Randomized, Controlled Trial of the Safety and Effectiveness of a Contact Force-Sensing Irrigated Catheter for Ablation of Paroxysmal Atrial Fibrillation: Results of the TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) Study

Impact of irrigation flow rates on lesion size and safety of ablation catheters: an ex vivo porcine heart study

Radiofrequency (RF) catheter ablation is a well-established therapeutic approach for treating arrhythmias, where lesion size and safety are critical for efficacy. This study explored the impact of varying irrigation flow rates on lesion characteristics using the TactiFlex™ SE Ablation Catheter (TF) in an ex vivo porcine heart model, focusing on the size and safety outcomes associated with low versus standard flow rates. Myocardial slabs from porcine hearts were subjected to ablation using two types of irrigated catheters. Lesion formation was compared between low (8 mL/min for TF) and standard irrigation flow rates (13 mL/min for TF) across different power settings (30, 40, and 50 W). Outcome measures included lesion dimensions, incidence of steam pops, and impedance drops. A total of 210 lesions were generated under various settings. At low flow rates, the TF catheter safely formed larger lesions compared to the standard flow rates without a significant increase in steam pops or impedance drops. Lesions at low flow rates were comparable in size to those formed using other catheters under the standard settings. Conversely, the standard flow settings for TF produced smaller lesions but exhibited higher safety profiles, as evidenced by fewer steam pops and impedance drops. Lower irrigation flow rates using a TF catheter can achieve larger lesions without compromising safety, offering an optimization strategy for RF ablation procedures that balances efficacy and safety. These findings may guide clinicians in tailoring ablation strategies according to individual patient needs.

Representation of Women in Atrial Fibrillation Ablation Randomized Controlled Trials: Systematic Review

BACKGROUND

Sex inequality in randomized controlled trials (RCTs) related to cardiovascular disease has been observed. This study examined the proportion of women enrolled in atrial fibrillation (AF) ablation RCTs and the potential risks of underrepresentation of women.

METHODS AND RESULTS

We systematically searched PubMed and Embase for AF ablation RCTs published from 2015 to 2022. Participant characteristics were compared among trials with higher and lower proportions of women. Of 147 AF ablation RCTs (30,055 participants), only 10 trials had enrolled women ≥50% of the total participants. Additionally, 42 trials (28.57%) excluded pregnant/breastfeeding women; 6 (4.1%) excluded reproductive-age women without reliable birth control. The proportion of women in AF RCTs ranged from 9% to 71% (median 31.5%), whereas the median proportion of men was 67.7%. The rate of women included in the trials was stable from 2015 to 2022 (P=0.49). Study characteristics, including funding source, showed no correlation with the rate of inclusion of women. RCTs with a higher proportion of female participants enrolled older patients with AF, had a higher prevalence of hypertension but less persistent AF, and smaller left atrium size (P<0.05 for all). Biological sex was evaluated as a risk factor or in a subgroup analysis in 28 RCTs; 10.7% of these trials observed the implication of sex on their results.

CONCLUSION

Women were underrepresented in contemporary AF ablation RCTs. Additionally, women enrolled in AF RCTs were likely to have more comorbidities but less advanced AF, limiting the applicability of the results to women with AF.

Clinical experience of pulmonary vein isolation via single transseptal puncture in atrial fibrillation patients: Comprehensive characterization and follow-up

BACKGROUND

Atrial fibrillation is the most commonly observed cardiac rhythm disorder. Pulmonary vein isolation (PVI) is an effective treatment option to maintain sinus rhythm. This study evaluates the safety, efficacy, clinical outcomes and radiation exposures using a standardized single transseptal puncture (STP)-strategy.

METHODS

We analyzed data from patients who underwent our STP-ablation technique with transesophageal echocardiography (TEE) guidance at a university hospital and a regional tertiary health center in Switzerland between January 1, 2017, and May 30, 2022. Collected data included demographics, symptoms, echocardiography results, procedural details, complications and outcomes. Mean follow-up time was 21.4 ± 16 months.

RESULTS

The study population included 304 patients with a median age of 67 years, who had at least one ablation using our STP-approach. Among these, 248 (82 %) patients underwent de novo PVI with this technique. Ablation was successful in all patients with isolation of all pulmonary veins, with an average procedure duration of 120 min and an average fluoroscopy time of 3 min, resulting in a mean X-ray dose of 252 cGy × cm2. TEE guidance was performed in 235 (95 %) patients. During the first intervention, 17 complications occurred in 13 patients (5 %). After the first PVI, 135 (54 %) patients experienced no recurrence during the follow-up period. The one-year recurrence rate for atrial fibrillation requiring therapy was 30 %.

CONCLUSION

Our STP- approach demonstrated comparable success rates to traditional methods, with similar procedural durations, low radiation exposure and a low complication rate. Therefore, this method may offer procedural, economic and safety benefits without compromising efficacy or safety.

Hospital readmissions following catheter ablation for atrial fibrillation with THERMOCOOL™ STSF/ THERMOCOOL™ ST catheter with CARTO™ 3 system versus TactiCath™ catheter with EnSite™ system

Aim: Radiofrequency (RF) catheter ablation (CA) is a mainstay treatment for atrial fibrillation (AF). RF catheters with contact force (CF) sensing technology and electroanatomical mapping systems enable real-time assessment of catheter tip-tissue interface CF, facilitating individualized and precise CA. This study examined inpatient hospital readmissions in patients with AF treated with THERMOCOOL™ ST/ THERMOCOOL™ STSF catheter with the CARTO™ 3 System versus TactiCath™ catheter with the EnSite™ System. Materials & methods: Patients undergoing CA for AF between 1 July 2019 to 30 November 2021 were identified from the Premier Healthcare Database and grouped based on use of THERMOCOOL ST/STSF or TactiCath™. Study outcomes were all-cause, cardiovascular (CV)-, and AF-related inpatient readmission at 91-365-day post-CA. Inverse probability of treatment weighting of propensity scores balanced baseline patient, comorbidity and hospital characteristics. A weighted generalized estimating equation (GEE) model examined differences in readmission outcomes. Results: A total of 15,518 patients met inclusion criteria (THERMOCOOL ST/STSF, n = 13,001; TactiCath™, n = 2517). Patient characteristics were generally well-balanced after weighting. Patients treated with THERMOCOOL ST/STSF + CARTO 3 had a 20% lower likelihood of all-cause inpatient readmissions (7.8 vs 9.3%, chi-square p = 0.041; odds ratio [OR]: 0.80, 95% confidence interval [CI]: 0.66-0.96, GEE p = 0.019) and a 21% lower likelihood of CV-related inpatient readmission (5.2 vs 6.2%, chi-square p = 0.133, OR: 0.79, 95% CI: 0.62-0.99, GEE p = 0.043) in 91-365-days post-CA versus those treated with TactiCath™ + Ensite. No significant differences were observed for AF-related readmissions. Conclusion: Patients undergoing CA for AF treated with THERMOCOOL ST/STSF + CARTO 3 had a significantly lower risk of all-cause and CV-related inpatient hospital readmission versus those treated with TactiCath™ + Ensite.

Incidence, Mechanism, and Management of Atrial Ablation Procedure Complications: A Literature Review

The number of atrial catheter ablation procedures has significantly increased in recent years, becoming a first-line treatment modality for various supraventricular tachycardias due to their safety and efficacy. Complications, ranging from mild to life-threatening, can arise during different stages of the procedure, including vascular access complications (eg, hematoma or vascular fistula formation, retroperitoneal bleeding, etc.), thromboembolic complications (eg, stroke, transient ischemic attack, air embolism, etc.), mechanical complications (eg, cardiac perforation and tamponade), as well as pulmonary vein stenosis, atrio-esophageal fistulas, phrenic nerve injury, and gastroparesis. Atrial fibrillation ablation procedures, in particular, carry a higher complication rate due to their complexity. This review discusses the incidence, mechanisms, diagnosis, management, and prevention of these complications. Key strategies to reduce risks include optimized anticoagulation protocols, the use of intracardiac echocardiography, reduced energy delivery, and esophageal temperature monitoring, among others. Timely detection and intervention, especially in the case of life-threatening complications, is crucial. Pulsed-field ablation, a novel technique using nonthermal electrical energy, offers a promising and precise alternative to conventional thermal ablation with a favorable safety profile. However, further research is needed to fully understand its complications and refine management strategies.

Catheter ablation using pulsed-field energy: Do we finally have the magic wand to defeat atrial fibrillation?

Clinical outcomes of catheter ablation remain suboptimal in patients with atrial fibrillation (AF), particularly in those with persistent AF, despite decades of research, clinical trials, and technological advancements. Recently, pulsed-field ablation (PFA), a promising non-thermal technology, has been introduced to improve procedural outcomes. Its unique feature of myocardial selectivity offers safety advantages by avoiding potential harm to vulnerable adjacent structures during AF ablation. However, despite the global enthusiasm within the electrophysiology community, recent data indicate that PFA is still far from being a "magic wand" for addressing such a complex and challenging arrhythmia as AF. More progress is needed in mapping processes rather than in ablation technology. This editorial reviews relevant available data and explores future research directions for PFA.

Linear Ablation Using a Contact Force-Sensing Catheter in Ablation for Persistent Atrial Fibrillation: A Prospective Randomized Trial

Background/Objectives: Pulmonary vein isolation (PVI) using radiofrequency catheter ablation with contact force (CF)-sensing technology has improved long-term outcomes in patients with atrial fibrillation. This prospective randomized study aimed to assess the efficacy and safety of CF-sensing technology for additional left atrial (LA) linear ablation of persistent AF (PerAF). Methods: After PVI, anteromitral (AM) line and roof line ablation were performed using a CF-sensing catheter. Patients were randomly assigned to either the CF-sensing (CFS) group or the CF-blind control (Blind) group. The primary endpoint was atrial arrhythmia recurrence. LA late gadolinium enhancement (LA-LGE) MRI was conducted at baseline and 1-year follow-up for long-term lesion evaluation. Results: A total of 62 patients with drug-refractory PerAF were enrolled (mean age: 58 ± 10 years; 77% male). The success rates of AM and roof line block were 97% and 100% in the CFS group (n = 33) and 93% and 90% in the Blind group (n = 29). The time to achieve block was reduced in the CFS group (AM: 36 ± 22 vs. 48 ± 28 min, p = 0.068; roof: 19 ± 14 vs. 27 ± 15 min, p = 0.031). The maximum CF for safety endpoints was significantly lower in the CFS group (AM: 42 vs. 69 g, p < 0.001; roof: 33 vs. 49 g, p = 0.003). Full linear LA-LGE formation on 1-year MRI did not differ significantly between the groups (AM: 17 vs. 36%; roof; 29 vs. 24%, both p = NS). Kaplan-Meier estimates of AF/AT-free survival after ablation procedures were 63.6% in the CFS group and 58.6% in the Blind group (log-rank p = 0.837). Conclusions: In patients with PerAF, additional LA linear ablation following PVI using CF-sensing technology improved procedural safety and reduced the time needed to achieve conduction block. However, it did not significantly influence clinical outcomes or the formation of permanent full linear lesions.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

Optimizing ablation sites for pulmonary vein isolation reconnections: A novel approach using an emphasis map combined with the peak frequency and local activation timing map

BACKGROUND

Although catheter ablation techniques for atrial fibrillation (AF) have advanced, some cases of reconnections after pulmonary vein (PV) isolation still exist. The diversity of the anatomic wall thickness and fiber orientation around the PVs might contribute to reconnections.

OBJECTIVE

The purpose of this study was to investigate the utility of the emphasis map's emphasize settings to determine optimal ablation sites.

METHODS

Patients undergoing AF ablation with the EnSite X system who had PV reconnections were included. The emphasis map (a combination of peak frequency and local activation timing [LAT] maps) was created to obtain the emphasize settings for indicating the optimal ablation site (Emphasis group). In another group, the ablation site was determined based on LAT mapping (LAT group).

RESULTS

A total of 64 patients (age 69 ± 9 years; 50 males), and 109 PVs were found to be reconnected and analyzed. Gaps were observed at 55 and 68 points of the PV isolation in the Emphasis and LAT groups, respectively. The number of ablation points needed to successfully eliminate the gaps, and the total energy were markedly smaller (1.6 ± 1.1 vs. 6.3 ± 3.7, P <.001; 3541 ± 2060 J vs 5606 ± 3728 J, P = .001) in the Emphasis group than in the LAT group, respectively. The average optimal emphasize setting was 338 ± 67 Hz in the Emphasis group.

CONCLUSION

Adjusting the emphasize settings visualized the optimal ablation site, and the number of ablation points needed to reisolate the PV might be markedly reduced.

Catheter ablation for atrial fibrillation: indications and future perspective

Recent advances in techniques, technologies and proven superiority over anti-arrhythmic drugs have made catheter ablation the cornerstone of management for atrial fibrillation (AF), which has shown a steady increase in prevalence in the ageing population worldwide. The aim of therapeutic interventions is to achieve stable sinus rhythm that would improve the quality of life and reduce the risk of AF-associated complications. Pulmonary veins (PVs) were first described as the source of initiation of ectopic triggers driving AF, which led to the establishment of PV isolation (PVI) as the most widely practiced procedure to treat AF. Antral PVI is still recognized as the stand-alone ablation strategy for newly diagnosed paroxysmal AF (PAF). However, in non-PAF patients, PVI seems to be inadequate and several adjunctive strategies, including ablation of left atrial posterior wall and non-PV triggers, AF mapping and ablation of rotors and drivers, ethanol infusion of vein of Marshall and renal denervation, etc. have been reported with mixed results. Recent trials have also documented the benefits of early rhythm control in preventing cardiovascular events in addition to slowing the progression of PAF to more persistent forms. Similarly, very late relapse of the arrhythmia after successful PVI has drawn attention to the critical role of non-PV triggers and highlighted their relevance as potential ablation targets during repeat procedures. Ablation technology is also under constant evolution with the introduction of non-thermal energy sources and new tools to create durable lesions. This review summarizes the indications, advancements, and future perspective of AF ablation.

Real-world data of radiofrequency catheter ablation in paroxysmal atrial fibrillation: Short- and long-term clinical outcomes from the prospective multicenter REAL-AF Registry

BACKGROUND

The safety and long-term efficacy of radiofrequency (RF) catheter ablation (CA) of paroxysmal atrial fibrillation (PAF) has been well established. Contemporary techniques to optimize ablation delivery, reduce fluoroscopy use, and improve clinical outcomes have been developed.

OBJECTIVE

The purpose of this study was to assess the contemporary real-world practice approach and short and long-term outcomes of RF CA for PAF through a prospective multicenter registry.

METHODS

Using the REAL-AF (Real-world Experience of Catheter Ablation for the Treatment of Symptomatic Paroxysmal and Persistent Atrial Fibrillation; ClincalTrials.gov Identifier: NCT04088071) Registry, patients undergoing RF CA to treat PAF across 42 high-volume institutions and 79 experienced operators were evaluated. The procedures were performed using zero or reduced fluoroscopy, contact force sensing catheters, wide area circumferential ablation, and ablation index as a guide with a target of 380-420 for posterior and 500-550 for anterior lesions. The primary efficacy outcome was freedom from all-atrial arrhythmia recurrence at 12 months.

RESULTS

A total of 2470 patients undergoing CA from January 2018 to December 2022 were included. Mean age was 65.2 ±11.14 years, and 44% were female. Most procedures were performed without fluoroscopy (71.5%), with average procedural and total RF times of 95.4 ± 41.7 minutes and 22.1±11.8 minutes, respectively. At 1-year follow-up, freedom from all-atrial arrhythmias was 81.6% with 89.7% of these patients off antiarrhythmic drugs. No significant difference was identified comparing pulmonary vein isolation vs pulmonary vein isolation plus ablation approaches. The complication rate was 1.9%.

CONCLUSION

Refinement of RF CA to treat PAF using contemporary tools, standardized protocols, and electrophysiology laboratory workflows resulted in excellent short- and long-term clinical outcomes.

Anesthetic Techniques for Ablation in Atrial Fibrillation: A Comparative Review

Atrial fibrillation, the most prevalent cardiac arrhythmia, has witnessed significant advancements in treatment modalities, transitioning from invasive procedures like the maze procedure to minimally invasive catheter ablation techniques. This review focuses on recent improvements in anesthetic approaches that enhance outcomes in catheter atrial fibrillation ablation. We highlight the efficacy of contact force sensing catheters with steerable introducer sheaths, which outperform traditional catheters by ensuring more effective contact time and lesion formation. Comparing general anesthesia with conscious sedation, we find that general anesthesia provides superior catheter stability due to reduced respiratory variability, resulting in more effective lesion formation, and reduced pulmonary vein reconnection. The use of high-frequency jet ventilation under general anesthesia, delivering low tidal volumes, effectively minimizes left atrial movement, decreasing catheter displacement and procedure time, and reducing recurrence in paroxysmal atrial fibrillation. An alternative, high-frequency low tidal volume ventilation using conventional ventilators, also shows improved catheter stability and lesion durability compared to traditional ventilation methods. However, a detailed comparative study of high-frequency jet ventilation, high-frequency low tidal volume ventilation, and conventional mechanical ventilation in catheter ablation for atrial fibrillation is lacking. This review emphasizes the need for such studies to identify optimal anesthetic techniques, potentially enhancing patient outcomes in atrial fibrillation treatment. Our findings suggest that careful selection of anesthetic methods, including ventilation strategies, plays a crucial role in the success of catheter ablation for atrial fibrillation, warranting further research for evidence-based practice.

Lesion size index-guided radiofrequency catheter ablation using an impedance-based three-dimensional mapping system to treat sustained atrial tachycardia in a horse

Sustained atrial tachycardia at an atrial rate of 191/min on the surface ECG was detected in a 6-year-old Warmblood mare. The vectorcardiogram obtained from a 12-lead ECG suggested a caudo-dorsal right atrial origin of the arrhythmia. Impedance-based three-dimensional electro-anatomical mapping, using the EnSite™ Precision Cardiac Mapping System revealed a clockwise macro-reentry around a line of conduction block in the caudomedial right atrium. Ten radiofrequency applications were applied to isolate the caudal vena cava myocardial sleeves at a power of 35 W and mean contact force of 14 ± 3 g until a lesion size index of 6 was reached. Sinus rhythm was restored at the first energy application. Successful isolation was confirmed by demonstrating entrance and exit block. Holter monitoring 5 days post-ablation revealed no abnormalities. To date, 9 months after treatment, no recurrence has been observed. The use of lesion size index-guided ablation and isolation of the arrhythmogenic substrate in the caudal vena cava may minimise the risk of recurrence.

Early rapid local impedance drop is associated with acute lesion efficacy during pulmonary vein isolation

AIMS

The predictive role of local impedance (LI) drop in lesion formation using a novel contact force sensing ablation catheter was recently described. The purpose of our current study was to assess the temporal characteristics of LI drop during ablation and its correlation with acute lesion efficacy.

METHODS AND RESULTS

Point-by-point pulmonary vein isolation was performed. The efficacy of applications was determined by pacing along the circular ablation line and assessing loss of capture. Local impedance, contact force, and catheter position data with high resolution were analysed and compared in successful and unsuccessful applications. Five hundred and fifty-nine successful and 84 unsuccessful applications were analysed. The successful applications showed higher baseline LI (P < 0.001) and larger LI drop during ablation (P < 0.001, for all). In case of unsuccessful applications, after a moderate but significant drop from baseline to the 2 s time point (153 vs. 145 Ω, P < 0.001), LI did not change further (P = 0.99). Contradictorily, in case of successful applications, the LI significantly decreased further (baseline-2 s-10 s: 161-150-141 Ω, P < 0.001 for all). The optimal cut-point for the LI drop indicating unsuccessful application was <9 Ω at the 4-s time point [AUC = 0.73 (0.67-0.76), P < 0.001]. Failing to reach this cut-point predicted unsuccessful applications [OR 3.82 (2.34-6.25); P < 0.001].

CONCLUSION

A rapid and enduring drop of the LI may predict effective lesion formation, while slightly changing or unchanged LI is associated with unsuccessful applications. A moderate LI drop during the first 4 s of radiofrequency application predicts ineffective radiofrequency delivery.

Cardiac-gated spectroscopic photoacoustic imaging for ablation-induced necrotic lesion visualization

Radiofrequency (RF) ablation is a minimally invasive therapy for atrial fibrillation. Conventional RF procedures lack intraoperative monitoring of ablation-induced necrosis, complicating assessment of completeness. While spectroscopic photoacoustic (sPA) imaging shows promise in distinguishing ablated tissue, multi-spectral imaging is challenging in vivo due to low imaging quality caused by motion. Here, we introduce a cardiac-gated sPA imaging (CG-sPA) framework to enhance image quality using a motion-gated averaging filter, relying on image similarity. Necrotic extent was calculated based on the ratio between spectral unmixed ablated tissue contrast and total tissue contrast, visualizing as a continuous color map to highlight necrotic area. The validation of the concept was conducted in both ex vivo and in vivo swine models. The ablation-induced necrotic lesion was successfully detected throughout the cardiac cycle through CG-sPA imaging. The results suggest the CG-sPA imaging framework has great potential to be incorporated into clinical workflow to guide ablation procedures intraoperatively.

Laryngeal mask airway versus endotracheal intubation as general anesthesia airway managements for atrial fibrillation catheter ablation: a comparative analysis based on propensity score matching

BACKGROUND

The current evidence on the use of laryngeal mask airway (LMA) as an airway management technique for general anesthesia (GA) during atrial fibrillation (AF) catheter ablation (CA) is insufficient. This study aims to compare the feasibility, safety, and clinical benefits of LMA and endotracheal intubation (ETI) for airway management in AF CA.

METHODS

One hundred fifty-two consecutive patients with AF who underwent CA under GA were included and divided into two groups based on different airway management methods (66 in the LMA group, 86 in the ETI group). After propensity score matching, a final analysis cohort of 132 patients was obtained to compare procedural parameters, adverse events, and prognosis between the two groups.

RESULTS

The LMA group exhibited significantly shorter total procedural time (p = 0.039), anesthesia induction time (p = 0.015), and recovery time (p = 0.006) compared to the ETI group. The mean arterial pressure (MAP) and heart rate were significantly lower in the LMA group during extubation and 1-min post-extubation (p < 0.05). Furthermore, the LMA group demonstrated lower MAP levels during intubation (p = 0.029). The incidences of intraoperative hypotension (p = 0.017) and bradycardia (p = 0.032) were significantly lower in the LMA group. The incidences of delayed recovery or delirium (p = 0.027), laryngeal or airway injury (p = 0.016), cough or bucking (p = 0.001), and sore throat (p < 0.001) were significantly lower in the LMA group. There were no statistically significant differences in catheter stability parameters and sinus rhythm maintenance rates between the two groups (p > 0.05).

CONCLUSION

LMA is feasible, safe, and effective in AF CA as an optimized airway management technique for GA.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

Trends in safety of catheter-based electrophysiology procedures in the last 2 decades: A meta-analysis

BACKGROUND

Rapid technologic development and expansion of procedural expertise have led to widespread proliferation of catheter-based electrophysiology procedures. It is unclear whether these advances come at cost to patient safety.

OBJECTIVE

This meta-analysis aimed to assess complication rates after modern electrophysiology procedures during the lifetime of the procedures.

METHODS

A comprehensive search was performed to identify relevant data published before May 30, 2023. Studies were included if they met the following inclusion criteria: prospective trials or registries, including comprehensive complications data; and patients undergoing atrial fibrillation ablation, ventricular tachyarrhythmia ablation, leadless cardiac pacemaker implantation, and percutaneous left atrial appendage occlusion. Pooled incidences of procedure-related complications were individually assessed by random effects models to account for heterogeneity. Temporal trends in complications were investigated by clustering trials by publication year (2000-2018 vs 2019-2023).

RESULTS

A total of 174 studies (43,914 patients) met criteria for analysis: 126 studies of atrial fibrillation ablation (n = 24,057), 25 studies of ventricular tachyarrhythmia ablation (n = 1781), 21 studies of leadless cardiac pacemaker (n = 8896), and 18 studies of left atrial appendage occlusion (n = 9180). The pooled incidences of serious procedure-related complications (3.49% [2000-2018] vs 3.05% [2019-2023]; P < .001), procedure-related stroke (0.46% vs 0.28%; P = .002), pericardial effusion requiring intervention (1.02% vs 0.83%; P = .037), and procedure-related death (0.15% vs 0.06%; P = .003) significantly decreased over time. However, there was no significant difference in the incidence of vascular complications over time (1.86% vs 1.88%; P = .888).

CONCLUSION

Despite an increase in cardiac electrophysiology procedures, procedural safety has improved over time.

The importance of electrode-tissue proximity in creating pulsed field ablation lesions: insights from a sub-acute preclinical model

BACKGROUND

We sought to evaluate the anatomic and functional lesion development over time at different atrial sites immediately following delivery of pulsed field ablation (PFA).

METHODS

Using a porcine model, PFA ablations were performed in the superior vena cava (SVC), right atrial lateral wall (RA), left atrial appendage (LAA), and right superior pulmonary vein (RSPV) using four different PFA profiles. Mapping was done sequentially in 5-20-min increments up to 280-min post lesion delivery for low voltage area (LVA) assessment and conduction velocity. Lesion characteristics were noted with voltage mapping immediately post ablation and at the serial time points.

RESULTS

In 9 animals, 33 sites were ablated. None of the four different profiles across all sites showed any statistical difference on acute lesion formation or persistence. Higher tissue contact was observed in the SVC and RSPV and lower tissue contact was observed in the LAA and RA locations. Higher contact areas were noted to have higher density electroanatomic low voltage area (LVA) (12/14 vs 5/18, p = 0.01) and larger lesions on gross pathology (2 /14 vs 6/16, p = 0.01) compared to lower contact areas. Lesion regression occurred in 16/33 sites. Sustained lesions were significantly more prevalent in higher versus lower contact sites (65% vs 38%, p = 0.037).

CONCLUSION

The development of significant and durable lesions for PFA in a porcine model appears to be dependent on tissue proximity and contact.

Deep learning-based multimodal fusion of the surface ECG and clinical features in prediction of atrial fibrillation recurrence following catheter ablation

BACKGROUND

Despite improvement in treatment strategies for atrial fibrillation (AF), a significant proportion of patients still experience recurrence after ablation. This study aims to propose a novel algorithm based on Transformer using surface electrocardiogram (ECG) signals and clinical features can predict AF recurrence.

METHODS

Between October 2018 to December 2021, patients who underwent index radiofrequency ablation for AF with at least one standard 10-second surface ECG during sinus rhythm were enrolled. An end-to-end deep learning framework based on Transformer and a fusion module was used to predict AF recurrence using ECG and clinical features. Model performance was evaluated using areas under the receiver operating characteristic curve (AUROC), sensitivity, specificity, accuracy and F1-score.

RESULTS

A total of 920 patients (median age 61 [IQR 14] years, 66.3% male) were included. After a median follow-up of 24 months, 253 patients (27.5%) experienced AF recurrence. A single deep learning enabled ECG signals identified AF recurrence with an AUROC of 0.769, sensitivity of 75.5%, specificity of 61.1%, F1 score of 55.6% and overall accuracy of 65.2%. Combining ECG signals and clinical features increased the AUROC to 0.899, sensitivity to 81.1%, specificity to 81.7%, F1 score to 71.7%, and overall accuracy to 81.5%.

CONCLUSIONS

The Transformer algorithm demonstrated excellent performance in predicting AF recurrence. Integrating ECG and clinical features enhanced the models' performance and may help identify patients at low risk for AF recurrence after index ablation.

Comparative Analysis of Clinical Outcomes of High-power, Short-duration Ablation versus Low-power, Long-duration Ablation Strategy in Patients with Atrial Fibrillation: A Comprehensive Umbrella Review of Meta-analyses

Atrial fibrillation (AF) affects around 33 million people worldwide, rendering it a common cardiac arrhythmia. Catheter ablation (CA) has evolved as a leading therapeutic intervention for symptomatic AF. This umbrella review systematically evaluates existing systematic reviews and meta-analyses to assess the safety, efficacy, and potential of high-power, short-duration (HPSD) ablation as an alternative therapy option for AF. A thorough exploration was undertaken across PubMed, the Cochrane Library, and Embase to identify pertinent studies for inclusion in this umbrella review. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method was employed to assess the overall certainty of the evidence comprehensively, and the quality of the incorporated reviews was meticulously evaluated through use of the AMSTAR 2 tool, the Cochrane Collaboration tool, and the Newcastle-Ottawa scale. In this study, we initially identified 35 systematic reviews and meta-analyses, narrowing them down to a final selection of 11 studies, which collectively integrated data from 6 randomized controlled trials and 26 observational studies. For primary efficacy outcomes, the HPSD approach led to a non-significant decrease in the risk of atrial tachyarrhythmia recurrence (risk ratio [RR], 0.88; 95% confidence interval [CI], 0.70-1.12; I 2 = 90%; P = .31) and a significantly reduced risk of AF recurrence (RR, 0.53; 95% CI, 0.42-0.67; I 2 = 0%; P < .00001) compared to the low-power, long-duration (LPLD) approach. In terms of primary safety outcomes, the HPSD approach significantly reduced the risk of esophageal thermal injury (ETI) (RR, 0.71; 95% CI, 0.61-0.83; I 2 = 0%; P < .00001) and facilitated a non-significant decrease in the risk of other major complications (RR, 0.87; 95% CI, 0.73-1.03; I 2 = 0%; P = .10). In conclusion, HPSD therapy is safer and more effective than LPLD therapy, facilitating decreased AF recurrence rates along with reductions in ETI, total procedure duration, ablation number, ablation time, fluoroscopy time, and acute pulmonary vein reconnection.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Esophageal injury, perforation, and fistula formation following atrial fibrillation ablation

BACKGROUND

Esophageal perforation and fistula formation are rare but serious complications following atrial fibrillation ablation. In this review article, we outline the incidence, pathophysiology, predictors, and preventative strategies of this dreaded complication.

METHODS

We conducted an electronic search in 10 databases/electronic search engines to access relevant publications. All articles reporting complications following atrial fibrillation ablation, including esophageal injury and fistula formation, were included for systematic review.

RESULTS

A total of 130 manuscripts were identified for the final review process. The overall incidence of esophageal injury following atrial fibrillation ablation was significantly higher with thermal ablation modalities (radiofrequency 5-40%, cryoballoon 3-25%, high-intensity focused ultrasound < 10%) as opposed to non-thermal ablation modalities (no cases reported to date). The incidence of esophageal perforation and fistula formation with the use of thermal ablation modalities is estimated to occur in less than 0.25% of all atrial fibrillation ablation procedures. The use of luminal esophageal temperature monitoring probe and mechanical esophageal deviation showed protective effect toward reducing the incidence of this complication. The prognosis is very poor for patients who develop atrioesophageal fistula, and the condition is rapidly fatal without surgical intervention.

CONCLUSIONS

Esophageal perforation and fistula formation following atrial fibrillation ablation are rare complications with poor prognosis. Various strategies have been proposed to protect the esophagus and reduce the incidence of this fearful complication. Pulsed field ablation is a promising new ablation technology that may be the future answer toward reducing the incidence of esophageal complications.

Characterizing lesion morphology of a novel diamond-tip temperature-controlled irrigated radiofrequency ablation catheter

BACKGROUND

The DiamondTemp ablation (DTA) system is a novel temperature-controlled irrigated radiofrequency (RF) ablation system that accurately measures tip-tissue temperatures for real-time power modulation. Lesion morphologies from longer RF durations with the DTA system have not been previously described. We sought to evaluate lesion characteristics of the DTA system when varying the application durations.

METHODS

A bench model using porcine myocardium was used to deliver discrete lesions in a simulated clinical environment. The DTA system was power-limited at 50 W with temperature set-points of 50 °C and 60 °C (denoted Group_50 and Group_60). Application durations were randomized with a range of 5-120 s.

RESULTS

In total, 280 applications were performed. Steam pops were observed in five applications: two applications at 90 s and three applications at 120 s. Lesion size (depth and maximum width) increased significantly with longer applications, until 60 s for both Group_50 and Group_60 (depth: 4.5 ± 1.2 mm and 5.6 ± 1.3 mm; maximum width: 9.3 ± 2.7mm and 11.2 ± 1.7mm, respectively). As lesions transition from resistive to conductive heating (longer than 10 s), the maximum width progressed in a sub-surface propagation. Using a "Time after Temperature 60 °C" (TaT60) analysis, depths of 2-3 mm occur in 0-5 s and depths plateau at 4.6 ± 0.8 mm between 20 and 30 s.

CONCLUSIONS

The DTA system rapidly creates wide lesions with lesion depth increasing over time with application durations up to 60 s. Using a TaT60 approach is a promising ablation guidance that would benefit from further investigation.

Optimizing the management of electrophysiology labs in Chinese hospitals using a discrete event simulation tool

BACKGROUND

The growing demand for electrophysiology (EP) treatment in China presents a challenge for current EP care delivery systems. This study constructed a discrete event simulation (DES) model of an inpatient EP care delivery process, simulating a generalized inpatient journey of EP patients from admission to discharge in the cardiology department of a tertiary hospital in China. The model shows how many more patients the system can serve under different resource constraints by optimizing various phases of the care delivery process.

METHODS

Model inputs were based on and validated using real-world data, simulating the scheduling of limited resources among competing demands from different patient types. The patient stay consists of three stages, namely: the pre-operative stay, the EP procedure, and the post-operative stay. The model outcome was the total number of discharges during the simulation period. The scenario analysis presented in this paper covers two capacity-limiting scenarios (CLS): (1) fully occupied ward beds and (2) fully occupied electrophysiology laboratories (EP labs). Within each CLS, we investigated potential throughput when the length of stay or operative time was reduced by 10%, 20%, and 30%. The reductions were applied to patients with atrial fibrillation, the most common indication accounting for almost 30% of patients.

RESULTS

Model validation showed simulation results approximated actual data (137.2 discharges calculated vs. 137 observed). With fully occupied wards, reducing pre- and/or post-operative stay time resulted in a 1-7% increased throughput. With fully occupied EP labs, reduced operative time increased throughput by 3-12%.

CONCLUSIONS

Model validation and scenario analyses demonstrated that the DES model reliably reflects the EP care delivery process. Simulations identified which phases of the process should be optimized under different resource constraints, and the expected increases in patients served.

Local impedance and contact force guidance to predict successful cavotricuspid isthmus ablation with a zero-fluoroscopy approach

Introduction

A new technology capable of monitoring local impedance (LI) and contact force (CF) has recently been developed. At the same time, there is growing concern regarding catheter ablation performed under fluoroscopy guidance, due to its harmful effects for both patients and practitioners. The aim of this study was to assess the safety and effectiveness of zero-fluoroscopy cavotricuspid isthmus (CTI) ablation monitoring LI drop and CF as well as to elucidate if these parameters can predict successful radiofrequency (RF) applications in CTI ablation.

Methods

We conducted a prospective observational study recruiting 50 consecutive patients who underwent CTI ablation. A zero-fluoroscopy approach guided by the combination of LI drop and CF was performed. In each RF application, CF and LI drop were monitored. A 6-month follow-up visit was scheduled to assess recurrences.

Results

A total of 767 first-pass RF applications were evaluated in 50 patients. First-pass effective RF applications were associated with greater LI drops: absolute LI drops (30.05 ± 6.23 Ω vs. 25.01 ± 5.95 Ω), p = 0.004) and relative LI drops (-23.3 ± 4.9% vs. -18.3 ± 5.6%, p = 0.0005). RF applications with a CF between 5 and 15 grams achieved a higher LI drop compared to those with a CF below 5 grams (29.4 ± 8.76 Ω vs. 24.8 ± 8.18 Ω, p < 0.0003). However, there were no significant differences in LI drop between RF applications with a CF between 5 and 15 grams and those with a CF beyond 15 grams (29.4 ± 8.76 Ω vs. 31.2 ± 9.81 Ω, p = 0.19). CF by itself, without considering LI drop, did not predict effective RF applications (12.3 ± 7.54 g vs. 11.18 ± 5.18 g, p = 0.545). Successful CTI ablation guided by a zero-fluoroscopy approach was achieved in all patients. Only one patient experienced a recurrence during the 6-month follow-up.

Conclusions

LI drop (absolute and relative values) appears to be a good predictor of successful RF applications to achieve CTI conduction block. The optimal CF to achieve a good LI drop is between 5 and 15 g. A zero-fluoroscopy approach guided by LI and CF was feasible, effective, and safe.

[Catheter ablation of atrial fibrillation : Evidence and current techniques]

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia with increasing clinical and healthcare economic relevance. A timely treatment prevents or slows the remodelling process of the atrial and ventricular myocardium initiated by AF, emphasizing its relevance especially in heart failure patients. Catheter ablation for the treatment of AF is safe and effective. The three ablation techniques currently used are comparable in terms of success rates but differ in terms of risk profile and the type of lesion formation.

Atrial Fibrillation Ablation: Current Practice and Future Perspectives

Catheter ablation to perform pulmonary vein isolation (PVI) is established as a mainstay in rhythm control of atrial fibrillation (AF). The aim of this review is to provide an overview of current practice and future perspectives in AF ablation. The main clinical benefit of AF ablation is the reduction of arrhythmia-related symptoms and improvement of quality of life. Catheter ablation of AF is recommended, in general, as a second-line therapy for patients with symptomatic paroxysmal or persistent AF, who have failed or are intolerant to pharmacological therapy. In selected patients with heart failure and reduced left-ventricular fraction, catheter ablation was proven to reduce all-cause mortality. Also, optimal management of comorbidities can reduce AF recurrence after AF ablation; therefore, multimodal risk assessment and therapy are mandatory. To date, the primary ablation tool in widespread use is still single-tip catheter radiofrequency (RF) based ablation. Additionally, balloon-based pulmonary vein isolation (PVI) has gained prominence, especially due to its user-friendly nature and established safety and efficacy profile. So far, the cryoballoon (CB) is the most studied single-shot device. CB-based PVI is characterized by high efficiency, convincing success rates, and a beneficial safety profile. Recently, CB-PVI as a first-line therapy for AF was shown to be superior to pharmacological treatment in terms of efficacy and was shown to reduce progression from paroxysmal to persistent AF. In this context, CB-based PVI gains more and more importance as a first-line treatment choice. Non-thermal energy sources, namely pulsed-field ablation (PFA), have garnered attention due to their cardioselectivity. Although initially applied via a basket-like ablation tool, recent developments allow for point-by-point ablation, particularly with the advent of a novel lattice tip catheter.

Safety and effectiveness of the first contact force ablation catheter with a flexible tip

Background

Catheter ablation is an established therapy for paroxysmal atrial fibrillation (PAF). The TactiFlex Ablation Catheter, Sensor Enabled (TactiFlex SE) is a next-generation radiofrequency ablation catheter incorporating fiber optics-based contact force-sensing technology with a flexible, laser-cut tip.

Objective

The study sought to evaluate the safety and effectiveness of the TactiFlex SE ablation catheter for treatment of drug-refractory PAF.

Methods

The TactiFlex AF investigational device exemption was a prospective, nonrandomized, multicenter clinical study. Enrollment began on June 26, 2020 and completed June 18, 2021. Subjects with PAF underwent de novo pulmonary vein isolation and, if indicated, ablation for typical atrial flutter. Subjects were followed for 12 months.

Results

Of the 355 subjects enrolled at 37 sites worldwide, 334 underwent ablation with the TactiFlex SE catheter. The Kaplan-Meier estimate of 12-month freedom from AF/atrial flutter (AFL)/atrial tachycardia recurrence was 72.9% (95% confidence interval [CI] 95% CI 67.2%-77.8%) and clinical success was 83.6% (95% CI 95% CI 78.1%-87.2%). As-treated analyses compared subjects treated at high power (left atrium time-averaged power setting 40-50 W; n = 222) vs low power (<40 W; n = 97). The Kaplan-Meier estimate of 12-month freedom from AF/AFL/atrial tachycardia recurrence was 76.4% (95% CI 69.3%-82.0%) and clinical success was 83.9% (95% CI 77.5%-88.6%) in the high-power group compared with 66.8% (95% CI 56.1%-75.5%) and 80.7% (95% CI 70.8%- 87.5%), respectively, in the low-power group. The primary safety event rate in all treated subjects was 4.3%; 4.1% in the HP group and 5.2% in the LP group (P = .7671).

Conclusion

TactiFlex SE is safe and effective for treatment of drug-refractory PAF and concomitant AFL and enables more efficient procedures than previous generation catheters.

Robotic magnetic navigation-guided catheter ablation establishes highly effective pulmonary vein isolation in patients with paroxysmal atrial fibrillation when compared to conventional ablation techniques

INTRODUCTION

Pulmonary vein isolation (PVI) is a pivotal part of ablative therapy for atrial fibrillation (AF). Currently, there are multiple techniques available to realize PVI, including: manual-guided cryoballoon (MAN-CB), manual-guided radiofrequency (MAN-RF), and robotic magnetic navigation-guided radiofrequency ablation (RMN-RF). There is a lack of large prospective trials comparing contemporary RMN-RF with the more conventional ablation techniques. This study prospectively compared three catheter ablation techniques as treatment of paroxysmal AF.

METHODS

This multicenter, prospective study included patients with paroxysmal AF who underwent their first ablation procedure. Procedural parameters (including procedural efficiency), complication rates, and freedom of AF during 12-month follow-up, were compared between three study groups which were defined by the utilized ablation technique.

RESULTS

A total of 221 patients were included in this study. Total procedure time was significantly shorter in MAN-CB (78 ± 21 min) compared to MAN-RF (115 ± 41 min; p < .001) and compared to RMN-RF (129 ± 32 min; p < .001), whereas it was comparable between the two radiofrequency (RF) groups (p = .062). A 3% complication rate was observed, which was comparable between all groups. At 12-month follow-up, AF recurrence was observed in 40 patients (19%) and was significantly lower in the robotic group (MAN-CB 19 [24%], MAN-RF 16 [23%], RMN-RF 5 [8%] AF recurrences, p = .045) (multivariate hazard ratio of RMN-RF on AF recurrence 0.32, 95% confidence interval: 0.12-0.87, p = .026).

CONCLUSION

RMN-guided PVI results in high freedom of AF in patients with paroxysmal AF, when compared to cryoablation and manual RF ablation. Cryoablation remains the most time-efficient ablation technique, whereas RMN nowadays has comparable efficiency with manual RF ablation.

Posterior Wall Isolation Improves Outcomes for Persistent AF With Rapid Posterior Wall Activity: CAPLA Substudy

BACKGROUND

Pulmonary vein isolation (PVI) is less effective in persistent atrial fibrillation (PerAF) than in paroxysmal atrial fibrillation (AF). However, the CAPLA (Effect of Catheter Ablation Using Pulmonary Vein Isolation With vs Without Posterior Left Atrial Wall Isolation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation: The CAPLA randomized clinical trial) of PVI vs posterior wall isolation (PWI) did not support empiric PWI in PerAF. We examined pulmonary vein (PV) and posterior wall (PW) electrical characteristics to determine if select patients may benefit from additional PWI.

OBJECTIVES

This study sought to determine the impact of PV and PW electrical characteristics on AF ablation outcomes in the CAPLA randomized study.

METHODS

Participants in spontaneous AF at the time of ablation were included from the CAPLA study. The mean, shortest, and longest PV, PW, and left atrial (LA) appendage cycle length measurements were annotated preablation using a multipolar catheter for 100 consecutive cycles. Next, cardioversion was performed with a high-density LA voltage map completed. Cox proportional hazards regression was utilized to determine clinical and electroanatomic predictors of AF recurrence overall and according to ablation strategy. Follow-up included twice daily single-lead electrocardiograms or continuous monitoring for 12 months.

RESULTS

A total of 151 patients (27% female, age 65 ± 9 years, 18% long-standing PerAF, LA volume index 52 ± 16 mL/m2, median AF duration 5 months [IQR: 2-10 months]) were in AF on the day of procedure and were randomized to PVI alone (50%) or PVI+PWI (50%) according to the CAPLA randomized clinical trial protocol. Baseline clinical, echocardiographic, and electroanatomic parameters were comparable between groups (all P > 0.05) including PV and PW characteristics. After 12 months, freedom from AF off antiarrhythmic drug therapy was 51.7% in PVI and 49.7% in PVI+PWI (log-rank P = 0.564). Rapid PW activity was defined as less than the median of the shortest PW cycle length (140 ms) and rapid PV activity was defined as less than the median of the shortest PV cycle length (126 ms). In those with rapid PW activity, the addition of PWI was associated with greater arrhythmia-free survival (56.4%) vs PVI alone (38.6%) (HR: 0.78; 95% CI: 0.67-0.94; log-rank P = 0.030). Moreover, in those undergoing PVI only, the risk of AF recurrence was higher in those with rapid PW activity (55.3% vs 46.5% in slower PW activity; HR: 1.50, 95%CI 1.11-2.26; log-rank P = 0.036). Rapid PV activity and PV cycle length (individual PVs or average of all 4 PVs) were not associated with outcome (all P > 0.05) regardless of ablation strategy. There was no correlation between PW cycle length and posterior low voltage (r = -0.06, P = 0.496). The addition of PWI did not improve arrhythmia-free survival in subgroups with LA enlargement (LA volume index >34 mL/m2) (HR: 0.69; 95% CI: 0.39-1.25; P = 0.301), posterior low-voltage zone (HR: 1.06; 95% CI: 0.68-1.66; P = 0.807), or long-standing PerAF (HR: 1.10; 95% CI: 0.71-1.72; P = 0.669).

CONCLUSIONS

Rapid PW activity is associated with an increased risk of AF recurrence post-catheter ablation. The addition of PWI in this subgroup was associated with a significant improvement in freedom from AF compared with PVI alone. The presence of rapid PW activity may identify patients with PerAF likely to benefit from PWI.

Methods and techniques for increasing the safety and efficacy of pulmonary vein isolation in patients with atrial fibrillation

The most common type of sustained arrhythmia is atrial fibrillation (AF). Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation, which has emerged as the primary therapeutic strategy for atrial fibrillation patients. Unfortunately, about one-third of patients experience recurrent atrial arrhythmias after the procedure.

Holistic Approaches to Arrhythmia Management: Combining Medication, Ablation, and Device Interventions

This narrative review investigates the severe health issue of arrhythmias, which affects millions of people worldwide. A multifaceted strategy incorporating medicine, catheter ablation, and advanced device interventions is necessary to manage these disorders effectively. Medication is the cornerstone, and as antiarrhythmic medications develop, their efficacy and side effects are reduced. Success depends on having individualized treatment strategies that consider patient profiles and arrhythmia type. Catheter ablation, a minimally invasive surgery that targets and removes faulty heart electrical circuits, has become a potent therapy when drugs are ineffective. Technological developments, including high-resolution mapping systems and customized catheters, improve precision. Pacemakers and implantable cardioverter-defibrillators (ICDs) are two examples of implantable cardiac devices essential to managing all types of arrhythmias. Pacemakers provide a regular heartbeat when the body's natural pacing mechanism fails. At the same time, ICDs, with cutting-edge algorithms, can identify and stop life-threatening arrhythmias and offer high-risk patients vital protection. As device technology advances, smaller, more durable devices become available, improving patient comfort and lowering the need for replacements. The seamless fusion of these three strategies is where holistic arrhythmia management shines. Even for difficult instances, customized combination therapy combining medicine, ablation, and device interventions offers complete solutions. Healthcare providers must collaborate for this integrated strategy to deliver personalized, efficient, and holistic care. In conclusion, the management of arrhythmias has developed into a dynamic, synergistic discipline where drugs, catheter ablation, and devices all work in concert to deliver comprehensive care. For those with arrhythmias, a patient-centered strategy that considers their particular patient features and best integrates different modalities can significantly enhance their quality of life. The effectiveness and accessibility of holistic arrhythmia management could be further improved because of ongoing developments in these fields, which is encouraging for patients and medical professionals.

Catheter ablation of atrial fibrillation using FireMagic TrueForce ablation catheter: The TRUEFORCE trial

BACKGROUND

The use of contact force (CF) sensing catheters has provided a revolutionary improvement in catheter ablation (CA) of atrial fibrillation (AF) in the past decade. However, the success rate of CA for AF remains limited, and some complications still occur.

METHODS

The TRUEFORCE trial (Catheter Ablation of Atrial Fibrillation using FireMagic TrueForce Ablation Catheter) is a multicenter, prospective, single-arm objective performance criteria study of AF patients who underwent their first CA procedure using FireMagic TrueForce ablation catheter.

RESULTS

A total of 120 patients (118 with paroxysmal AF) were included in this study, and 112 patients included in the per-protocol analysis. Pulmonary vein isolation (PVI) was achieved in 100% of the patients, with procedure and fluoroscopy time of 146.63 ± 40.51 min and 12.89 ± 5.59 min, respectively. Freedom from recurrent atrial arrhythmia after ablation was present 81.25% (95% confidence interval [CI]: 72.78%-88.00%) of patients. No severe adverse events (death, stroke/transient ischemic attack [TIA], esophageal fistula, myocardial infarction, thromboembolism, or pulmonary vein stenosis) were detected during the follow-up. Four (4/115, 3.33%) adverse events were documented, including one abdominal discomfort, one femoral artery hematoma, one coughing up blood, and one postoperative palpitation and insomnia.

CONCLUSIONS

This study demonstrated the clinical feasibility of FireMagic force-sensing ablation catheter in CA of AF, with a satisfactory short- and long-term efficacy and safety.

A Focal Ablation Catheter Toggling Between Radiofrequency and Pulsed Field Energy to Treat Atrial Fibrillation

BACKGROUND

Because of its safety, "single-shot" pulsed field ablation (PFA) catheters have been developed for pulmonary vein isolation (PVI). However, most atrial fibrillation (AF) ablation procedures are performed with focal catheters to permit flexibility of lesion sets beyond PVI.

OBJECTIVES

This study sought to determine the safety and efficacy of a focal ablation catheter able to toggle between radiofrequency ablation (RFA) or PFA to treat paroxysmal or persistent AF.

METHODS

In a first-in-human study, a focal 9-mm lattice tip catheter was used for PFA posteriorly and either irrigated RFA (RF/PF) or PFA (PF/PF) anteriorly. Protocol-driven remapping was at ∼3 months postablation. The remapping data prompted PFA waveform evolution: PULSE1 (n = 76), PULSE2 (n = 47), and the optimized PULSE3 (n = 55).

RESULTS

The study included 178 patients (paroxysmal/persistent AF = 70/108). Linear lesions, either PFA or RFA, included 78 mitral, 121 cavotricuspid isthmus, and 130 left atrial roof lines. All lesion sets (100%) were acutely successful. Invasive remapping of 122 patients revealed improvement of PVI durability with waveform evolution: PULSE1: 51%; PULSE2: 87%; and PULSE3: 97%. After 348 ± 652 days of follow-up, the 1-year Kaplan-Meier estimates for freedom from atrial arrhythmias were 78.3% ± 5.0% and 77.9% ± 4.1% for paroxysmal and persistent AF, respectively, and 84.8% ± 4.9% for the subset of persistent AF patients receiving the PULSE3 waveform. There was 1 primary adverse event-inflammatory pericardial effusion not requiring intervention.

CONCLUSIONS

AF ablation with a focal RF/PF catheter allows efficient procedures, chronic lesion durability, and good freedom from atrial arrhythmias-for both paroxysmal and persistent AF. (Safety and Performance Assessment of the Sphere-9 Catheter and the Affera Mapping and RF/PF Ablation System to Treat Atrial Fibrillation; NCT04141007 and NCT04194307).

Contact Force-Guided versus Contact Force-Blinded Cavo-Tricuspid Isthmus Ablation for Atrial Flutter: A Systematic Review and Meta-Analysis

Contact force (CF) is a novel approach developed to increase the safety and efficacy of catheter ablation. However, the value of CF-sensing technology for atrial flutter (AFL) cavo-tricuspid isthmus ablation (CTIA) is inconclusive. To generate a comprehensive assessment of optimal extant data on CF for AFL, we synthesized randomized controlled trials (RCTs) and observational studies from Web of Science, SCOPUS, EMBASE, PubMed, and Cochrane until 29 November 2022, using the odds ratio (OR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with a corresponding 95% confidence interval (CI). Two RCTs and three observational studies with a total of 376 patients were included in our analysis. CF-guided ablation was associated with (A) a higher rate of AFL recurrence (OR: 2.26 with 95% CI [1.05, 4.87]) and total CF (MD: 2.71 with 95% CI [1.28, 4.13]); (B) no effect on total procedure duration (MD: -2.88 with 95% CI [-7.48, 1.72]), fluoroscopy duration (MD: -0.96 with 95% CI [-2.24, 0.31]), and bidirectional isthmus block (BDIB) (OR: 1.50 with 95% CI [0.72, 3.11]); and (C) decreased radiofrequency (RF) duration (MD: -1.40 with 95% CI [-2.39, -0.41]). We conclude that although CF-guided CTIA was associated with increased AFL recurrence and total CF and reduced RF duration, it did not affect total procedure duration, fluoroscopy duration, or BDIB. Thus, CF-guided CTIA may not be the optimal intervention for AFL. These findings indicate the need for (A) providers to balance the benefits and risks of CF when utilizing precision medicine to develop treatment plans for individuals with AFL and (B) clinical trials investigating CF-guided catheter ablation for AFL to provide definitive evidence of optimal CF-sensing technology.

Photoplethysmography-documented atrial fibrillation in the first week after catheter ablation is associated with lower success rates

Aims

To test the feasibility of postprocedural photoplethysmography (PPG) rhythm telemonitoring during the first week after atrial fibrillation (AF) ablation and its predictive value for later AF recurrence.

Methods

PPG rhythm telemonitoring during the first week after the ablation procedure was offered to a total of 382 consecutive patients undergoing AF ablation. Patients were instructed to perform 1 min PPG recordings by a mobile health application 3 times per day and in case of symptoms. Clinicians assessed the PPG tracings via a secured cloud and the information was remotely integrated into the therapeutic pathway via teleconsultation (TeleCheck-AF approach).

Results

119 patients (31%) agreed to perform PPG rhythm telemonitoring after ablation. Patients included in the TeleCheck-AF approach were younger compared to those who declined participation (58 ± 10 vs. 62 ± 10 years, p < 0.001). Median follow up duration was 544 (53-883) days. 27% of patients had PPG tracings suggestive of AF in the week following the ablation. In 24% of patients, the integration of PPG rhythm telemonitoring resulted in a remote clinical intervention during teleconsultation. During follow-up of one year, 33% of patients had ECG-documented AF recurrences. PPG recordings suggestive of AF in the week after ablation were predictive of late recurrences (p < 0.001).

Conclusion

PPG rhythm telemonitoring during the first week after AF ablation often triggered clinical interventions. Due to its high availability, PPG-based follow-up actively involving patients after AF ablation may close a diagnostic and prognostic gap in the blanking period and increase active patient-involvement.

Efficiency and safety of high-power ablation guided by Lesion size index: An ex vivo porcine heart study

BACKGROUND

Although Lesion size index (LSI) has been reported to highly predict radiofrequency lesion size in vitro, its accuracy in lesion size and steam pop estimation has not been well investigated for every possible scenario.

METHODS

Initially, radiofrequency ablations were performed on porcine myocardial slabs at various power, CF, and time settings with blinded LSI. Subsequently, radiofrequency power at 20, 30, 40, 50, and 60 W was applied at CF values of 5, 10, 20, and 30 g to reach target LSIs of 4, 5, 6, and 7. Lesion size and steam pops were recorded for each ablation.

RESULTS

Lesion size was positively correlated with LSI regardless of power settings (p < 0.001). The linear correlation coefficients of lesion size and LSI decreased at higher power settings. At high power combined with high CF settings (50 W/20 g), lesion depth and LSI showed an irrelevant correlation (p = 0.7855). High-power ablation shortened ablation time and increased the effect of resistive heating. LSI could predict the risk of steam pops at high-power settings with the optimal threshold of 5.65 (sensitivity, 94.1%; specificity, 46.1%). The ablation depth of the heavy heart was shallower than that of the light heart under similar ablation settings.

CONCLUSIONS

LSI could predict radiofrequency lesion size and steam pops at high power settings in vitro, while synchronous high power and high CF should be avoided. Lighter hearts require relatively lower ablation settings to create appropriate ablation depth.

Standard vs Augmented Ablation of Paroxysmal Atrial Fibrillation for Reduction of Atrial Fibrillation Recurrence: The AWARE Randomized Clinical Trial

Importance

Recurrent atrial fibrillation (AF) commonly occurs after catheter ablation and is associated with patient morbidity and health care costs.

Objective

To evaluate the superiority of an augmented double wide-area circumferential ablation (WACA) compared with a standard single WACA in preventing recurrent atrial arrhythmias (AA) (atrial tachycardia, atrial flutter, or atrial fibrillation [AF]) in patients with paroxysmal AF.

Design, Setting, and Participants

This was a pragmatic, multicenter, prospective, randomized, open, blinded end point superiority clinical trial conducted at 10 university-affiliated centers in Canada. The trial enrolled patients 18 years and older with symptomatic paroxysmal AF from March 2015 to May 2017. Analysis took place between January and April 2022. Analyses were intention to treat.

Interventions

Patients were randomized (1:1) to receive radiofrequency catheter ablation for pulmonary vein isolation with either a standard single WACA or an augmented double WACA.

Main Outcomes and Measures

The primary outcome was AA recurrence between 91 and 365 days postablation. Patients underwent 42 days of ambulatory electrocardiography monitoring after ablation. Secondary outcomes included need for repeated catheter ablation and procedural and safety variables.

Results

Of 398 patients, 195 were randomized to the single WACA (control) arm (mean [SD] age, 60.6 [9.3] years; 65 [33.3%] female) and 203 to the double WACA (experimental) arm (mean [SD] age, 61.5 [9.3] years; 66 [32.5%] female). Overall, 52 patients (26.7%) in the single WACA arm and 50 patients (24.6%) in the double WACA arm had recurrent AA at 1 year (relative risk, 0.92; 95% CI, 0.66-1.29; P = .64). Twenty patients (10.3%) in the single WACA arm and 15 patients (7.4%) in the double WACA arm underwent repeated catheter ablation (relative risk, 0.72; 95% CI, 0.38-1.36). Adjudicated serious adverse events occurred in 13 patients (6.7%) in the single WACA arm and 14 patients (6.9%) in the double WACA arm.

Conclusions and Relevance

In this randomized clinical trial of patients with paroxysmal AF, additional ablation by performing a double ablation lesion set did not result in improved freedom from recurrent AA compared with a standard single ablation set.

Trial Registration

ClinicalTrials.gov Identifier: NCT02150902.

Impact of Catheter Ablation on Cognitive Function in Atrial Fibrillation: A Randomized Control Trial

BACKGROUND

Early postoperative cognitive dysfunction (POCD) has been reported following atrial fibrillation (AF) ablation. However, whether POCD is persistent long-term is unknown.

OBJECTIVES

The purpose of this study was to determine if AF catheter ablation is associated with persistent cognitive dysfunction at 12-month follow-up.

METHODS

This is a prospective study of 100 patients with symptomatic AF who failed at least 1 antiarrhythmic drug randomized to either ongoing medical therapy or AF catheter ablation and followed up for 12 months. Changes in cognitive performance were assessed using 6 cognitive tests administered at baseline and during follow-up (3, 6, and 12 months).

RESULTS

A total of 96 participants completed the study protocol. Mean age was 59 ± 12 years (32% women, 46% with persistent AF). The prevalence of new cognitive dysfunction in the ablation arm compared with the medical arm was as follows: at 3 months: 14% vs 2%; P = 0.03; at 6 months: 4% vs 2%; P = NS; and at 12 months: 0% vs 2%; P = NS. Ablation time was an independent predictor of POCD (P = 0.03). A significant improvement in cognitive scores was seen in 14% of the ablation arm patients at 12 months compared with no patients in the medical arm (P = 0.007).

CONCLUSIONS

POCD was observed following AF ablation. However, this was transient with complete recovery at 12-month follow-up.

Safety and efficacy of direct oral anticoagulation in patients with and without radiofrequency ablation of non-valvular atrial fibrillation: a multicenter retrospective cohort study

BACKGROUND

Based on the few available studies on the prognostic benefit of using direct oral anticoagulants (DOACs) after atrial fibrillation (AF) ablation. Therefore, this study aimed to evaluate the prognostic differences between patients who underwent radiofrequency ablation (RFA) and those without RFA taking DOACs.

METHODS

This is a multicenter retrospective cohort study enrolling 6137 patients with non-valvular AF (NVAF) at 15 hospitals in China. Patient information was collected through a mean follow-up of 10 months and medical record queries. Clinical outcomes included major bleeding, total bleeding, thrombosis, all-cause death, and a composite endpoint of bleeding, thrombosis, and all-cause death.

RESULTS

After adjusting for confounders and propensity score matching (PSM), patients with RFA of NVAF had a significantly lower risk of major bleeding [OR 0.278 (95% CI, 0.150-0.515), P<0.001], thrombosis [OR 0.535 (95% CI, 0.316-0.908), P=0.020] and the composite endpoint [ OR 0.835 (95% CI, 0.710-0.982), P=0.029]. In the RFA PSM cohort, dabigatran was associated with reduced all-cause death in patients with RFA of NVAF [OR 0.420 (95% CI, 0.212-0.831), P=0.010]. In the no RFA PSM cohort, rivaroxaban was associated with a reduction in major bleeding [OR 0.521 (95% CI, 0.403-0.673), P<0.001], total bleeding [OR 0.114 (95% CI, 0.049-0.266), P<0.001], and the composite endpoint [OR 0.659 ( 95% CI, 0.535-0.811), P<0.001].

CONCLUSION

Among patients with NVAF treated with DOACs, RFA was a negative correlate of major bleeding, thrombosis, and composite endpoints but was not associated with total bleeding or all-cause mortality.

Major drivers of healthcare system costs and cost variability for routine atrial fibrillation ablation

Background

Catheter ablation is an effective treatment for atrial fibrillation (AF) but incurs significant financial costs to payers. Reducing variability may improve cost effectiveness.

Objectives

We aimed to measure (1) the components of direct and indirect costs for routine AF ablation procedures, (2) the variability of those costs, and (3) the main factors driving ablation cost variability.

Methods

Using data from the University of Utah Health Value Driven Outcomes system, we were able to measure direct, inflation-adjusted costs of uncomplicated, routine AF ablation to the healthcare system. Direct costs were considered costs incurred by pharmacy, disposable supplies, patient labs, implants, and other services categories (primarily anesthesia support) and indirect costs were considered within imaging, facility, and electrophysiology lab management categories.

Results

A total of 910 patients with 1060 outpatient ablation encounters were included from January 1, 2013, to December 31, 2020. Disposable supplies accounted for the largest component of cost with 44.8 ± 9.7%, followed by other services (primarily anesthesia support) with 30.4 ± 7.7% and facility costs with 16.1 ± 5.6%; pharmacy, imaging, and implant costs each contributed <5%. Direct costs were larger than indirect costs (82.4 ± 5.6% vs 17.6 ± 5.6%). Multivariable regression showed that procedure operator was the primary factor associated with AF ablation overall cost (up to 12% differences depending on operator).

Conclusions

Direct costs and other services (primarily anesthesia) drive the majority costs associated with AF ablations. There is significant variability in costs for these routine, uncomplicated AF ablation procedures. The procedure operator, and not patient characteristic, is the main driver for cost variability.

A Novel Catheter Distal Contact Force Sensing for Cardiac Ablation Based on Fiber Bragg Grating with Temperature Compensation

OBJECTIVE

To accurately achieve distal contact force, a novel temperature-compensated sensor is developed and integrated into an atrial fibrillation (AF) ablation catheter.

METHODS

A dual elastomer-based dual FBGs structure is used to differentiate the strain on the two FBGs to achieve temperature compensation, and the design is optimized and validated by finite element simulation.

RESULTS

The designed sensor has a sensitivity of 90.5 pm/N, resolution of 0.01 N, and root-mean-square error (RMSE) of 0.02 N and 0.04 N for dynamic force loading and temperature compensation, respectively, and can stably measure distal contact forces with temperature disturbances.

CONCLUSION

Due to the advantages, i.e., simple structure, easy assembly, low cost, and good robustness, the proposed sensor is suitable for industrial mass production.

The impact of the procedural parameters on the lesion characteristics associated with AF recurrence: Late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) analysis

BACKGROUND

Lesion gaps assessed by late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) are associated with the atrial fibrillation (AF) recurrence after pulmonary vein isolation. Animal studies have demonstrated that the catheter-contact force (CF), stability, and orientation are strongly associated with lesion formation. However, the impact of those procedural factors on the lesion characteristics associated with AF recurrence has not been well discussed.

METHODS

A total of 30 patients with paroxysmal AF who underwent catheter ablation were retrospectively enrolled. Radiofrequency (RF) applications were performed with 35 W for 30 s in a point-by-point fashion under esophageal temperature monitoring. The inter-lesion distance was 4 mm. The lesions were visualized by LGE-MRI 3 months postprocedure and assessed by the LGE volume (ml), gap number (GN), and average gap length (AGL [mm]). The gaps were defined as nonenhancement sites of >4 mm. The procedural factors including the catheter-CF, stability, and orientation were calculated on the NavX system.

RESULTS

Six (20%) of 30 patients had AF recurrences 12 months postablation. A univariate analysis demonstrated that the AGL was associated with AF recurrence (hazard ratio [HR]: 1.20, confidence interval [CI]: 1.03-1.42, p = .02). All AF recurrence were found in patients with an AGL of >7 mm. The catheter-CF and stability were associated with an AGL of >7 mm, but not the orientation (CF-HR: 0.62, CI: 0.39-0.97, p = .038; stability-HR: 0.8, CI: 0.66-0.98, p = .027).

CONCLUSIONS

RF ablation with a low CF and poor catheter stability has a potential risk of creating large lesion gaps associated with AF recurrence.

Clinical outcome of lesion size index-guided high-power radiofrequency catheter ablation for pulmonary vein isolation in patients with atrial fibrillation: 2-year follow-up

INTRODUCTION

The long-term efficacy of high-power (50 W) ablation guided by lesion size index (LSI-guided HP) for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) remains undetermined. Our study sought to assess the clinical efficacy of LSI-guided HP ablation for PVI in patients with AF and explore the potential predictors associated with clinical outcomes.

METHODS

We consecutively included 186 patients with AF who underwent LSI-guided HP (50 W) ablation at Fuwai Hospital from June 2019 to October 2021. The target LSI values of 4.5-5.5 and 4.0-4.5 at the anterior and posterior walls, respectively, were used in our study. The baseline clinical characteristics, procedural and ablation data, and clinical outcomes were evaluated. The independent potential predictors associated with AF recurrence were further evaluated.

RESULTS

The incidence rate of first-pass PVI was 83.9% (156/186). A total of 11 883 lesions were analyzed, and compared with posterior walls of pulmonary veins, anterior walls had significantly lower mean contact force (8.2 ± 3.0 vs. 8.3 ± 2.3 g, p = .015), longer mean radiofrequency duration (16.9 ± 7.2 vs. 12.9 ± 4.5 s, p < .001) and higher mean LSI (4.8 ± 0.2 vs. 4.4 ± 0.2, p < .001). The overall incidence of periprocedural complications was 3.7%, and steam pops without pericardial effusion occurred in three patients (1.6%). During a mean follow-up of 24.0 ± 8.4 months, the overall AF recurrence-free survival was 87.1% after a single procedure. Patients with paroxysmal AF had a higher incidence of freedom from AF recurrence than those with persistent AF (91.2% vs. 80.8%, log-rank p = .034). Higher LSI (HR 0.50, p < .001) and paroxysmal AF (HR 0.39, p = .029) were significantly associated with decreased AF recurrence. By receiver operating characteristic analysis, the LSI of 4.7 and 4.3 for the anterior and posterior walls of the PVs had the highest predictive value for AF recurrence, respectively.

CONCLUSION

LSI-guided HP (50 W) ablation for PVI was an efficient and safe strategy and led to favorable single-procedure 2-year AF recurrence-free survival in patients with AF. Higher LSI and paroxysmal AF were independent predictors of decreased 2-year AF recurrence. The LSI of 4.7 for the anterior wall and 4.3 for the posterior wall of the PVs were the best cutoff values for predicting AF recurrence after LSI-guided HP ablation.