On the Tip of a Needle: A Safer Route to Septal Reduction in HOCM?

On the Tip of a Needle: A Safer Route to Septal Reduction in HOCM? | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Journal of Cardiovascular Electrophysiology This is a preprint and has not been peer reviewed. Data may be preliminary. 24 July 2025 V1 Latest version Share on On the Tip of a Needle: A Safer Route to Septal Reduction in HOCM? Author : Dana Johnson 0000-0001-6995-2294 [email protected] Authors Info & Affiliations https://doi.org/10.22541/au.175332437.77504743/v1 Published Journal of Cardiovascular Electrophysiology Version of record Peer review timeline 299 views 183 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract 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. On the Tip of a Needle: A Safer Route to Septal Reduction in HOCM? By Dana C. Johnson, MD, MPH The management of obstructive septal hypertrophic cardiomyopathy (HOCM) remains a challenging area within cardiology, particularly as clinicians weigh the risks and benefits of surgical myectomy and minimally invasive approaches such as alcohol septal ablation (ASA) or radiofrequency (RF) ablation for patients whose symptoms are refractory to medical therapy. Both surgical myectomy and ASA have been shown to improve survival in severe symptomatic HOCM but often come at the cost of perioperative complications, including complete heart block (CHB) (1,2). In this issue of the Journal of Cardiovascular Electrophysiology , Xu and colleagues contribute a thought-provoking preclinical study exploring the use of a novel retractable needle-tipped RF catheter for septal ablation in healthy canines. Endocardial RF ablation has previously been explored as an alternative to ASA or myectomy, but the threat to conduction anatomy remains a concern with outflow septal ablation (3–5). Xu et al. present an experimental comparison between septal ablation using a specialized RF needle catheter and a conventional cold saline–perfused RF catheter. They hypothesized that the needle catheter could deliver deeper, larger lesions—resulting in greater reduction in septal thickness and motion—while sparing the subendocardium, potentially preserving the conduction system. They argue that this approach offers advantages not only over classic RF ablation but also over existing surgical and minimally invasive approaches. Surgical myectomy, while effective, requires considerable expertise and often carries procedural risks due to its invasive nature and proximity to the cardiac conduction system. Myectomy can result in septal defect rates of 1–2%, CHB in up to 10%, and overall mortality rates of up to 2% (1,3,5). ASA, though less invasive, is highly dependent on favorable coronary anatomy, generally results in less septal reduction than myectomy, and is similarly associated with conduction system disturbances requiring pacemaker implantation. However, it appears to rely less on high-volume center experience for positive outcomes (2,6). The introduction of percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) has offered a promising direction by allowing deeper myocardial targeting with less reported damage to cardiac conduction. However, this technique remains technically demanding, with occasionally high complication rates and limited broad adoption to date (7,8). Xu et al. propose that the retractable needle-tipped catheter offers a more straightforward and potentially safer solution for intramyocardial ablation. By delivering RF energy deep into the septal tissue via a retractable needle, the technique may avoid the superficial endocardial damage seen with conventional RFCA while enabling more substantial lesion formation. The authors have adapted this approach—originally developed for refractory ventricular tachycardia—to target the interventricular septum, with early results presented in this manuscript. In their canine study, eight healthy dogs underwent septal ablation using either the novel needle catheter or a conventional irrigated RF catheter. The authors report that lesions created by the needle catheter were significantly deeper and wider, as confirmed by gross pathology and histological analysis. Functionally, dogs treated with the needle catheter exhibited a greater reduction in the amplitude of septal motion three months post-ablation, suggesting more extensive local myocardial impact. While interventricular septal thickness also declined in the needle group, between-group comparisons did not reach statistical significance, likely due to the small sample size. Importantly, Xu and colleagues observed no major procedural complications in either group. Cardiac function remained preserved, and electrocardiographic monitoring revealed no significant prolongation of PR or QRS intervals. These findings support the notion that deeper, subendocardial lesions created by the needle catheter may be less likely to injure the conduction system—a key concern with surgical myectomy, ASA, and endocardial RF approaches (Figure 1). Nonetheless, caution is warranted when interpreting the implications of this study. The animal model, though valuable for assessing procedural safety and lesion formation, lacks the anatomical and pathological complexity of HOCM in humans. The dogs used were healthy and did not exhibit the septal hypertrophy or fibrosis characteristic of the target patient population. This limits the translational relevance of the findings and necessitates further investigation in disease-relevant models. Additionally, while this study experienced no complications with the use of an intramyocardial RF needle ablation catheter, past experience in human ablation of refractory VT using a similar catheter has been limited by complications—experience that should continue to inform future efforts (9,10). This study has important limitations that preclude drawing therapeutic conclusions at this stage, including the small sample size, the absence of a clinical HCM animal model, and the overall lack of defined safety endpoints in either procedural arm. Additionally, while the authors compared the needle catheter to surface endocardial RF ablation, they did not include comparisons with ASA, PIMSRA, or myectomy. The absence of significant differences in electrocardiographic parameters between the needle and conventional groups also tempers some enthusiasm. One of the central theoretical advantages of intramyocardial ablation is the potential to spare the conduction system by avoiding energy delivery near the His-Purkinje network. However, in this study, both catheters demonstrated comparable safety profiles with respect to PR and QRS duration. While the needle catheter did not worsen conduction, neither did the conventional catheter, again pointing to the need for larger studies to discern true differences in procedural risk. Despite these limitations, the study should be viewed as a valuable proof of concept rather than a definitive therapeutic endorsement. The findings suggest that needle-tipped RF catheters can create controlled, transmural lesions in the interventricular septum with preserved cardiac function, and they introduce the plausible potential to reduce harm to the conduction system compared to other septal reduction modalities. These outcomes offer an encouraging starting point for further research, particularly in more clinically relevant animal models and, eventually, in human feasibility trials. Ultimately, Xu et al. provide us with a thoughtful and technically rigorous platform for future development. As the field of structural electrophysiology continues to evolve, novel tools such as the needle-tipped RF catheter may help bridge the gap between procedural simplicity and therapeutic depth. While the current data are preliminary, they invite a broader conversation about the next generation of septal reduction therapies—ones that are tailored, targeted, and minimally invasive. If the needle can live up to its potential for successful, endocardium-sparing septal reductive therapy, it may indeed prove to be a valuable addition to this historically complex therapeutic landscape. Should it continue to demonstrate a favorable safety profile, its comparison to established but sometimes fraught septal reduction approaches may advance the growing field of structural electrophysiology therapeutics. In conclusion, the authors are to be commended for introducing a novel application of needle-tip RF technology and supporting its feasibility with compelling early data. This study marks an important step toward refining catheter-based solutions for obstructive cardiomyopathy and sets the stage for further preclinical and translational investigations. As always, clinical enthusiasm should be tempered with careful validation, but the direction is both exciting and necessary. References Ommen, S. R., Maron, B. J., Olivotto, I., Maron, M. 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Circulation: Arrhythmia and Electrophysiology , 15 (8), e010347. https://doi.org/10.1161/CIRCEP.121.010347 Information & Authors Information Version history V1 Version 1 24 July 2025 Peer review timeline Published Journal of Cardiovascular Electrophysiology Version of Record 31 Jul 2025 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Collection Journal of Cardiovascular Electrophysiology Keywords clinical: cardiac anatomy clinical: catheter ablation – ventricular tachycardia clinical: electrophysiology – conduction disturbances Authors Affiliations Dana Johnson 0000-0001-6995-2294 [email protected] University of Illinois Chicago View all articles by this author Metrics & Citations Metrics Article Usage 299 views 183 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Dana Johnson. On the Tip of a Needle: A Safer Route to Septal Reduction in HOCM?. Authorea . 24 July 2025. 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