is not intended to replace maximal therapy, but to optimize care for those who cannot tolerate it.Regarding the definition of adequate beta blockade, we acknowledge the concern that our 15-20% heart rate blunting threshold during maximal exercise may appear arbitrary. However, we found evidence to guide this decision in the literature. We followed Dr. Krahn’s practical approach, as outlined in his review article on congenital LQTS, where he describes using this threshold to demonstrate adequate effect.2This is also consistent with our clinical practice.Finally, we concur with the authors’ comments on medication adherence. Adherence is difficult to measure reliably. Although we address adherence at every clinic visit, this remains a common limitation across all therapeutic areas. We also agree we should not assume that beta blockers have a protective effect due to heart rate suppression only and that the full mechanism underlying protection is multifaceted and not completely understood. This underscores yet another reason to aim for maximal therapy in all patients and utilize the individualized EST guided plan in those who are intolerant of beta-blockers to help them maximize compliance and medication adherence. Importantly, this strategy should be implemented only under the guidance of an experienced inherited arrhythmia specialist and must be tailored to each patient’s specific risk for life-threatening arrhythmias.References:Niaz T, Bos JM, Sorensen KB, Moir C, Ackerman MJ. Left Cardiac Sympathetic Denervation Monotherapy in Patients With Congenital Long QT Syndrome. Circ Arrhythm Electrophysiol. 2020 Dec;13(12):e008830. doi: 10.1161/CIRCEP.120.008830. Epub 2020 Nov 16. PMID: 33198487.Krahn AD, Laksman Z, Sy RW, et al. Congenital Long QT Syndrome.J Am Coll Cardiol EP . 2022;8:687–706

Response to the Letter to the Editor Regarding “Temporary Restoration of Sinus Rhythm Improves Outcomes of Catheter Ablation for Longstanding Persistent Atrial Fibrillation”

Septal reduction therapy remains a cornerstone in the management of drug-refractory obstructive hypertrophic cardiomyopathy (HOCM), with surgical myectomy and alcohol septal ablation (ASA) as established modalities. However, both approaches are limited by procedural morbidity, particularly injury to the cardiac conduction system. This editorial examines a preclinical investigation by Xu et al., which evaluates a novel retractable needle-tipped radiofrequency (RF) ablation catheter designed to deliver intramyocardial energy with the aim of preserving the subendocardium. Using a healthy canine model, this technique generated significantly deeper and broader lesions compared to conventional surface RF ablation, with associated reductions in septal motion and no observed compromise in conduction parameters or global cardiac function. While constrained by the use of healthy dogs rather than a true HOCM model and a small sample size, the findings point to the potential of this approach as a minimally invasive, conduction-sparing alternative for septal reduction, while leaving many remaining questions. This commentary contextualizes the study within the evolving field of structural electrophysiology and highlights the imperative for further translational and clinical evaluation of novel ablation technologies.