Pulsed-field ablation versus thermal ablation for atrial fibrillation: A meta-analysis

First Experience Using a Novel Variable Loop Catheter for Mapping and Pulsed Field Ablation of Atrial Fibrillation

BACKGROUND AND AIMS

A novel multielectrode variable loop catheter (VLC) has been introduced for atrial fibrillation (AF) ablation enabling 3D electroanatomic mapping and concomitant pulsed field ablation (PFA). This study sought to investigate the VLC under routine clinical conditions for AF ablation.

METHODS

Consecutive patients with symptomatic AF undergoing first-time AF ablation were prospectively enrolled. All procedures were carried out using the VLC. Electroanatomic mapping pre and post-ablation was conducted with the VLC and a high-density multipolar mapping catheter. The general ablation protocol consisted of four ablation pulses per pulmonary vein (PV). All procedures were conducted in conscious sedation.

RESULTS

Forty-five patients (mean age 66.3 ± 6.1 years, 68.9% paroxysmal AF) were analyzed. Procedure duration was 66.3 ± 13.1 min. Acute pulmonary vein isolation (PVI) was achieved in 45 patients without periprocedural complications. Remapping after the initial 16 ablation pulses revealed sustained electrical conduction to at least one PV in six patients (13.3%). Repeat ablation was conducted and with an average of 7.5 ± 4.5 additional pulses. PV intubation during mapping was achieved in 168/180 PVs with the VLC (93.3%) and in 180/180PVs (100%) with the high-density mapping catheter (p < 0.001). Incomplete PV intubation during mapping did not result in incomplete PVI, as demonstrated by remapping utilizing the high-density mapping catheter. Adequate correlation between left atrial post-ablation remapping of low voltage areas and ablated regions was demonstrated in all patients.

CONCLUSION

PFA-guided AF ablation using the novel VLC is safe and effective. The integration into a 3D-electroanatomic mapping system enables adequate mapping during PFA procedures.

Comparing efficacy and safety between pulsed field ablation, cryoballoon ablation and high-power short duration radiofrequency ablation in atrial fibrillation: a systematic review and network meta-analysis

BACKGROUND

Pulsed field ablation (PFA) and high-power short-duration radiofrequency ablation (HPSD) are emerging techniques for treating atrial fibrillation (AF), offering promising results compared to cryoballoon ablation (CBA). This network meta-analysis aims to evaluates the efficacy and safety of PFA, HPSD, and CBA.

METHOD

PubMed, Scopus and Cochrane Central Register of Controlled Trials were systematically searched for relevant studies until October 2024. The primary outcome is freedom from atrial arrhythmia. A random-effects model was used for data synthesis, and P-scores were employed for outcome ranking. Point estimation (odd ratios) was calculated for comparisons.

RESULTS

Eighteen studies were included in our network meta-analysis, involving 7,071 atrial fibrillation patients. Among them, 2,023 (29%), 3,725 (53%), and 1,323 (18%) patients underwent PFA, CBA, and HPSD, respectively. PFA demonstrated a higher freedom from atrial arrhythmia, with an odds ratio (OR) of 3.63 (95% CI: 2.95-4.46) compared to CBA and 1.89 (95% CI: 1.47-2.43) compared to HPSD. However, PFA was associated with a higher risk of complications (OR = 6.54, 95% CI: 2.13-20.00) compared to CBA, while HPSD showed an insignificant association with a lower risk of complications compared to CBA (OR = 0.61, 95% CI: 0.15-2.42). PFA had the shortest procedural time (P-score: 100%), while HPSD had the longest (P-score: 0%). In contrast, HPSD had the shortest fluoroscopic time, with P-scores of 100%, 46%, and 3% for HPSD, PFA, and CBA, respectively.

CONCLUSION

PFA demonstrated higher efficacy but also a higher risk of complications compared to HPSD and CBA. HPSD showed greater efficacy with comparable safety to CBA.

Combined Catheter Ablation and Left Atrial Appendage Occlusion in Atrial Fibrillation: From Data to Clinical Reality

PURPOSE

Atrial fibrillation (AF) requires treatment that focuses on two main goals: symptom control and prevention of thromboembolic events. Catheter ablation and left atrial appendage occlusion (LAAO) constitute two well-established treatment methods in selected patients that accomplish these two goals correspondingly. Recently, there is increasing interest in performing the two procedures concomitantly in a so-called "combined" or "one-stop" procedure. This review aims to summarize the current data on the combined procedure, from the rationale and the techniques to its clinical efficacy, indications and future directions.

METHODS

An extensive search has been conducted using the MEDLINE/PubMed database to identify the relevant studies.

RESULTS

The reported success rates of the combined procedure are very high and frequently reach 100% when performed by experienced operators. The periprocedural and follow-up complications are low, the procedure is cost-effective, while there is significant stroke, bleeding and arrhythmia incidence reduction that does not seem to be undermined by interference between the two interventions. There are also a few indications that the one-stop procedure has a positive effect on left atrial mechanical function as it has been correlated with left atrial reverse remodeling. On the other hand, some studies suggest possible increase in peri-device leaks (PDLs), compared with LAAO alone, which could in turn negatively affect the clinical outcomes. Most available studies are small and observational, with a lack of randomized controlled trials.

CONCLUSION

Catheter ablation and left atrial appendage occlusion can be safely and effectively combined in a cost-effective single procedure in carefully selected patients.

Pulsed-field ablation versus radiofrequency or cryoballoon thermal ablation in atrial fibrillation: a systematic review and meta-analysis

This review investigated efficacy and safety of pulsed-field ablation (PFA) in comparison with radiofrequency ablation (RFA), cryoballoon ablation (CBA), or both combined. The Odds ratio (OR) and mean difference (MD) with 95% confidence interval (95% CI) were computed. PFA allowed shorter procedure (MD -44.27 minutes, 95% CI: -63.61; -24.93) and left atrium (LA) dwell (MD -32.71 minutes (95% CI: -58.64; -6.78) times, but with longer fluoroscopy time than RFA (MD 8.54 minutes, 95% CI: 4.03; 13.04). Post-procedural complications rate was lower with PFA than CBA (OR 0.53, 95% CI: 0.35, 0.80). Atrial arrhythmias recurrence rate within one year of follow-up was lower with PFA than RFA (OR 0.68, 95% CI; 0.53; 0.87) and CBA (OR 0.69, 95% CI: 0.48; 0.97). PFA allowed shorter procedure and LA dwell times, as well as lower atrial arrhythmia recurrence than RFA and lower post-procedural complications and atrial arrhythmias recurrence rates than CBA.

Pulsed Field Versus High-Power Short-Duration Radiofrequency Ablation in Atrial Fibrillation: A Meta-Analysis

BACKGROUND

Atrial fibrillation, which has increased in prevalence by 33% over the past two decades, affects 59 million people worldwide. It is treated using thermal and nonthermal techniques like radiofrequency, cryoballoon, laser, and pulsed-field ablation (PFA). This meta-analysis is the first to compare PFA with high-power short-duration radiofrequency ablation (HPSD-RFA).

METHODS

We comprehensively searched PubMed, Cochrane Central, and ScienceDirect from inception to August 2024. In Review Manager 5.4.1, we pooled risk ratios (RRs) and weighted mean difference (WMD) along with 95% confidence intervals for dichotomous and continuous outcomes, respectively, and employed a random effects model. Study quality was assessed via the Newcastle-Ottawa Scale, and funnel plots were used to evaluate the risk of publication bias.

RESULTS

Seven studies with a total of 1538 patients were analyzed in this meta-analysis. PFA was associated with a shorter total procedural time (MD = -36.39 min; 95% CI: [-46.23, -26.55]; p < 0.00001; I2 = 90%), left atrial dwell time (MD = -33.22 min; 95% CI: [-53.21, -13.23]; p = 0.001; I2 = 93%), and a longer fluoroscopy time compared to the HPSD-RFA (MD = 9.06 min; 95% CI: [6.13, 11.99]; p < 0.00001; I2 = 96%). Other outcomes were comparable between the two arms.

CONCLUSION

PFA outperforms HPSD ablation in terms of procedural efficiency outcomes except for the total fluoroscopy time. Still, both techniques are comparable regarding safety and arrhythmia control outcomes.

Hemolysis after pulsed-field ablation of atrial fibrillation

Pulsed-field ablation (PFA) offers notable advantages in atrial fibrillation (AF) ablation by selectively targeting cardiomyocytes via an irreversible electroporation mechanism, thereby minimizing damage to surrounding tissues. Although clinical studies demonstrate that PFA is both safe and effective, PFA-mediated hemolysis and potential acute kidney injury (AKI) have been recently reported. This study comprehensively reviews the literature on PFA-associated hemolysis, analyzing the underlying mechanisms, risk factors, and preventive management strategies. In addition, the review discusses approaches to minimize the risk of PFA-induced hemolysis and AKI while offering insights for improving PFA-associated techniques.

Pulsed-field ablation to isolate common inferior pulmonary veins in a patient with recurrent atrial fibrillation

This is the first report of a successful isolation of the common trunk of inferior pulmonary veins (PV) using pulsed-field ablation (PFA). PFA is easier and more reliable than conventional ablation methods for ablation in patients with PV anomalies and/or a small left atrium and for extensive ablation such as box isolation.

Optimized workflow for paroxysmal atrial fibrillation ablation using very high power short duration

Background

wide antral pulmonary vein isolation (PVI) is effective for treating paroxysmal atrial fibrillation (PAF), although time-demanding. We investigated the impact of a standardized ablation protocol by using a bidirectional transeptal steerable sheath, high-density mapping and very high-power-short-duration (vHPSD) catheters on procedure timing, efficacy, and safety.

Methods

consecutive PAF patients free from previous ablations undergoing PVI alone between January 2022 and March 2023 were prospectively enrolled. The standardized workflow included general anesthesia, a single transeptal puncture trough with a bidirectional, steerable visualizable sheath introduced into the left atrium accommodated a high density, penta-spline mapping catheter and a contact force sensor ablation catheter enabled to deliver vHPSD. Procedural data and electrophysiology (EP) laboratory times were systematically collected and analyzed. The primary endpoint was any AF or atrial tachycardia recurrence at 12 and 24 month follow up.

Results

the study cohort was composed by 138 patients (mean age was 59 ± 11 years, 38% female) and successful PVI was achieved in 100% of cases. Overall, first pass isolation (PFI) was 93%, with a LA dwell time of 32 ± 4 min. Significant complications were reported in 3% of patients. Skin-to-skin time and total EP laboratory time were 58 ± 5 min and 85 ± 7 min, respectively. The primary endpoint was achieved by 9% and 12% of cases at 12 and 24 month follow up, respectively. Upper limit skin-to-skin time and missed FPI resulted predictors of the primary endpoint.

Conclusion

This standardized workflow resulted in low procedural times and arrhythmias recurrence without compromising the safety.

Catheter ablation using pulsed-field energy: Advantages and limitations compared with conventional energy

Atrial fibrillation (AF) poses significant risks of heart failure and stroke, emphasizing effective treatment. Catheter ablation using thermal energy sources, such as radiofrequency or cryoballoon ablation, has shown greater success in maintaining sinus rhythm compared with drug therapy. However, thermal ablation (TA) is associated with serious complications, such as atrial-esophageal fistula, phrenic nerve palsy, and pulmonary vein stenosis. Pulsed-field ablation (PFA) is an emerging ablation energy source that uses electroporation to selectively target cardiac tissue while sparing adjacent structures such as nerves and blood vessels. Two randomized controlled trials have demonstrated that PFA is comparable to TA in both efficacy and safety at a 1-year follow-up and had shorter procedure times. A review of six meta-analyses consistently showed shorter procedural times for PFA across all studies. Additionally, three out of the four recent studies with large samples reported lower recurrence rates with PFA. Regarding complication rates, four out of four studies showed lower incidences of phrenic nerve injury with PFA, and two out of three studies reported lower rates of esophageal injury with PFA. However, four out of four studies indicated higher incidences of cardiac tamponade with PFA, highlighting the need for caution among early-career operators. Furthermore, careful monitoring is required considering the possible unforeseen complications specific to PFA and the lack of long-term follow-up data. Despite these concerns, PFA shows promise as a safer, more effective, and efficient alternative to TA for AF, particularly as operator experience and device technology continue to advance.

Temperature-controlled Ablation Versus Conventional Ablation for Pulmonary Vein Isolation in the Treatment of AF: A Systematic Review and Meta-Analysis

Background

This study compared the efficacy and safety of temperature-controlled and conventional contact-force-sensing radiofrequency ablation catheters for pulmonary vein isolation (PVI) in AF.

Methods

Seven studies (1,138 patients) were included. Randomised controlled trials and observational (single-arm and two-arm) studies that reported freedom from AF ≥3 months after PVI with temperature-controlled radiofrequency ablation catheters (Biosense Webster QDOT MICRO operating in QMODE or Medtronic DiamondTemp) were included.

Results

Freedom from AF at a mean (± SD) follow-up of 9.0 ± 3.6 months did not differ significantly between temperature-controlled and conventional ablation (OR 1.22; 95% CI [-0.79, 1.64]; p=0.24). Total procedure duration (-13.5 minutes; 95% CI [-17.1, -10.0 minutes]; p<0.001) and total ablation duration (-8.9 min; 95% CI [-10.3, -7.5 min]; p<0.01) were significantly shorter for temperature-controlled ablation. There were no significant differences between temperature-controlled and conventional ablation in either the aggregated rates of procedural complications (OR 0.69; 95% CI [-0.15, 1.54]; p=0.11) or in the rate of any individual complication.

Conclusion

Temperature-controlled ablation was found to be at least non-inferior to conventional ablation in all measures of efficacy and safety. Further randomised controlled trials are warranted to evaluate long-term rates of freedom from AF and patient comfort.

Clinical importance of tissue proximity indication during pulsed field ablation for atrial fibrillation: insights from initial experience

BACKGROUND

Pulsed field ablation (PFA) for paroxysmal atrial fibrillation (AF) has been gaining worldwide acceptance because of its efficacy and safety. A variable loop circular catheter (VLCC, VARIPULSE, Biosense Webster, Inc) for PFA recently launched in Japan, includes a tissue proximity indication (TPI) feature to monitor catheter-tissue contact via impedance. However, the role of TPI during pulmonary vein isolation (PVI) is unclear.

OBJECTIVE

This study aims to evaluate TPI feasibility during PVI and its relationship with acute pulmonary vein (PV) reconnection.

METHODS

Twenty-one patients with paroxysmal AF underwent PFA (at least 4 ablations per PV) using the VLCC. We evaluated the association between TPI-positive site percentages, voltage, left atrial wall thickness on ADAS 3D software (Adas3D Medical SL, Barcelona Spain), and acute PVI failure sites.

RESULTS

Four of 21 patients (8 failure sites) experienced PVI failure after primary PFA. Failure sites had significantly lower TPI-positive site percentages (0 ± 0% vs 63 ± 27%, P < .001) and higher voltage (3.57 ± 1.35 mV vs 2.06 ± 1.42 mV, P = .003) but not PV wall thickness. We found that a left atrial bipolar voltage amplitude ≥2.24 mV was determinants of PV gaps with an area under the curve of 0.83 calculating receiver operating characteristic curves. TPI-positive site percentages increased significantly (58 ± 29% to 64 ± 26%, P = .009), whereas PV gaps decreased from 3 of 28 PVs (11%) to 2 of 54 PVs (4%, P = .332) between the first 7 and last 14 cases.

CONCLUSION

Acute PVI failure was significantly associated with poor tissue contact and higher voltage. However, acute PVI failure can be prevented with improved TPI-based contact information.

"Form follows function": the developmental morphology of the cardiac atria

Although the heart atria have a lesser functional importance than the ventricles, atria play an important role in the pathophysiology of heart failure and supraventricular arrhythmias, particularly atrial fibrillation. In addition, knowledge of atrial morphology recently became more relevant as cardiac electrophysiology and interventional procedures in the atria gained an increasingly significant role in the clinical management of patients with heart disease. The atrial chambers are thin-walled, and several vessels enter at the level of the atria. The left and right atrium have different structures and shape. In general, both atrial chambers have the venous part, the appendage, and the vestibule; different aspects of each part allow us to distinguish morphologically between the left and right atrium. The human atrial conduction system consists of the sinus node and the atrioventricular node with no histologically specialized conduction pathways in the atrial chamber and an interatrial connection. The data show that the propagation of the impulse depends mainly on the myocardial architecture in the atria and the orientation of the myocytes plays a significant role in conduction. To complete the picture, it is also important to know how the atria develop and what is the embryonic origin of its different structures, as this may play a role in the development of some pathological conditions such as atrial fibrillation or certain types of congenital heart defects. Functional impairment of the atria can in some situations severely compromise heart pumping function, and conversely, can support it if other areas are damaged, balancing the blood flow to the body for some time. Key words Morphology of atrial chambers, Pectinate muscles, Atrial function.

Catheter Ablation in Atrial Fibrillation: Recent Advances

Atrial fibrillation (AF) is the leading cause of arrhythmia-related morbidity and mortality. Recurrent symptoms, hospitalizations, and cost burden to patients have necessitated treatments beyond antiarrhythmic drugs (AADs) for patients with AF. Catheter ablation has proven to be effective over medical therapy alone; however the recurrence rates for atrial tachyarrhythmias post-ablation remain significant, particularly in patients with persistent and long-standing persistent AF. Hence, new techniques for catheter ablation have arisen, such as non-thermal energy sources, novel catheters, electroanatomical mapping, and ablation of additional targets. In this review, we discuss the recent advances in the field of catheter ablation, including newer modalities for the prevention of adverse events and future perspectives.

Medical Devices in the Region of Tuscany, Italy: Definitions of Innovative Devices and Potentially Innovative Devices and Their Impact on Procurement Decisions

In the region of Tuscany in Italy, since 2019, medical devices belonging to risk classes 2b, 3, or active implantable have been managed by a multidisciplinary health-technology assessment body initially composed of eight members and extended to 23 members in 2022, thus creating the Centro Operativo. In 2021, an original algorithm for the identification of innovative devices based on objective criteria was developed and formally recognized over the following years. However, since these criteria identified only a small number of innovative devices, we tried to develop another algorithm aimed at identifying a new classification (called "potentially innovative device"), which was intended to be intermediate between full innovation and no innovation. Since preliminary analyses showed that objective criteria were not able to identify this intermediate classification, we relied on the expert opinion of the Centro Operativo for this purpose. In this article, we analyzed all the devices requested by Centro Operativo in the first half of 2024 for a total of 17 devices. Only one met the criteria of innovation and, therefore, was purchased; the other 11 were evaluated as adequate to be purchased based on clinical and/or economic reasons, whereas the remaining six did not. To create an operational relationship between these decisions and the definitions of innovativeness, the Centro Operativo explored a simple model wherein the 11 devices that failed to meet full innovativeness but were judged adequate to be purchased were classified as potentially innovative. In comparison, the remaining six devices were considered not innovative. On the one hand, we report the results of this preliminary experience; on the other hand, we plan to implement this form of management of high-technology devices into a regional regulation that will be applied for the next months in all hospitals of our region.

A cost-consequence analysis comparing three cardiac ablation strategies for the treatment of paroxysmal atrial fibrillation

BACKGROUND AND AIMS

Cardiac ablation is a well-established method for treating atrial fibrillation (AF). Pulsed field ablation (PFA) is a non-thermal therapeutic alternative to radiofrequency ablation (RFA) and cryoballoon ablation (CRYO). PFA uses high-voltage electric pulses to target cells. The present analysis aims to quantify the costs, outcomes, and resources associated with these three ablation strategies for paroxysmal AF.

METHODS

Real-world clinical data were prospectively collected during index hospitalization by three European medical centers (Belgium, Germany, the Netherlands) specialized in cardiac ablation. These data included procedure times (pre-procedural, skin-to-skin and post-procedural), resource use, and staff burden. Data regarding complications associated with each of the three treatment options and redo procedures were extracted from the literature. Costs were collected from hospital economic formularies and published cost databases. A cost-consequence model from the hospital perspective was built to estimate the impact of the three treatment options in terms of effectiveness and costs.

RESULTS

Across the three centers, N = 91 patients were included over a period of 12 months. A significant difference was seen in pre-procedural time (mean ± SD, PFA: 13.6 ± 3.7 min, CRYO: 18.8 ± 6.6 min, RFA: 20.4 ± 6.4 min; p < .001). Procedural time (skin-to-skin) was also different across alternatives (PFA: 50.9 ± 22.4 min, CRYO: 74.5 ± 24.5 min, RFA: 140.2 ± 82.4 min; p < .0001). The model reported an overall cost of €216,535 per 100 patients treated with PFA, €301,510 per 100 patients treated with CRYO and €346,594 per 100 patients treated with RFA. Overall, the cumulative savings associated with PFA (excluding kit costs) were €850 and €1,301 per patient compared to CRYO and RFA, respectively.

CONCLUSION

PFA demonstrated shorter procedure time compared to CRYO and RFA. Model estimates indicate that these time savings result in cost savings for hospitals and reduce outlay on redo procedures. Clinical practice in individual hospitals varies and may impact the ability to transfer the results of this analysis to other settings.