High-power short-duration radiofrequency ablation for atrial fibrillation: There is still a country for “old men”

Abstract

High-power short-duration (HPSD) and very-HPSD (vHPSD) radiofrequency (RF) ablation have emerged as important advances in catheter ablation for atrial fibrillation (AF). By delivering higher power over shorter durations, these approaches aim to improve lesion quality, procedural efficiency, and clinical outcomes while maintaining procedural safety. The recent introduction of pulsed-field ablation (PFA) has challenged the role of thermal energy sources and raised questions regarding the future position of HPSD RF ablation in AF treatment. This narrative review summarizes the current evidence regarding the biophysical principles, procedural characteristics, efficacy, and safety of HPSD and vHPSD RF ablation. Data from mechanistic studies, randomized controlled trials, observational studies, meta-analyses, and contemporary consensus documents were reviewed, with particular focus on pulmonary vein isolation, posterior wall isolation, linear ablation, and comparisons with emerging PFA technologies. HPSD and vHPSD ablation generate lesions predominantly through resistive heating, producing broader and more homogeneous lesions while reducing RF application time. Randomized trials and meta-analyses consistently demonstrate shorter procedure duration, reduced RF delivery time, improved first-pass pulmonary vein isolation, and non-inferior or superior arrhythmia-free survival compared with conventional low-power long-duration RF ablation. Safety outcomes are generally comparable, although concerns regarding steam pops and cerebral embolic events remain dependent on catheter technology and procedural protocols. While PFA offers a non-thermal, tissue-selective alternative with promising safety and efficiency profiles, emerging evidence suggests that clinical efficacy remains largely comparable between PFA and HPSD/vHPSD strategies. HPSD and vHPSD RF ablation represent mature, effective, and efficient approaches for AF ablation, supported by extensive mechanistic and clinical evidence. Despite the rapid adoption of PFA, current data do not support the replacement of HPSD RF ablation. Rather, HPSD is likely to remain an important component of contemporary AF ablation, complementing emerging non-thermal technologies and providing a versatile strategy across a broad range of clinical scenarios.

Key Words: High-power short-duration; Atrial fibrillation; Catheter ablation; Radiofrequency; Lesion formation; Biophysics; Pulsed field ablation

Core Tip: High-power short-duration (HPSD) is the latest development in radiofrequency (RF) catheter ablation. HPSD has redefined the RF ablation landscape, offering proven advantages over low-power long-duration RF ablation in both safety and efficacy. However, there are still safety issues related to RF thermal effects. In addition, even when following standardized protocols, HPSD RF ablation remains operator-dependent. Pulsed field ablation (PFA) is an innovative, non-thermal ablation technique that employs pulsed electric fields to ablate myocardial tissue selectively, sparing adjacent non-cardiac structures. PFA seems more reproducible, reducing procedural time while maintaining non-inferior efficacy. In the era of PFA, HPSD RF ablation should therefore be viewed not as a technology being replaced, but rather as a mature and efficient strategy that will likely coexist with emerging non-thermal ablation modalities.

INTRODUCTION

High-power short-duration (HPSD) is the latest development in radiofrequency (RF) ablation of atrial fibrillation (AF). This approach involves using a higher power setting, usually > 50 W, for shorter applications. HPSD stands out for its advantages over traditional low-power, long-duration ablation protocols. The most notable benefits include increased procedural efficiency, shorter overall ablation times, and more accurate control of lesion depth, reducing the risk of collateral damage to nearby structures, such as the esophagus. The most recent studies have shown that HPSD is associated with comparable or superior success rates compared to traditional methods, with a reduction in complications, including pulmonary vein stenosis and cardiac perforation. Despite these promising results, some challenges remain related to the thermal effect of RF and the need to standardize HPSD ablation protocols and evaluate long-term effects. Pulsed field ablation (PFA) is an innovative, non-thermal ablation technique that employs pulsed electric fields to ablate myocardial tissue selectively. This emerging approach has garnered significant attention as a potentially transformative method for treating AF. PFA utilizes the principle of electroporation, delivering ultra-short, high-voltage electric pulses that create microscopic pores in cell membranes, leading to irreversible cell damage. The selective nature of PFA allows for targeted ablation of cardiac myocytes while sparing adjacent non-cardiac structures such as the esophagus and phrenic nerve. Clinical studies have demonstrated promising results, with PFA showing comparable or superior efficacy and maintaining procedural safety. Key advantages of PFA include shorter procedure times, reduced risk of complications, and the absence of collateral thermal injury. Moreover, the non-thermal nature of the technique may minimize post-procedural inflammation and scarring, potentially decreasing the recurrence of arrhythmias. Despite these advantages, challenges remain, including the need for optimized catheter design, standardized protocols, and long-term data on efficacy and safety. As research progresses, PFA holds the potential to redefine the landscape of AF ablation, offering a safer and more efficient alternative to traditional methods. In this review, we comprehensively discuss the clinical and electrophysiological features of HPSD.

LITERATURE SEARCH

This article was conducted as an expert narrative review of the current evidence regarding HPSD and very-HPSD (vHPSD) RF ablation for AF. A structured literature search was performed in PubMed/MEDLINE, EMBASE, and Google Scholar to identify relevant publications from January 1990 to February 2026. Search terms included combinations of: “high-power short-duration”, “very-high-power short-duration”, “HPSD”, “vHPSD”, “radiofrequency ablation”, “atrial fibrillation”, “pulmonary vein isolation”, “ablation index”, “lesion formation”, “posterior wall isolation”, “mitral isthmus”, “cavotricuspid isthmus”, and “pulsed-field ablation”. Additional articles were identified through manual review of reference lists from relevant studies, reviews, and consensus documents.

Eligible publications included randomized controlled trials, prospective and retrospective observational studies, meta-analyses, systematic reviews, consensus statements, and mechanistic studies investigating the biophysical principles, procedural characteristics, efficacy, and safety of HPSD/vHPSD ablation. Studies not available in English, conference abstracts without full-text publication, duplicate reports, and publications lacking relevant clinical or mechanistic data were excluded. Given the narrative nature of this review, formal systematic review methodology, risk-of-bias assessment, and quantitative meta-analysis were not performed. The final selection of studies was based on scientific relevance, methodological quality, and their contribution to understanding the evolving role of HPSD ablation in the contemporary era of PFA.

BIOPHYSICAL BASIS AND CLINICAL IMPLICATIONS OF HPSD RF ABLATION

RF ablation produces myocardial injury through resistive (Joule) heating, resulting in protein denaturation and coagulative necrosis when tissue temperature exceeds critical thresholds for a sufficient duration. Tissue injury begins at approximately 45 °C, with partially reversible cellular dysfunction and transient myocardial stunning observed below 50 °C, whereas temperatures exceeding 50 °C result in irreversible and durable myocardial necrosis[1]. Lesion formation is governed by two mechanisms: Resistive heating and conductive heating. Resistive heating occurs at the electrode-tissue interface, where current density is highest, and determines the initial lesion geometry. Conductive heating represents the passive spread of heat to deeper and adjacent tissue layers and is primarily time-dependent, contributing to lesion depth but also increasing the risk of collateral injury to surrounding structures, such as the esophagus[2,3]. Conventional low-power long-duration (LPLD) RF ablation relies on relatively lower power delivered over prolonged application times (typically 25-35 W for 30-60 seconds), thereby allowing conductive heating to extend lesion depth. While this approach may be advantageous in thicker myocardial regions, it also prolongs thermal exposure and increases dependence on catheter stability, irrigation, and local convective cooling. Moreover, prolonged conductive heating may increase the risk of extracardiac thermal injury, particularly along the posterior wall (PW) of the left atrium (LA). In contrast, HPSD RF ablation shifts lesion formation toward greater resistive heating by delivering higher power over shorter time intervals (typically 45-50 W for 2-15 seconds, depending on anatomical location). Because most RF energy is absorbed within the first 1-1.5 mm of tissue adjacent to the electrode, higher power delivery increases the volume of tissue rapidly heated above the critical necrotic threshold (> 50 °C), thereby promoting lesion formation while limiting the duration available for conductive heat spread[4,5]. This results in lesions that are characteristically wider and more homogeneous, but relatively shallower compared with conventional ablation. These lesion characteristics are particularly well suited for pulmonary vein isolation (PVI), as left atrial antral wall thickness is generally less than 4 mm, allowing reliable transmural lesion formation while minimizing excessive conductive heating[3,6,7]. The shorter duration of HPSD energy delivery may also reduce the impact of catheter instability caused by cardiac and respiratory motion. In conventional ablation, prolonged applications increase the likelihood of micro-displacement and uneven energy delivery, which may result in tissue edema and incomplete lesion formation. By contrast, the rapid energy delivery associated with HPSD ablation allows more consistent lesion formation within shorter periods of stable catheter contact, thereby improving lesion contiguity and durability. This mechanism likely contributes to the observed reductions in acute pulmonary vein reconnection and improved first-pass isolation rates associated with HPSD ablation[5,6]. These biophysical characteristics are particularly relevant when ablating the PW of the LA, where concerns regarding esophageal injury may limit energy delivery during conventional ablation. Because HPSD ablation reduces dependence on prolonged conductive heating, it may facilitate more effective lesion formation while potentially limiting heat transfer to adjacent extracardiac structures. Experimental studies have demonstrated that HPSD ablation produces lesions with larger surface areas and shallower depths, thereby limiting the propagation of conductive heat. However, lesion depth may be insufficient in thicker atrial regions, such as the mitral isthmus (MI), highlighting the importance of tailoring ablation strategies to regional myocardial thickness[3,7].

Beyond biophysical considerations, HPSD ablation offers important procedural advantages. Multiple studies have demonstrated significant reductions in RF delivery time, total procedure duration, left atrial dwell time, and fluoroscopy exposure. These improvements enhance procedural efficiency, reduce patient exposure to anesthesia, intravenous fluids, and anticoagulation, and decrease radiation exposure for both patients and healthcare personnel. Importantly, overall complication rates appear comparable between HPSD and conventional RF ablation strategies, supporting the safety of this approach when appropriate protocols and monitoring techniques are used[8]. Randomized and observational data consistently demonstrate that HPSD ablation provides procedural efficiency gains while maintaining clinical effectiveness. In particular, improved arrhythmia-free survival has been observed in patients with paroxysmal RF, likely reflecting improved lesion durability and higher-quality PVI. However, outcomes in persistent AF remain more variable, likely due to the need for deeper or more extensive lesion sets in structurally remodeled atria[8-11].

vHPSD ablation represents a further evolution of this strategy, using ultra-high power (e.g., 90 W for 4 seconds) delivered under temperature-controlled conditions. These systems actively modulate power delivery to maintain target temperatures, allowing rapid lesion formation while minimizing excessive heating and reducing the risk of steam pops or tissue overheating. Emerging evidence suggests that temperature-controlled vHPSD ablation may further improve procedural efficiency while maintaining safety and effectiveness, particularly when combined with personalized strategies based on regional atrial wall thickness[3,6,12]. Despite these advantages, safety considerations remain important. Rapid tissue heating may increase the risk of steam pops and embolic phenomena if energy delivery is not carefully controlled. Therefore, optimal lesion formation during HPSD and vHPSD ablation depends on precise catheter-tissue interaction, including stable contact force, appropriate inter-lesion spacing, and real-time monitoring of impedance, temperature, and lesion indices. Contemporary temperature-controlled systems and advanced lesion metrics may further improve the safety and reproducibility of this approach[4,13]. Overall, current evidence supports HPSD and vHPSD RF ablation as efficient and effective alternatives to conventional ablation strategies. These approaches improve procedural efficiency and may enhance lesion durability while maintaining comparable safety profiles. However, lesion characteristics and clinical outcomes remain dependent on appropriate patient selection, regional myocardial thickness, catheter technology, and procedural technique. Further randomized studies are warranted to define optimal ablation parameters and confirm long-term clinical benefits across diverse patient populations. Figure 1 summarizes the main differences between LPLD and HPSD/vHPSD RF strategies.

Figure 1 Lesion geometry and biophysical mechanisms: Low-power long-duration vs High-power short-duration radiofrequency ablation. LPLD: Low-power long-duration; HPSD: High-power short-duration; RF: Radiofrequency. Adapted from Bourier et al[4] and Leshem et al[7].

ABLATION INDEX/LESION INDEX, IMPEDANCE DROP, AND TEMPERATURE-CONTROLLED RF IN HPSD/VHPSD

Lesion surrogates, such as the ablation index (AI) and lesion size index, were initially developed for conventional RF and integrate variables such as power, contact force, and time to estimate lesion formation. In HPSD, time is intentionally reduced, and heating is more front-loaded, altering the interpretation of traditional time-weighted indices. Therefore, many operators use real-time biophysical feedback, particularly impedance drop and temperature trends, to confirm energy coupling within seconds. Temperature-controlled RF platforms (e.g., QDOT, Biosense Webster) enable very high-power delivery while actively modulating power to maintain a target temperature, helping reduce overheating, steam pops, or charring during 90 W/4 seconds applications. Evidence from vHPSD trials shows that contiguous point placement may improve lesion durability. Where available, personalized dosing (such as left atrial wall thickness-guided strategies) can address thicker regions where ultra-short lesions may be shallower[3,6,12].

EVIDENCE FROM RANDOMIZED CLINICAL TRIALS: EFFICIENCY, EFFICACY, AND SAFETY

Randomized data consistently show procedural efficiency gains with HPSD/vHPSD (shorter RF time and often shorter procedure time), while clinical efficacy at follow-up is generally non-inferior and sometimes improved, depending on protocol and endpoints[9]. In the SHORT-AF randomized trial, HPSD resulted in a shorter time to achieve PVI and greater freedom from AF at 12 months compared to LPLD, but with a trend toward more asymptomatic cerebral emboli on imaging[10]. In POWER-FAST III (HPSD-70 W vs conventional 25-40 W), HPSD-70 W was non-inferior for atrial arrhythmia recurrence, with similar incidence of endoscopically detected esophageal lesions, but the investigators reported symptomatic embolic events (atrial conduction enhancement) associated with the HPSD-70 approach using conventional contact force-sensing catheters not specifically designed for very high power[11]. For vHPSD, QDOT-FAST (first-in-human, single-arm) demonstrated the feasibility and safety of a temperature-controlled catheter/algorithm delivering 90 W/4 seconds lesions with reduced procedure/fluoroscopy times relative to historical point-by-point ablation[6]. In the randomized POWER PLUS trial, contiguous 90 W/4 seconds ablation reduced procedure time modestly but significantly, with 6-month efficacy and safety similar to those of a conventional approach, and the authors suggested that hybrid approaches may be optimal[12]. A further step toward personalization is represented by QDOT-by-LAWT, a randomized non-inferiority trial in which a left atrial wall thickness-guided strategy (vHPSD in thinner regions, standard/AI-guided in thicker regions) achieved non-inferior 12-month effectiveness vs a standard CLOSE protocol while markedly improving procedural efficiency[3]. This study is the first to demonstrate the effectiveness of RF titratability in distinct regions of the LA. Rather than applying uniform energy across varying LA tissue thicknesses, the protocol employed a personalized strategy that combined vHPSD and standard-power RF ablation, tailored to left atrial wall thickness, to achieve PVI. These findings strengthen one of the unique characteristics of the “old men” (RF), its unique titratability. The LAWT-guided QDOT approach retains the distinct advantage of maintaining the flexibility of point-by-point RF ablation tailored to a patient’s specific anatomy.

SAFETY CONSIDERATIONS: ESOPHAGUS, STEAM POPS, AND CEREBRAL EMBOLIC EVENTS

From a biophysical standpoint, reduced conductive heating time might be expected to mitigate esophageal heating. However, randomized controlled trial data do not consistently show a clear reduction in endoscopically detected esophageal lesions[14-16]. A common assumption underlying HPSD ablation is that shortening RF application duration reduces conductive heat transfer and consequently lowers the risk of esophageal collateral injury. While this concept is supported by experimental lesion models, clinical experience suggests that the relationship between power, duration, and esophageal safety is more complex. Although HPSD reduces the time available for conductive heat propagation, higher power delivery also results in more rapid tissue heating and earlier achievement of peak temperatures at the catheter-tissue interface. Consequently, when ablation is performed directly adjacent to the esophagus, particularly along the PW of the LA, tissue temperatures capable of causing transmural injury may be reached within seconds. Therefore, shortening application duration alone does not guarantee protection from esophageal damage. This observation is consistent with randomized studies such as Hi-Lo HEAT[14] and POWER-FAST III[11], in which reductions in RF duration did not translate into a clear reduction in endoscopically detected esophageal lesions compared with conventional RF strategies. An additional source of confusion within the literature is the frequent grouping of HPSD and vHPSD ablation under a single conceptual framework. Conventional HPSD protocols generally employ powers of approximately 45-50 W delivered for 5-15 seconds and rely primarily on irrigation, contact force optimization, and lesion quality metrics to maintain procedural safety. In contrast, contemporary vHPSD protocols typically deliver 90 W for approximately 4 seconds using dedicated catheters equipped with multiple thermocouples and real-time temperature-controlled algorithms. In these systems, power delivery is continuously adjusted according to measured tissue temperature, allowing rapid lesion formation while limiting excessive tissue overheating. Therefore, the safety profile observed with temperature-controlled vHPSD systems cannot be directly extrapolated to non-temperature-controlled HPSD approaches using conventional irrigated catheters. This distinction is particularly relevant when interpreting also other safety outcomes such as steam pops and cerebral embolic events. Although the overall safety profile of HPSD/vHPSD ablation appears comparable to conventional RF ablation in most randomized trials and meta-analyses, embolic safety signals require careful interpretation. In SHORT-AF, HPSD ablation was associated with shorter time to PVI and improved 12-month freedom from AF, but the investigators also reported a trend toward increased asymptomatic acute cerebral embolic events on post-procedural imaging[10]. Similarly, POWER-FAST III demonstrated non-inferior arrhythmia outcomes and comparable rates of endoscopically detected esophageal lesions, yet symptomatic embolic events were observed in the 70-W HPSD arm[11]. These findings do not necessarily indicate a class effect of all HPSD strategies, as embolic risk may be influenced by power setting, catheter design, irrigation characteristics, temperature control, contact force, lesion contiguity, anticoagulation management, and procedural workflow. However, they highlight that procedural efficiency should not be interpreted as equivalent to procedural safety. Rapid tissue heating may increase the risk of microbubble formation, char, coagulum, or steam-related phenomena when energy delivery is not adequately controlled. Therefore, HPSD and especially very-high-power protocols should be applied using technology-specific parameters, strict attention to catheter stability and contact force, real-time impedance and temperature monitoring when available, and meticulous intraprocedural anticoagulation. Further randomized studies with systematic neurological assessment and standardized cerebral imaging protocols are needed to clarify whether these embolic findings represent isolated protocol-dependent signals or a clinically relevant safety limitation of certain HPSD approaches. These trials are summarized in Table 1.

Table 1 Trials and key evidence.

Ref.	Design/population	Strategy/protocol	Key endpoints	Main findings (high level)
QDOT-FAST, 2019[6]	Prospective multicenter single-arm; PAF	vHPSD temperature-controlled (90 W/4 seconds algorithm)	Feasibility, acute performance, safety	Demonstrated feasibility and safety of 90 W/4 seconds temperature-controlled lesions; procedural efficiency vs historical controls
POWER PLUS, 2023[12]	Multicenter RCT; AF undergoing first PVI	Contiguous vHPSD 90 W/4 seconds vs conventional approach	Efficiency; 6-month efficacy; safety	Modest but significant reduction in procedure time; similar safety and 6-month efficacy; suggested hybrid approach may be optimal
SHORT-AF, 2023[10]	RCT; AF ablation with PVI	HPSD vs standard power-standard duration	Time to PVI; 12-month freedom from AF; ACE	Shorter time to PVI; higher freedom from AF at 12 months; trend toward increased ACE
POWER-FAST III, 2025[11]	RCT; PVI with endoscopic assessment	HPSD-70 (70 W, short) vs conventional 25-40 W	Arrhythmia recurrence (noninferiority); endoscopic esophageal lesions	Noninferior for recurrences; similar esophageal lesion incidence; reported symptomatic embolic events in HPSD-70 arm (technology/protocol-dependent signal)
QDOT-by-LAWT, 2024[3]	RCT noninferiority; first-time PAF	LA wall thickness-guided (vHPSD in thinner regions; standard/AI-guided in thicker) vs CLOSE	12-month effectiveness; efficiency	Noninferior 12-month outcomes; marked reductions in RF/procedure times; supports personalization for thicker regions
Sousa et al[9], 2023	RCT; PAF treated with AI	HPSD vs standard LPLD (AI-guided)	Noninferiority; efficiency	Reported noninferiority and faster procedures with shorter ablation times (protocol- and catheter-specific)

RCT: Randomized controlled trial; AF: Atrial fibrillation; PVI: Pulmonary vein isolation; vHPSD: Very high-power short-duration; HPSD: High-power short-duration; ACE: Atrial conduction enhancement; LA: Left atrium; AI: Ablation index; LPLD: Low-power long-duration.

SYNTHESIS FROM META-ANALYSES

A widely cited 2021 systematic review/meta-analysis comparing HPSD with conventional RF reported improved procedural effectiveness (9% higher freedom from atrial arrhythmia compared to conventional power) and shorter procedural duration (driven by shorter LA dwell time and RF ablation time) with comparable overall safety, especially in the context of patients with paroxysmal AF and with the employment of ≥ 50 W protocols and contact force sensing catheters[8]. More recent meta-analyses focusing specifically on randomized trials similarly support shorter procedure/PVI/RF times with HPSD, while generally showing non-inferior clinical outcomes and emphasizing protocol heterogeneity and device differences as key limitations[17,18]. The most reproducible advantage of HPSD/vHPSD is efficiency (shorter RF and procedural times). Clinical effectiveness is generally non-inferior and can be favourable in some datasets. Safety signals, particularly regarding cerebral embolic events and steam pops, appear protocol- and technology-dependent. Meta-analyses are summarized in Table 2.

Table 2 Meta-analyses comparing high-power short-duration/very high-power short-duration vs conventional low-power long-duration radiofrequency ablation.

Ref.	Study type	Included studies (n)/patients (n)	RCT-only vs mixed	Main efficacy findings	Procedural efficiency	Safety findings	Key limitations
Ravi et al[8]	Systematic review and meta-analysis	13 studies/approximately 2900 patients	Mixed (RCT + observational)	Higher freedom from atrial arrhythmia with HPSD in pooled analysis	Significant reduction in procedure time, RF time, and fluoroscopy	No significant difference in major complications overall	Predominantly observational data; heterogeneous power protocols
Parlavecchio et al[18]	Meta-analysis	6 studies/approximately 1100 patients	Mixed	Trend toward improved arrhythmia-free survival with HPSD	Reduced RF and total procedure duration	Similar rates of major complications, including tamponade and stroke	Limited number of RCTs; protocol heterogeneity
Amin et al[17]	Meta-analysis	8 studies/approximately 1500 patients	RCT-focused (majority randomized)	HPSD noninferior to LPLD for arrhythmia recurrence	Significant reduction in RF time and procedural duration	No significant difference in overall complications or esophageal injury	Limited follow-up duration in some included trials

RCT: Randomized controlled trial; HPSD: High-power short-duration; RF: Radiofrequency; LPLD: Low-power long-duration.

HETEROGENEITY AMONG EVIDENCE

One of the major limitations in the current HPSD/vHPSD literature is the substantial heterogeneity among study protocols, which complicates direct comparisons across trials and may partly explain conflicting efficacy and safety findings. Although studies are often grouped under the umbrella term “HPSD” the actual ablation strategies vary considerably. Power settings range from 45-50 W in conventional HPSD protocols to 70 W in studies such as POWER-FAST III and up to 90 W in temperature-controlled vHPSD systems such as QDOT-FAST and POWER PLUS[6,11,12]. Application duration also varies substantially, ranging from approximately 4 seconds with temperature-controlled 90-W systems to 10-15 seconds in conventional HPSD approaches. Important differences also exist in catheter technology. Earlier studies employed standard irrigated contact-force sensing catheters, whereas more recent investigations have used dedicated temperature-controlled platforms capable of real-time thermal feedback and automatic power modulation[4,6,11,12]. These technological differences may substantially influence lesion formation, procedural reproducibility, and the incidence of complications such as steam pops, char formation, and embolic events. Consequently, safety signals observed with one platform cannot necessarily be generalized to all HPSD strategies. Further heterogeneity arises from lesion assessment methodologies. Some studies used AI-guided protocols, others relied on lesion size index, impedance drop, temperature feedback, or operator-dependent endpoints. Inter-lesion spacing, contact-force targets, irrigation settings, esophageal protection strategies, and anticoagulation protocols also differed considerably among trials[3,9,12]. In addition, patient populations were not uniform, with varying proportions of paroxysmal and persistent AF, different left atrial substrate characteristics, and diverse adjunctive lesion sets beyond PVI[3,10-12,14,15]. These differences have important implications for interpreting both efficacy and safety outcomes. Meta-analyses consistently demonstrate reductions in RF and procedural times with HPSD/vHPSD ablation; however, conclusions regarding arrhythmia recurrence, lesion durability, esophageal injury, and cerebral embolic risk should be interpreted cautiously because pooled analyses combine substantially different technologies and treatment strategies[8,17,18]. Future studies should adopt more standardized definitions of HPSD and vHPSD, harmonize lesion-quality metrics and safety endpoints, and report technology-specific outcomes to facilitate meaningful comparisons across studies.

HPSD RF ABLATION FOR PVI

PVI represents the cornerstone of catheter ablation for AF and remains the most widely adopted rhythm-control strategy in patients with symptomatic AF refractory to antiarrhythmic drug therapy[19]. Over the past two decades, major technological advances in catheter design, electroanatomical mapping systems, and lesion assessment tools have substantially improved both the efficacy and safety of RF ablation procedures. Conventional RF ablation strategies typically employ relatively low-to-moderate power settings ranging from 25 W to 35 W delivered for 20-40 seconds per lesion. As previously described, lesion formation during RF ablation occurs through two principal mechanisms: Resistive heating, which occurs immediately at the electrode-tissue interface, and conductive heating, which spreads progressively to deeper myocardial layers over time. Experimental studies have demonstrated that resistive heating typically affects tissue within approximately 1-3 mm from the catheter tip, whereas conductive heating may extend lesion depth to approximately 4-6 mm, depending on contact force and application duration. Although conventional LPLD ablation aims to achieve transmural lesions, prolonged RF delivery increases conductive heat propagation and may expose adjacent structures - particularly the esophagus - to thermal injury. In addition, prolonged RF applications significantly contribute to procedural duration, with cumulative RF delivery time during PVI frequently exceeding 30 minutes in conventional workflows[19].

ROLE OF CONTACT FORCE AND LESION QUALITY METRICS IN LESION DURABILITY

One of the most important technological advances in catheter ablation has been the introduction of contact-force-sensing catheters, which enable real-time assessment of catheter-tissue interaction. Experimental work demonstrated that lesion size and depth strongly correlate with both the magnitude and stability of contact force during RF application[20]. In ex vivo models, lesion depth increased from approximately 3.5 mm at 5 g of contact force to more than 6 mm at 30 g. Subsequent clinical studies confirmed the importance of adequate catheter contact during AF ablation. In the SMART-AF trial, maintaining optimal contact force during at least 80% of RF applications was associated with significantly higher freedom from atrial arrhythmias at 12 months compared with patients with lower contact force stability (81% vs 66%, P = 0.04)[21]. Similarly, the TOCCATA study demonstrated that patients treated with mean contact force values greater than 20 g experienced markedly improved procedural outcomes compared with those treated with lower contact force levels[22]. Furthermore, repeat ablation studies demonstrated that inadequate catheter contact contributes to pulmonary vein reconnection. In the EFFICAS studies, pulmonary vein reconnection sites were strongly associated with insufficient contact force during the initial ablation procedure. Implementation of predefined contact force targets of approximately 10-20 g significantly reduced reconnection rates[23]. To further standardize lesion delivery, composite lesion quality metrics were introduced. The AI integrates contact force, RF power, and application duration into a single quantitative parameter that correlates with lesion depth and volume[24]. AI-guided ablation strategies have been shown to significantly improve lesion contiguity and procedural reproducibility. One of the most widely adopted approaches is the CLOSE protocol, which targets AI values of approximately ≥ 550 on the anterior wall and ≥ 400 on the PW while maintaining inter-lesion distances ≤ 6 mm. In the original CLOSE study, this strategy achieved durable PVI with approximately 80%-85% freedom from atrial arrhythmias at one year, while pulmonary vein reconnection rates during repeat procedures remained below 10%[25]. Despite these advances in lesion quality metrics, overall procedural duration during PVI remains largely driven by cumulative RF delivery time. This limitation has sparked increased interest in alternative energy-delivery strategies that accelerate lesion formation while preserving lesion durability.

BIOPHYSICAL RATIONALE FOR HPSD ABLATION

HPSD ablation has emerged as an alternative strategy designed to optimize RF lesion formation. Rather than relying on prolonged energy delivery, HPSD protocols employ higher RF power - typically 45-50 W - delivered over shorter durations of approximately 5-10 seconds. Experimental studies have demonstrated important differences in lesion geometry between conventional and HPSD ablation strategies. In mechanistic experiments, Leshem et al[7] demonstrated that HPSD applications produce lesions with larger surface diameters but shallower depth than conventional RF applications. Similarly, Bourier et al[4] showed that increasing RF power while shortening application duration results in broader lesion diameters with more limited deep tissue penetration. These lesion characteristics may be particularly advantageous in atrial myocardium, where tissue thickness typically ranges from 1 mm to 4 mm. Wider lesions may improve lesion contiguity and reduce conduction gaps, whereas shallower penetration may reduce the risk of thermal injury to adjacent extracardiac structures, such as the esophagus.

EARLY CLINICAL EXPERIENCE WITH HPSD ABLATION

Early clinical experience suggested that HPSD strategies could significantly improve procedural efficiency while maintaining favorable clinical outcomes. In a cohort study by Kottmaier et al[26], PVI performed using a 50-W HPSD protocol significantly shortened RF delivery time and overall procedure duration while maintaining excellent clinical outcomes. Freedom from atrial arrhythmias at one year was approximately 80%, with low complication rates. Similarly, Winkle et al[16] reported that high-power ablation strategies significantly reduced cumulative RF delivery time while maintaining freedom from AF of approximately 80%-85% at one year in selected patient populations. These early experiences provided proof-of-concept evidence supporting the feasibility and safety of HPSD ablation.

RANDOMIZED CLINICAL TRIALS AND REAL WORLD

Several randomized studies have subsequently compared HPSD with conventional RF ablation strategies. In the randomized study by Lee et al[10], high-power ablation using 50 W significantly reduced PVI time (87 minutes vs 126 minutes, P = 0.003). First-pass PVI rates were similar between groups (79% vs 76%), but freedom from atrial arrhythmias at 12 months was significantly higher in the HPSD group [90% vs 65%, hazard ratio (HR): 0.26, P = 0.027]. The POWER-FAST III trial evaluated an even higher power strategy using 70-W applications and demonstrated a substantial reduction in RF delivery time (11.2 minutes vs 31.0 minutes, -64%, P < 0.001). Procedure duration was modestly reduced. First-pass PVI was lower in the HPSD arm (71% vs 83%, P = 0.02), whereas freedom from atrial arrhythmias at one year was comparable between strategies (67% vs 73.5%, HR: 1.28, P = 0.28)[11]. The Hi-Lo HEAT randomized trial similarly demonstrated that higher-power ablation significantly reduced RF delivery time (23.8 minutes vs 29.7 minutes, P < 0.01) and overall procedure duration (133 minutes vs 150 minutes, P = 0.05). Freedom from atrial arrhythmias favored the high-power strategy (84% vs 66%, HR: 0.42, P = 0.04), while oesophageal thermal injury occurred in approximately 4%-5% of patients in both groups[14]. More recently, vHPSD ablation has been introduced. In a randomized trial, O’Neill et al[12] evaluated temperature-controlled 90-W applications delivered for approximately 4 seconds. RF delivery time was dramatically reduced (4.5 minutes vs 15.4 minutes, -71%, P < 0.0001), and first-pass PVI was significantly higher (74.9% vs 56.4%, P = 0.0005). Freedom from atrial arrhythmias at one year was similar between groups (78.1% vs 82.3%), while serious complications occurred in 1.9% vs 3.1% of patients. Registry data further support the feasibility and safety of HPSD ablation. The multicenter peQasus registry, including more than 1000 patients, reported acute PVI in 100% of procedures, with first-pass isolation achieved in approximately 64% of patients. Freedom from atrial arrhythmias at one year was 77%, while severe complications occurred in only 1.7% of patients[27].

EVIDENCE FROM META-ANALYSES

The growing body of evidence on HPSD ablation has been summarized in several meta-analyses. Kumar et al[28] performed a systematic review and meta-analysis including 21 studies and 4169 patients, demonstrating that HPSD RF ablation was associated with a significant reduction in atrial tachyarrhythmia recurrence at 1 year compared with conventional LPLD ablation [risk ratio (RR): 0.62, 95%CI: 0.50-0.78; P = 0.00001; I² = 0%]. A trend toward lower AF recurrence was also observed (RR: 0.64, 95%CI: 0.40-1.01; P = 0.06). Furthermore, HPSD significantly increased first-pass PVI (RR: 1.19, 95%CI: 1.08-1.30; P = 0.0003) and reduced acute pulmonary vein reconnection (RR: 0.57, 95%CI: 0.45-0.73; P < 0.00001). These improvements in lesion durability translated into substantial procedural advantages, including a mean reduction in total procedural time of 35.6 minutes and a reduction in fluoroscopy time of 3.16 minutes. Similarly, Jin et al[29] conducted a systematic review and meta-analysis including 17 studies and 4934 patients, demonstrating that HPSD ablation significantly improved freedom from atrial arrhythmia at one year compared with conventional strategies (OR: 1.48, 95%CI: 1.12-1.94; P = 0.005). HPSD was also associated with higher first-pass PVI (OR: 8.92; P < 0.001) and lower acute pulmonary vein reconnection (OR: 0.40; P < 0.001). Procedural efficiency was significantly enhanced, with reductions in procedure duration, RF delivery time, and fluoroscopy exposure, while complication rates remained comparable between strategies. Parlavecchio et al[18] performed a meta-analysis of randomized trials including five studies and 424 patients, demonstrating that HPSD ablation was associated with significantly lower AF recurrence compared with conventional ablation (16.3% vs 30.1%; RR: 0.54, 95%CI: 0.38-0.79; P = 0.001) at a mean follow-up of 10.9 months. HPSD also significantly reduced total procedure time, PVI time, RF application time, and the number of RF lesions delivered, without increasing complication rates. Collectively, these data suggest that HPSD ablation improves both procedural efficiency and lesion durability, likely reflecting the predominance of resistive heating and the generation of broader and more contiguous lesions.

CLINICAL AND PROCEDURAL IMPLICATIONS OF HPSD ABLATION

Taken together, the available evidence indicates that HPSD ablation improves procedural efficiency while maintaining comparable safety and rhythm outcomes compared with conventional RF ablation strategies. Across randomized trials and meta-analyses, HPSD consistently reduces RF delivery time and overall procedural duration, with reductions in procedure time ranging from approximately 25 minutes to 40 minutes across pooled analyses[18,28,29]. These procedural advantages likely reflect the ability to create contiguous lesions more rapidly, thereby reducing catheter instability and minimizing the risk of conduction gaps along the ablation line. Importantly, major complication rates remain low and comparable between strategies across studies, indicating that improvements in procedural efficiency are achieved without compromising procedural safety[18,28,29]. Future investigations will be essential to better define the optimal balance between RF power and application duration and to clarify the role of emerging technologies - such as PFA - within the evolving landscape of AF ablation.

HPSD ABLATION FOR PW ISOLATION

HPSD and vHPSD RF strategies have recently been investigated as potential approaches to optimize lesion formation during left atrial posterior wall (PW) ablation and isolation. Compared with conventional LPLD RF delivery, HPSD ablation (typically 40-50 W for 5-10 second) produces lesions predominantly driven by resistive heating, resulting in wider but relatively shallow lesions. This lesion geometry may be particularly advantageous on the PW, where the atrial myocardium is thin and highly heterogeneous, and where conduction gaps frequently occur after conventional lesion sets due to anisotropic fiber orientation and epicardial connections. Consequently, the application of HPSD strategies may facilitate the creation of contiguous and transmural lesion sets while reducing total ablation time[4]. Evidence specifically addressing PW ablation with HPSD remains limited but is progressively emerging. The strongest randomized evidence currently available comes from the Hi-Lo HEAT trial, a prospective multicenter randomized study evaluating HPSD vs LPLD RF delivery during PW ablation in patients undergoing AF ablation. In this trial, 88 patients were randomized to HPSD (40 W) or LPLD (25 W) PW lesion delivery. The primary endpoint - endoscopically detected esophageal thermal injury - occurred in 4.5% of patients overall, with no significant difference between groups (P = 1.0). Importantly, HPSD significantly reduced procedural metrics, including RF delivery time (23.8 minutes vs 29.7 minutes, P < 0.01), PVI duration (46.5 minutes vs 59 minutes, P = 0.01), and total procedure time (133 minutes vs 150 minutes, P = 0.05). At a median follow-up of 12 months, AF recurrence occurred in 15.9% of patients in the HPSD group vs 34.1% in the LPLD group, corresponding to a HR of 0.42 (log-rank P = 0.04). These findings suggest that HPSD PW ablation may improve procedural efficiency while maintaining comparable esophageal safety and potentially improving arrhythmia outcomes[14].

Observational studies have provided additional insights into the feasibility and durability of HPSD-guided PW isolation (PWI). In a retrospective cohort study evaluating lesion index-guided HPSD PW ablation in persistent AF, PWI was achieved in 100% of cases, with first-pass roofline block in 88.5% of patients and first-pass inferior line block in 51.4%, highlighting the technical challenges associated with achieving durable inferior line conduction block even with high-power strategies[30]. In a subsequent prospective study using the contact-force sensing TactiFlex catheter, PWI was again achieved in all patients, with only two PW reconnections observed during follow-up, and significantly shorter procedural metrics compared with a historical HPSD cohort (procedure time 73.1 ± 12.6 minutes vs 98.5 ± 16.3 minutes, P < 0.001; RF time 11.3 ± 1.5 minutes vs 23.5 ± 3.6 minutes, P < 0.001). Notably, no catheter-related intra-procedural complications were reported[31]. The introduction of vHPSD technology has further accelerated lesion creation during PW ablation. In a comparative study evaluating vHPSD vs conventional power ablation for PVI combined with PW ablation in persistent AF, acute procedural efficacy favored vHPSD, with PVI achieved in 98% of cases compared with 75% using standard-power ablation (P = 0.007). During a median follow-up of 18 months, survival free from recurrent atrial tachyarrhythmias was 68% in the vHPSD group vs 47% in the conventional ablation group (log-rank P = 0.071), while multivariable analysis demonstrated that vHPSD ablation was independently associated with a reduced risk of AF recurrence (HR: 0.39, P = 0.030)[32].

Despite these promising results, applying high-power strategies to the PW raises important safety concerns regarding esophageal injury, given the anatomical proximity between the esophagus and the PW of the LA. A recent investigation focusing specifically on PW ablation adjacent to the esophagus demonstrated that the use of vHPSD reduced both total application time and delivered energy (both P < 0.001) and decreased the incidence of luminal esophageal temperature elevations ≥ 40 °C (P = 0.036). However, these safety advantages were accompanied by a higher rate of PW reconnection near the esophagus (11.9% vs 3.6%, P = 0.046), highlighting the delicate balance between lesion durability and esophageal protection in this region[33].

Overall, current evidence suggests that HPSD and vHPSD strategies for PW ablation can significantly improve procedural efficiency while maintaining an acceptable safety profile, particularly when strict lesion-quality targets and esophageal protection strategies are implemented. However, the evidence base remains limited, consisting of a single randomized trial and several observational studies, and further large-scale randomized trials specifically addressing PWI using high-power strategies are required to determine whether these approaches consistently translate into improved long-term arrhythmia-free survival in patients with persistent AF.

HPSD AND MI ABLATION

Compared with PVI, PWI, and cavotricuspid isthmus (CTI) ablation, the evidence supporting HPSD RF ablation for MI line creation is considerably more limited. Available data are derived primarily from small observational studies, registry experiences, and isolated case reports, with no dedicated randomized controlled trials specifically evaluating HPSD strategies for MI ablation. Consequently, current evidence is insufficient to determine whether HPSD offers meaningful advantages over conventional RF approaches in achieving durable bidirectional MI block or reducing arrhythmia recurrence. Only a small number of observational studies and case reports have described the application of HPSD strategies for mitral-dependent circuits. In a comparative study evaluating HPSD ablation (45-50 W) vs conventional LPLD RF strategies during AF ablation procedures, additional linear lesions, including mitral annular lines, were permitted. HPSD demonstrated procedural feasibility for MI ablation while significantly reducing total RF delivery time (17.2 ± 3.4 minutes vs 31.1 ± 5.6 minutes; P < 0.001), with similar acute success and complication rates between the two approaches[5]. More direct evidence derives from studies evaluating temperature-controlled HPSD ablation systems such as the DiamondTemp catheter. In these series, RF energy was typically delivered using temperature-controlled applications at powers of 45-50 W with application durations of approximately 5-10 seconds per lesion. Acute bidirectional conduction block across the MI was achieved in approximately 70%-80% of patients. However, complementary epicardial ablation within the coronary sinus was required in roughly 50%-60% of procedures to achieve durable conduction block, reflecting the well-recognized anatomical complexity of the region[34]. Additional support comes from a case report describing perimitral macroreentrant atrial tachycardia treated with very-high-power, short-duration ablation (90 W, 4 seconds) using a QDOT Micro catheter. In that case, electroanatomical activation mapping demonstrated a macro-reentrant circuit involving the anterior left atrial wall adjacent to the mitral annulus with a tachycardia cycle length of approximately 270 milliseconds. Entrainment mapping confirmed the presence of a critical isthmus within the anterior peri-mitral region. Progressive prolongation of the tachycardia cycle length was observed during ablation, followed by tachycardia termination after the tenth RF application. Completion of the anterior linear lesion required a total of 29 applications, corresponding to a cumulative RF time of 116 seconds. Bidirectional conduction block across the line was subsequently confirmed using differential pacing and activation mapping, and no procedural complications were reported[35].

Despite these initial observations, achieving a durable bidirectional block across the MI remains technically challenging. Anatomical studies have shown that the atrial wall thickness in the MI region typically ranges between 4 mm and 6 mm, and the presence of epicardial connections through the coronary sinus musculature often limits the effectiveness of endocardial ablation alone. Consequently, epicardial ablation from within the coronary sinus is frequently required to interrupt residual conduction across the MI. Previous studies have reported acute bidirectional block rates of approximately 60%-80%, while reconnection of the MI line has been observed in up to 30%-50% of patients undergoing repeat procedures. From a biophysical perspective, lesions generated by HPSD ablation are characterized by predominantly resistive heating, resulting in wider but shallower lesions compared with those produced by conventional RF applications. While this lesion geometry may facilitate contiguous lesion formation in thin atrial tissue, it may be less favorable in regions such as the MI, where deeper and more transmural lesions are often required to interrupt epicardial conduction pathways[36]. Consequently, although HPSD strategies are increasingly adopted during AF ablation procedures, specific evidence supporting their superiority for MI ablation remains scarce, and dedicated prospective studies are required.

HPSD ABLATION FOR CTI ABLATION

In contrast to PVI, the evidence supporting HPSD RF ablation for CTI ablation remains limited, and no dedicated meta-analysis specifically addressing contemporary HPSD strategies for CTI lesions is currently available. The only CTI-focused meta-analysis in the literature is the study of Da Costa et al[37], which pooled seven randomized trials including 603 patients and compared cooled-tip and 8-mm-tip catheters, demonstrating no significant differences in bidirectional CTI block (RR: 0.96, 95%CI: 0.92-1.01; P = 0.13), RF application time [weighted mean difference (WMD): 0.88 minutes, 95%CI: -0.36 to 2.12; P = 0.16], fluoroscopy duration (WMD: 1.07 minutes, 95%CI: -0.81 to 2.95; P = 0.26), or procedural duration (WMD: 0.68 minutes, 95%CI: -3.37 to 4.73; P = 0.74). From a mechanistic perspective, the CTI represents a particularly favorable substrate for HPSD ablation. The CTI typically consists of relatively thin atrial myocardium (approximately 3-5 mm), and ablation targets a linear conduction pathway between the tricuspid annulus and inferior vena cava. Experimental and clinical studies have demonstrated that high-power delivery predominantly generates resistive heating, with limited conductive heat propagation, resulting in wider, more homogeneous lesions that may facilitate rapid transmural lesion formation across thin atrial structures such as the CTI[4]. Consistent with this biophysical rationale, several contemporary studies have demonstrated improved procedural efficiency with HPSD CTI ablation. In a prospective cohort study including 84 patients, Kwon et al[38] compared a 50 W for 15 seconds strategy with conventional 30 W for 60 seconds applications and reported significantly shorter RF delivery time with HPSD (236 ± 85.6 seconds vs 534.2 ± 235.2 seconds; P < 0.001), while bidirectional CTI block was achieved in nearly all patients in both groups and recurrence rates remained low during follow-up. Similarly, Golian et al[39] evaluated 114 consecutive patients and demonstrated that HPSD ablation was independently associated with a 66% reduction in RF delivery time (95%CI: 58%-73%). Acute bidirectional block was achieved in all procedures, while recurrent typical flutter occurred in 0% of HPSD patients compared with 7% in the conventional group (P = 0.057). Further refinement has been achieved with AI-guided strategies. In a prospective study of 52 patients, Tscholl et al[40] reported acute CTI block in 100% of procedures, with first-pass block in 80.4% and only one case of spontaneous reconduction after a 30-minute waiting period. The randomized trial by Chikata et al[41] currently provides the strongest comparative evidence. In 130 patients undergoing AI-guided CTI ablation, a 45 W strategy achieved significantly higher first-pass block compared with 35 W (93.8% vs 76.9%, P = 0.01) and significantly reduced CTI ablation time (192.3 ± 84.8 seconds vs 319.8 ± 171.4 seconds; P < 0.0001) and fluoroscopy time (125.2 ± 122.4 seconds vs 171.2 ± 124.0 seconds; P = 0.039), without an increase in major complications. More recently, vHPSD strategies have been investigated for CTI ablation. In the prospective study by Schillaci et al[42], CTI ablation using 90 W-4 seconds achieved first-pass bidirectional block in 89% of patients, with efficacy comparable to AI-guided ablation (89% vs 93%, P = 0.59) but with markedly shorter RF delivery time (88 ± 40 seconds vs 492 ± 269 seconds, P < 0.001). Overall, available studies consistently suggest that HPSD and vHPSD strategies significantly improve procedural efficiency during CTI ablation while maintaining high acute success rates and favorable short-term outcomes. However, the evidence base remains limited to relatively small prospective studies and a single randomized comparison, and larger multicenter randomized trials are required to establish the optimal ablation strategy for CTI lesions.

HPSD RF ABLATION IN THE ERA OF PFA

The recent introduction of PFA has generated considerable enthusiasm due to its non-thermal mechanism of action and its potential for tissue selectivity, particularly with regard to myocardial cells while sparing surrounding structures such as the esophagus and phrenic nerve[43]. Early clinical trials and registries have demonstrated high acute success rates, favorable safety profiles, and shorter procedural times with PFA compared with conventional ablation strategies[44-47]. These findings have led many to speculate whether thermal energy sources, including RF ablation, may eventually be replaced in AF ablation workflows.

However, PFA remains a relatively new technology and long-term clinical experience is still limited compared with RF ablation. As clinical use expands, several complications have been reported, including myocardial ischemia related to coronary vasospasm[48], malignant ventricular arrhythmias[48], endothelial disruption[49], hemolysis[50-52], vasovagal response[52], and cerebrovascular ischemic lesions[53,54]. These events appear to be uncommon and should be interpreted within the context of the technology’s unique advantages: Tissue selectivity with reduced collateral injury to adjacent structures, relative independence on contact force and on prolonged catheter stability. However, the safety profile of electroporation continues to evolve and requires further investigation in larger and longer-term studies.

On the other hand, current evidence suggests that HPSD RF ablation remains a highly effective and mature technology with several enduring advantages. First, HPSD ablation is supported by a substantial body of experimental, clinical, and randomized evidence demonstrating reliable lesion formation, durable PVI, and favorable long-term rhythm outcomes. Second, the biophysical principles underlying HPSD, predominantly resistive heating with limited conductive spread, enable rapid lesion formation with predictable lesion geometry and reduced procedural duration. Third, contemporary catheter technologies incorporating contact force sensing, lesion quality metrics, and temperature-controlled energy delivery have further improved the reproducibility and safety of RF lesion creation[20-25]. Fourth, while PFA offers tissue selectivity and procedural reproducibility, HPSD RF ablation retains unique advantages related to point-by-point lesion titration and anatomical customization[3], particularly in complex substrates and redo procedures. Last but not least, fluoroscopy time resulted to be shorter with HPSD compared with PFA, with clear benefits for patients and cath lab operators[46,47,55].

Recent meta-analyses comparing PFA with HPSD or vHPSD RF ablation suggest that although PFA may offer shorter procedural times and potentially favorable safety profiles, clinical efficacy and arrhythmia-free survival appear largely comparable between the two approaches[46,47,56-58]. Importantly, HPSD ablation remains widely available, technologically mature, and supported by extensive operator experience across a broad range of clinical scenarios. Rather than representing competing technologies, PFA and HPSD RF ablation may ultimately prove complementary, with energy selection tailored to anatomical substrate, operator expertise, and procedural goals. Table 3 summarizes all characteristics of PFA and HPSD RF ablation.

Table 3 Comparison between high-power short-duration/very high-power short-duration radiofrequency ablation and pulsed-field ablation for atrial fibrillation.

Characteristic	HPSD/vHPSD RF ablation	Pulsed-field ablation
Mechanism of action	Thermal injury through resistive and conductive heating	Non-thermal irreversible electroporation
Lesion formation	Wider, relatively shallower lesions; still dependent on tissue heating	Tissue-selective myocardial ablation
Procedural efficiency	Significant reduction in RF and procedure time compared with conventional RF	Generally among the shortest procedure times reported
Pulmonary vein isolation success	Excellent acute success (> 95% in most contemporary studies)	Excellent acute success (> 95%)
Freedom from AF recurrence	Non-inferior or improved compared with conventional RF	Comparable to HPSD/vHPSD in available comparative studies
Esophageal injury	Reduced compared with conventional RF but not eliminated	Very low incidence; major theoretical and clinical advantage
Phrenic nerve injury	Possible, particularly with right-sided lesions	Generally reduced due to tissue selectivity
Steam pops	Potential risk, especially at very high power	Not applicable
Cerebral embolic events	Reported in some HPSD trials (e.g., SHORT-AF, POWER-FAST III)	Cerebral lesions reported in some studies; long-term significance uncertain
Dependence on contact force and catheter stability	High	Lower
Operator dependence	Moderate to high	Potentially lower
Long-term evidence	Extensive clinical experience and long-term follow-up	Growing but still limited long-term experience
Technology maturity	Well established and widely available	Emerging and rapidly expanding
Current limitations	Thermal injury, protocol heterogeneity, operator dependence	Limited long-term data, evolving safety profile, device-specific learning curve

vHPSD: Very high-power short-duration; HPSD: High-power short-duration; RF: Radiofrequency; AF: Atrial fibrillation.

CONCLUSION

In this evolving landscape, HPSD RF ablation continues to represent a highly relevant and efficient strategy for PVI, even as novel non-thermal technologies such as electroporation enter routine clinical practice. In the era of PFA, HPSD RF ablation should therefore be viewed not as a technology being replaced, but rather as a mature and efficient strategy that will likely coexist with emerging non-thermal ablation modalities.