Ablation Strategy For Atrial Fibrillation Research Articles

Abstract 4137964: Electrical Gaps and Outcomes After Redo AF Ablation: Comparative Analysis from the EARNEST-PVI Trial

Introduction: The efficacy of extensive ablation strategies in addition to pulmonary vein (PV) isolation is still controversial in persistent atrial fibrillation (AF) ablation. Gaps in previously ablated lesions can induce arrhythmias, potentially decreasing the effectiveness of extensive ablation. Purpose: To evaluate the incidence of gaps, gap-related reentry, and subsequent recurrence following redo AF ablation in the EARNEST-PVI trial (NCT03514693). Methods: The analysis was performed using the extended data of the EARNEST-PVI trial (N=512), a randomized controlled trial evaluating ablation strategies for persistent AF. Patients were randomized 1:1 to either the PVI-plus or PVI-alone group. During a median follow-up of 47 months, 126 (25%) patients underwent redo AF ablation. Among them, we enrolled patients who underwent PVI-alone (N=69), or PVI-plus left atrial (LA) linear ablations (LA roof and mitral isthmus) (N=46) during the index ablation. Results: In the previous PVI-alone group, electrical PV gaps were observed in 38 (57%) patients. In the previous PVI-plus group, 19 (41%), 10 (22%), and 11 (24%) patients had electrical gaps in the PVs, LA linear lines, or both, respectively. During the redo session, 19 atrial tachycardias (ATs) were observed/induced in 15 patients. ATs were more frequently observed in the PVI-plus group than in the PVI-alone group (23.9% vs. 5.8%, p=0.005). While 7 ATs were not associated with gaps, 2 were related to PV gaps, and 10 were related to gaps in the linear lesions. In the redo AF ablation, PVI was re-completed in all patients, and any induced ATs were eliminated by additional ablation. During a median follow-up of 32 months post-redo, patients with gaps had a lower clinical recurrence rate than those without (44.3 vs. 47.2%, log-rank p=0.033). However, the Cox regression analysis revealed that AF recurrence post-redo was associated only with PV gaps, and not with linear ablation gaps (hazard ratio, 0.57; 95% confidence interval, 0.32–0.99; p = 0.049). Conclusions: In redo AF ablations, electrical gaps were more prevalent in patients who underwent extensive ablation during the index procedure. While all gaps during redo were potentially arrhythmogenic, PV gaps alone were associated with AF recurrence after redo AF ablation.

Arrhythmia

The basic principles of atrial fibrillation(AF)treatment are stroke prevention with appropriate anticoagulation, rhythm and rate control with drugs, and non-pharmacological therapy. The current guidelines have been presented. Non-pharmacological treatment(catheter ablation)for AF, originally developed to eliminate motivational symptoms, has been shown to improve life outcomes, and indications for ablation are expanding rapidly. Catheter ablation has evolved remarkably from conventional radiofrequency to balloon ablation. Minimal complications are expected to occur with pulsed-field ablation. Ablation strategies for paroxysmal AF are almost established and approaches for persistent AF are becoming increasingly important. Surgical approaches have also evolved significantly, with robotic surgery, the thoracoscopic Wolf-Ohtsuka procedure, and minimally invasive cardiac surgery, becoming less invasive. Future studies should prioritize a system for better function and treatment options for the heart team.

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

Abstract Background Cardiac ablation is a well-established treatment option for preventing atrial fibrillation (AF). While radiofrequency, cryo-energy, and laser energies are commonly employed in catheter ablation, they present the risk of potential damage to adjacent organs such as the oesophagus and phrenic nerve. To address these concerns, new technologies are being explored including pulsed field ablation (PFA), a non-thermal energy approach that employs high-voltage, short-duration pulses to selectively destroy target cells. Purpose The present analysis aims at: i) quantifying the short-term costs related to three ablation strategies for paroxysmal AF (PFA, radiofrequency ablation -RFA-, and cryo-balloon ablation -CRYO-), identify the cost drivers, and assess potential variations in resource consumption for each treatment alternative; ii) comparing the medium-term (1-year) economic implications of adopting the three alternatives, in terms of redo procedures (effectiveness) and complications (safety). Methods A cost-consequence model was developed to compare economic outcomes of the three ablation strategies for paroxysmal AF in the short- (during procedure) and medium-term (1-year). Resource consumption data during the procedure were collected by two European medical centres specialized in cardiac ablation (N=61 patients). For the medium-term analysis, costs were correlated to the effectiveness and safety of the procedures. The clinical data (i.e., redo and complication rates) considered in the model were retrieved from published literature. Costs and tariffs were collected from economic formularies of the respective hospitals. A scenario analysis was conducted to evaluate economic outcomes under various hypothetical difference in the prices of treatment kits. Results A significant difference was registered in terms of pre-procedural (mean±SD: 13.9±4.4 min for PFA, 20.1±7.6 min for CRYO and 20.5±7.7 min for RFA; ANOVA test p=0.003) and procedural time (skin-to-skin), favouring PFA over RFA and CRYO (53.6±26.8 min for PFA, 72.4±28.1 min for CRYO and 149.9±99.9 min for RFA; p<0.0001; Table 1). PFA was associated with lower procedural costs vs CRYO (-€400) and RFA (-€827). A similar economic advantage was observed in the medium-term (Table 2). The scenario analysis showed that PFA would be cost-saving vs CRYO (Δtotal costs ≤ 0) up to a price difference of +€881 (i.e., PFA kit is more expensive than CRYO kit), and similarly, up to a price difference of +€1,306 vs RFA. Above these thresholds, PFA would be considered cost-effective vs CRYO or RFA, due to its efficacy despite being more expensive. Conclusion In summary, PFA emerges as cost-effective or even cost-saving over CRYO and RFA, thanks to its faster execution, lower redo, and complications rate. Moreover, PFA time predictability would facilitate hospital planning. For a complete analysis, these benefits should be evaluated against the difference in acquisition costs among treatments.Procedural time by phase and techniqueCumulative savings per technique

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.

Assessing the arrhythmogenic propensity of fibrotic substrate using digital twins to inform a mechanisms-based atrial fibrillation ablation strategy

Atrial fibrillation (AF), the most common heart rhythm disorder, may cause stroke and heart failure. For patients with persistent AF with fibrosis proliferation, the standard AF treatment—pulmonary vein isolation—has poor outcomes, necessitating redo procedures, owing to insufficient understanding of what constitutes good targets in fibrotic substrates. Here we present a prospective clinical and personalized digital twin study that characterizes the arrhythmogenic properties of persistent AF substrates and uncovers locations possessing rotor-attracting capabilities. Among these, a portion needs to be ablated to render the substrate not inducible for rotors, but the rest (37%) lose rotor-attracting capabilities when another location is ablated. Leveraging digital twin mechanistic insights, we suggest ablation targets that eliminate arrhythmia propensity with minimum lesions while also minimizing the risk of iatrogenic tachycardia and AF recurrence. Our findings provide further evidence regarding the appropriate substrate ablation targets in persistent AF, opening the door for effective strategies to mitigate patients’ AF burden.

Strategies for recurrent atrial fibrillation in patients despite durable pulmonary vein isolation

Abstract Background Pulmonary vein isolation (PVI) is the cornerstone in treatment of atrial fibrillation (AF). Despite initially successful PVI patients experience recurrence of AF mostly due to reconnection of pulmonary veins (PVs). However, a certain number of patients presents with recurrent AF despite durable PVI. The optimal ablation strategy for these patients has yet to be discerned. Aim The aim of this study was to compare outcomes for different ablation strategies for recurrent AF despite persistent PVI. Methods All redo procedures for recurrence of AF from 01/2016 – 6/2022 at our center were analyzed. Only patients with proven durable PVI (entrance/exit block and high density (HD) mapping) were included. Patients were excluded, if re-PVI or right atrial ablation was necessary. In all procedures (HD) 3-D mapping and radiofrequency ablation were performed. Ablation strategy was at operators’ discretion. A 12-month follow up (FU) was obtained. Results A total of 405 left-atrial procedures for the recurrence of AF were analyzed. In 85 (21.0%) procedures all PVs were still isolated. Of these 30 patients (35.3 %) were female and 70 patients (82.4 %) suffered from persistent AF. In 49 patients (57.6 %) LA scar was detectable (85.7 % persAF). The ablation strategies consisted of: roof line (n=9; 10.6 %), left atrial anterior line (n=8, 9.4 %), roof line and left atrial anterior line (n=8, 9.4%), roof line and left atrial inferior line (n=18, 21.2 %), box lesion (n=6, 7.1 %), other left atrial ablation lines (n=20, 23.5 %) and substrate modification (CFAE and substrate encirclement) (n=16, 18.8 %). In patients with PAF (n=15), 3 patients received a roof line (20.0 %), 3 patients received the latter and left atrial inferior line (20.0 %), 5 patients received other left atrial ablation lines (33.3 %) and 4 patients received substrate modification (CFAE and substrate encirclement) (26.7 %). After a mean follow up of 401 +/- 125 days 55.3 % (n=47) of patients were free from any atrial arrhythmia (roof line 77.8 +/- 15 %, left atrial anterior line 87.5 +/- 13 %, roof line and left atrial anterior line 37.5 +/- 18 %, roof line and left atrial inferior line 50 +/- 12 %, box lesion 83.3 +/- 17 %, other left atrial ablation lines 45.0 +/- 11 %, substrate modification (CFAE and substrate encirclement) 43.8 +/- 13 %, p=0.122), 35.3 % (n=30) showed recurrence of AF (p=0.287) and 9.4 % (n=8) showed atrial tachycardia (AT) (p=0.693). None of the ablation strategies led to a significantly superior outcome. Conclusion In patients suffering from recurrence of AF despite durable pulmonary vein isolation different substrate modification strategies did not show any superiority for one or the other. Despite the necessity of additional ablation beyond PVI the optimal ablation strategy needs to be yet determined to improve outcome for redo procedures.

A multicenter evaluation of repeat ablation for atrial fibrillation in patients with isolated pulmonary veins: a Netherlands Heart Registration study

Abstract Background Of the 25-50% atrial fibrillation (AF) ablation patients who undergo repeat ablation, approximately 15-30% have all pulmonary veins (PVs) isolated at the repeat procedure. Currently, there is limited evidence and a lack of consensus on the appropriate treatment strategy for patients with isolated PVs. Purpose Our aim was to characterize and compare the effectiveness of repeat AF ablation strategies to reduce AF recurrences in patients with isolated PVs using a real-world multicenter registry. Methods All AF patients referred for repeat AF ablation with all PVs isolated at 8 hospitals in the Netherlands were included (Netherlands Heart Registration; 2016-2019). Medical record reviews were conducted for all patients referred for repeat AF ablation to determine study eligibility, the presence of PV reconnection, ablation strategy used, and the outcome of AF recurrence. Patients referred for repeat AF ablation, with PVI only conducted during previous ablations, and all PVs isolated were eligible. Effectiveness of repeat AF ablation strategies were assessed with multivariable Cox models comparing individual ablation strategies, number of ablation strategies performed, and presence of persistent AF. Results Of 2,311 repeat AF ablations performed, 274 (11.9%) were eligible and had all PVs isolated (Figure 1). Patients with isolated PVs were a median age of 66 (IQR 58-70) years, 44.2% were women, 45.6% had persistent or long-standing persistent AF, and the median CHA2DS2-Vasc score was 2 (IQR 1-3). Ablation was not performed in 33 (12.0%) patients with isolated PVs (Figure 2a). A single ablation strategy was performed most often (41.2%; Figure 2a). Posterior box ablation was the most frequent (58.4%) ablation strategy performed, followed by antralization of the PVs (26.3%). Over a median follow-up of 2.0 (1.0-3.3) years, 147 (59.8%) patients with isolated PVs had an AF recurrence &amp;gt;3 months after repeat ablation and 30 (12.7%) patients had another repeat AF ablation within 1 year of repeat procedure. After multivariable adjustment, no difference in AF recurrences was detected between ablation strategies [p&amp;gt;0.05 for all; Figure 2b]. Further, there was no difference detected in AF recurrences for the number of ablation strategies performed (Figure 2c), the individual ablation strategy conducted, and persistent AF (p&amp;gt;0.05 for all). Among patients with isolated PVs, patients with larger left atrial size had a higher risk of AF recurrences [adjusted HR 1.03 (95% CI 1.01-1.05)]. Conclusion Among the 2,311 repeat AF ablations performed, 11.9% had all PVs isolated. Despite multiple ablation strategies performed for isolated PVs, 59.8% of patients had an AF recurrence over follow-up and no difference in the incidence of AF recurrences was detected between repeat ablation strategies. Further evidence is warranted to determine an effective treatment strategy to reduce AF recurrences in AF patients with isolated PVs.

Atrial Functional Substrates for the Prediction of Atrial Fibrillation Recurrence After Pulmonary Vein Isolation

Low-voltage areas have been used as atrial structural substrates in estimating fibrotic degeneration in patients with atrial fibrillation (AF). The high-resolution maps obtained by recently developed mapping catheters allow the visualization of several functional abnormalities. We investigated the association between left atrial (LA) functional abnormal findings on a high-resolution substrate map and AF recurrence in patients who underwent pulmonary vein isolation without any additional LA substrate ablation. This observational study included 100 consecutive patients who underwent second ablation for AF (paroxysmal, 48%; persistent, 52%). Patients with extra-pulmonary-vein LA substrate ablation during the initial and second ablation were excluded. LA mapping was performed using a 64-pole mini-basket catheter on the Rhythmia mapping system. Patients were followed for 2 years. AF recurrence developed in 39 (39%) patients. On the high-resolution substrate map, AF recurrence was associated with the presence of the following findings: low-voltage areas (<1.0 mV, >5cm2; hazard ratio [HR]=2.53; 95% confidence interval [CI]=1.30-4.93; p<0.006), fractionated-electrogram areas (≥5 peaks, >5cm2; HR=2.15, 95%CI=1.10-4.19; p=0.025), LA conduction time of >130 msec (HR=3.11, 95%CI=1.65-5.88, p<0.0001), deceleration zone (≥5 isochrones/cm2; HR=1.97, 95%CI=1.04-3.37, p=0.039), and multiple septal breakout points (HR=3.27, 95%CI=1.50-7.16, p=0.003). Accumulation of these risk factors increased AF recurrence in a stepwise manner, with an HR=1.90, 95%CI=1.44-2.52, p<0.00001 for each additional risk factor. In conclusion, high-resolution map revealed new LA functional substrates associated with AF recurrence. Implementation of functional substrates may improve the prediction of AF recurrence after ablation, and possibly aid the development of tailored AF ablation strategies.

Evaluation of the effectiveness and safety of a novel substrate-based radiofrequency ablation for persistent atrial fibrillation: a prospective, randomised, parallel-controlled, single-blinded study protocol

IntroductionPulmonary vein isolation (PVI) is the cornerstone of radiofrequency (RF) ablation for atrial fibrillation (AF). However, a single ablation strategy does not always achieve the desired therapeutic effect in all...

Abstract 11697: Combined-Energy Pulmonary Vein Isolation and Posterior Wall Isolation for Persistent Atrial Fibrillation: Results of a 3-year Follow-Up

Introduction: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for paroxysmal atrial fibrillation (AF), but the optimal ablation strategy for persistent AF (PsAF) remains controversial. Hypothesis: The purpose of this study was to investigate whether combined-energy cryoballoon (CB) PVI and radiofrequency (RF) left atrial posterior wall isolation (LAPWI) at index ablation of PsAF yields higher success than PVI alone. Methods: Patients with persistent AF (n = 186) who underwent catheter ablation between 2016 and 2019 at a single large academic medical center were retrospectively reviewed. Patients with congenital heart disease or prior left atrial ablation or surgery were excluded. Combined-energy ablation (n=92) consisted of CB antral PVI followed by RF roof and floor lines to achieve LAPWI, along with isolation inside the box as needed. The control group had PVI only (n=94) with either CB (n=57) or RF (n=37). The primary endpoint was 12-, 24-, and 36-month freedom from any documented atrial tachyarrhythmia over 30 seconds after a 90-day blanking period following catheter ablation, compared by Kaplan-Meier analysis. Secondary endpoints included AF burden, procedural parameters, and complications. Results: The primary endpoint of 12-month freedom from any atrial tachyarrhythmia was higher for the combined-energy group vs the control group (79.1% vs 58.2%, p = 0.009). This improvement was sustained at 24 months (63.0% vs 45.8%) and at 36 months (60.3% vs 43.1%) and remained significant after adjustment for clinical covariates (adjusted HR 0.45, 95% confidence interval 0.22-0.95; p = 0.03). There was no significant difference in procedure time or complication rates, however fluoroscopy time was shorter with combined-energy ablation (p&lt;.001). Conclusions: In this single center experience, combined-energy CB-PVI and RF-LAPWI was associated with reduced AF recurrence compared to PVI with a single energy source.

Effective superior vena cava isolation using a novel C-shaped approach.

Superior vena cava (SVC) isolation has been proposed as part of the ablation strategy for atrial fibrillation. However, circumferential isolation of the SVC can lead to late-onset complications, such as SVC stenosis. We describe a detailed observation of the SVC conduction pattern and present a newly developed approach for SVC isolation that involves creating a C-shaped non-circumferential ablation line while sparing the lateral segment. Twelve consecutive patients were included in the study, all of whom achieved bidirectional block during the ablation procedure. This approach to SVC isolation is effective and has the potential to reduce ablation related complications; however, larger studies and long-term follow-up is warranted to confirm these findings.

Antiarrhythmic Drugs vs. Ablation for Atrial Fibrillation

Summary:&#x0D; Atrial fibrillation (AF) is a common and potentially life-threatening cardiac arrhythmia that affects millions of individuals worldwide. The treatment landscape for AF has traditionally comprised antiarrhythmic drugs (AADs), which aim to restore and maintain normal heart rhythm. However, over the past two decades, catheter ablation has emerged as an alternative therapeutic approach in the management of AF. This article systematically compares the effectiveness, safety, and long-term outcomes of AADs and catheter ablation as treatment strategies for atrial fibrillation.&#x0D; Introduction:&#x0D; Atrial fibrillation (AF) is characterized by disorganized electrical activity in the atria, causing irregular and often rapid heart rhythm. Over the years, pharmacological therapy with antiarrhythmic drugs (AADs) has been the mainstay of AF treatment. Nonetheless, catheter ablation has gained significant momentum due to its ability to directly target the arrhythmogenic substrate within the heart.1&#x0D; Efficacy:&#x0D; &#x0D; Antiarrhythmic Drugs: Various classes of AADs inhibit specific ion channels or receptors to normalize cardiac electrical conduction. While AADs can effectively restore sinus rhythm in many patients, their long-term success in maintaining sinus rhythm is modest, with recurrence rates ranging from 40% to 60% within one year.2&#x0D; Catheter Ablation: Ablation procedures selectively target and destroy the abnormal electrical pathways contributing to AF. In well-selected patients, catheter ablation has demonstrated higher efficacy rates than AADs, particularly in paroxysmal AF, with success rates reaching 70-80% or more after a single procedure.2&#x0D; &#x0D; Safety Profile:&#x0D; &#x0D; Antiarrhythmic Drugs: Although generally well-tolerated, AADs have notable adverse effects, including pro-arrhythmia, organ toxicity, and drug-drug interactions. These side effects often limit their usage or require careful patient monitoring.3&#x0D; Catheter Ablation: While catheter ablation is generally safe, it has a finite risk of procedural complications, such as vascular injury, cardiac perforation, and stroke. Nonetheless, the overall complication rate is low, ranging from 1% to 5%, and is further decreasing with advancements in technology and operator experience.3&#x0D; &#x0D; Quality of Life and Symptom Control:&#x0D; &#x0D; Antiarrhythmic Drugs: Effective rate control with AADs can significantly improve symptom burden and quality of life in patients with persistent or permanent AF.4&#x0D; Catheter Ablation: Successful ablation procedures can offer long-term freedom from AF symptoms, eliminating or reducing the dependence on AADs and their associated side effects.4&#x0D; &#x0D; Long-Term Outcomes:&#x0D; &#x0D; Antiarrhythmic Drugs: AAD therapy is often lifelong, and patients may require multiple medication adjustments due to loss of efficacy or intolerable side effects. However, AADs remain a treatment option for patients with contraindications for ablation or in those who prefer medical management.4&#x0D; Catheter Ablation: Successful ablation procedures have been associated with excellent long-term outcomes, with sustained freedom from AF achieved in approximately 60-70% of patients at 1-5 years of follow-up. Repeat ablations may be necessary in some cases.4&#x0D; &#x0D; Conclusion:&#x0D; While both antiarrhythmic drugs and catheter ablation have their advantages and disadvantages in the management of atrial fibrillation, catheter ablation has emerged as a promising treatment strategy, offering higher success rates and long-term symptom control compared to AADs. However, individual patient characteristics, preferences, and comorbidities should guide the selection of the optimal treatment approach, ensuring personalized and comprehensive management of atrial fibrillation. Further research is needed to refine patient selection criteria, improve ablation techniques, and optimize the use of antiarrhythmic drugs to enhance treatment outcomes for AF patients.&#x0D; References&#x0D; &#x0D; Asad ZUA, Yousif A, Khan MS, Al-Khatib SM, Stavrakis S. Catheter Ablation Versus Medical Therapy for Atrial Fibrillation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Circ Arrhythm Electrophysiol. 2019;12(9):e007414.&#x0D; Andrade JG, Deyell MW, Macle L, Wells GA, Bennett M, Essebag V, et al. EARLY-AF Investigators. Progression of Atrial Fibrillation after Cryoablation or Drug Therapy. N Engl J Med. 2023;388(2):105-16.&#x0D; Charitakis E, Metelli S, Karlsson LO, Antoniadis AP, Rizas KD, Liuba I, et al. Comparing efficacy and safety in catheter ablation strategies for atrial fibrillation: a network meta-analysis. BMC Med. 2022;20(1):1-3.&#x0D; Deshpande R, AlKhadra Y, Singanallur P, Botchway A, Labedi M. Outcomes of catheter ablation versus antiarrhythmic therapy in patients with atrial fibrillation: a systematic review and meta-analysis. J Interv Card Electrophysiol. 2022;65(3):773-802.&#x0D;

Reassessment of the electrical connection between the pulmonary veins and the left atrium: A study to determine the different contributions of myocardial fibers along the standard ablation circumference.

Circumferential ablation around the ipsilateral pulmonary veins (PVs) is the standard strategy for atrial fibrillation ablation. The present study seeks to assess which regions of the standard ablation circumference are the main contributors to the venoatrial electrical connection. A total of 41 patients were included under a specific atrial fibrillation ablation protocol in which the anterior and posterior segments of the standard circumference, between the equatorial line of the superior and the inferior ipsilateral PVs, were ablated first. If PV isolation was not achieved, ablation was extended superiorly or inferiorly, on the basis of the earliest atrial activation recorded during pacing from inside the PV. Complete PV isolation and the length of the areas not requiring ablation (ANRA) at the time of electrical isolation were evaluated. Ablation of the anterior and posterior segments of the standard circumference led to the isolation of 77% left-PV pairs and 51% right-PV pairs (p = 0,015). A superior extension was required in 23% left-PV pairs and in 46% right-PV pairs, while an inferior extension was required only in 10% left-PV pairs and in 11% right-PV pairs. PV isolation was achieved before completing the standard ablation circumference in 97% left-PV pairs and in 94% right-PV pairs, with a median ANRA of 36.9 (IQR: 30.9-42.1) mm in the left PVs [16.0 (IQR: 12.0-19.0) mm superior and 18.8 (IQR: 16.1-24.9) mm inferior, p < 0.01] and 36.9 (IQR: 30.2-41.0) mm in the right PVs [15.1 (IQR: 10.7-19.1) mm superior and 20.6 (IQR: 16.9-23.3) mm inferior, p < 0.01]. The myocardial fibers along the anterior and posterior regions of the standard ablation circumference are the main contributors to the electrical connection between the pulmonary veins and the left atrium. Ablation of these regions results in PV isolation in the majority of patients.

Electrical connection between the left atrium and the pulmonary veins: a study to understand the contribution of myocardial fibers along the standard ablation circumference

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein (PV) isolation with circumferential ablation around ipsilateral PVs is the standard strategy for atrial fibrillation ablation. The electrical connection between the left atrium (LA) and the pulmonary veins (PV) is determined by the heterogeneous arrangement of myocardial fibers along the PV-LA junction. Purpose We sought to assess which regions of the standard ablation circumference are the main contributors to the venoatrial electrical connection. Methods Forty-one patients underwent a specific atrial fibrillation ablation protocol in which the anterior and posterior segments of the standard circumference were ablated first. If PV isolation was not achieved, ablation was extended superiorly or inferiorly, based on the earliest atrial activation recorded during pacing from the PV. Complete PV isolation and the length of the areas non-requiring ablation (ANRA) at the time of electrical isolation were evaluated. Results Ablation of the anterior and posterior segments of the standard circumference led to isolation of 77% left-PV pairs and 51% right-PV pairs (p=0,015). A superior extension was required in 23% left-PV pairs and in 46% right-PV pairs, while an inferior extension was required only in 10% left-PV pairs and in 11% right-PV pairs. PV isolation was achieved before completing the standard ablation circumference in 97% left-PV pairs and in 94% right-PV pairs, with an ANRA of 35.8±9.0mm in left PVs (16.1±5.2 mm superior and 19.7±5.6 mm inferior, p&amp;lt;0,01), and 35.5±9.5 mm in right PVs (15.2±5.7 mm superior and 20.9±5.3mm inferior, p&amp;lt;0,01). Conclusion The myocardial fibers along the anterior and posterior regions of the standard ablation circumference are the main contributors to the electrical connection between the LA and the PVs. Ablation of these regions results in PV isolation in the majority of patients.

The spatiotemporal electrogram dispersion ablation targeting rotors is more effective for elderly patients than non-elderly population.

Modulating atrial fibrillation (AF) drivers has been proposed as one of the effective ablation strategies for non-paroxysmal AF (non-PAF). However, the optimal non-PAF ablation strategy is still under debate because the exact mechanisms of AF persistence including focal activity and/or rotational activity, are not well-understood. Recently, spatiotemporal electrogram dispersion (STED) assumed to indicate rotors in the form of rotational activity is proposed as an effective target for non-PAF ablation. We aimed to clarify the effectiveness of STED ablation for modulating AF drivers. STED ablation plus pulmonary vein isolation was applied in 161 consecutive non-PAF patients not undergoing previous ablation. STED areas within the entire left and right atria were identified and ablated during AF. After the procedures, the STED ablation's acute and long-term outcomes were investigated. (1) Despite a more effective acute outcome of the STED ablation for both AF termination and non-inducibility of atrial tachyarrhythmias (ATAs), Kaplan-Meier curves showed that the 24-month freedom ratio from ATAs was 49%, which resulted from the higher recurrence ratio of atrial tachycardia (AT) rather than AF. (2) A multivariate analysis showed that the determinant of ATA recurrences was only a non-elderly age, not long-standing persistent AF, and an enlarged left atrium, which were conventionally considered as key factors. STED ablation targeting rotors was effective in elderly non-PAF patients. Therefore, the main mechanism of AF persistency and the component of the fibrillatory conduction might vary between elders and non-elders. However, we should be careful about post-ablation ATs following substrate modification.

Effect of gender on atrial fibrillation ablation outcomes using a propensity score-matched analysis.

Previous studies have shown that women with atrial fibrillation (AF) have a higher incidence of recurrence and non-pulmonary vein (non-PV) triggers. However, there remains an incomplete understanding of the impact of gender on AF ablation strategies and outcomes. The purpose of this study was to evaluate the impact of gender on AF ablation outcomes. We analyzed 1568 AF ablations in 1412 patients (34% female) performed at a single tertiary care center between January 2013 and July 2021. Patients were followed for at least 6 months (mean 34 months) for detection of AF recurrence, complications, and emergency department visits/hospitalizations. The effect was assessed by multivariate logistic regression analysis using propensity score matching (PSM). Mean age was 64 years, and mean body mass index (BMI) was 31 kg/m2. Seventy-seven percent of patients underwent de novo ablations. Twenty-seven percent of patients had persistent AF, with a recurrence rate of 37%. There was no difference in AF recurrence when stratified by gender (hazard ratio [HR] 1.15; 95% confidence interval [CI] 0.92-1.43; P >.05) and age. After PSM gender 1:1 (criteria: age, type of AF, hypertension, diabetes mellitus, and BMI; n = 888 patients), there was no difference in AF recurrence or procedure-related complications. Having a history of persistent AF (HR 1.54; 95% CI 1.18-1.99; P = .001) predisposed to recurrence of AF. Persistent AF (HR 2.99; 95% CI 1.94-4.78; P <.001) and age >70 years (HR 1.03; 95% CI 1.02-1.05; P <.001) were associated with the need for additional substrate modification with no difference based on gender. There was no difference in overall safety or efficacy outcomes between genders after AF ablation.

AB-452642-1 TEMPORAL TREND IN PROCEDURE-RELATED COMPLICATIONS OF CATHETER ABLATION FOR ATRIAL FIBRILLATION: A SYSTEMATIC REVIEW AND POOLED ANALYSIS OF RANDOMIZED CONTROL TRIALS.

Catheter ablation of atrial fibrillation (AF) is one of the most commonly performed procedures in electrophysiology. However, it is associated with potentially significant complications. Reported procedure-related complication rates are highly variable, depending in part on study design. Objectives of this systematic review and pooled analysis were to determine the rate of procedure-related complications associated with catheter ablation of AF using data from randomized control trials (RCTs), and to assess temporal trends. MEDLINE and EMBASE databases were searched from January 2013 to September 2022 for RCTs that included patients undergoing a first catheter ablation procedure for the treatment of AF using either radiofrequency or cryoballoon ablation (PROSPERO CRD42022370273). The study adhered to Cochrane Collaboration guidelines. The quality of included trials was assessed using the Cochrane Collaboration’s tool for assessing risk of bias in RCTs. Results were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses report. A total of 1,468 references were retrieved and evaluated, of which 89 studies met inclusion criteria. A total of 15,701 patients who underwent a first catheter ablation procedure for AF were included in the current analysis. Procedure-related and severe complication rates were 3.5% (95%CI: 2.9-4.1) and 2.1% (95%CI: 1.7-2.5), respectively. Vascular complications were the most frequent type of complication (1.21%). The most frequently reported complications were then pericardial effusions and tamponades (0.51%), strokes/transient ischemic attacks (0.48%) and reversible phrenic nerve palsy (0.40%). The procedure-related complication rate during the most recent 5-year period of publication [2018-2022] was significantly lower than during the earlier 5-year period [2013-2017] (2.9% vs 4.1%, p=0.043). The pooled mortality rate was stable over the two time periods (0.06% vs 0.05%, p=0.562). By meta-regression analyses, there was no significant difference in complication rate according to pattern of AF (paroxysmal or non-paroxysmal), ablation modality (radiofrequency or cryoballoon), or additional ablation strategies beyond pulmonary vein isolation. Procedure-related complications and mortality rates associated with catheter ablation of AF are low and have declined in the past decade.

PO-02-208 CHARACTERIZATION OF ATRIAL ELECTROPHYSIOLOGICAL PROPERTIES IN PATIENTS WITH HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY

Atrial fibrillation (AF) occurs frequently in patients with hypertrophic obstructive cardiomyopathy (HOCM) and the success rate of pulmonary vein isolation in these patients is less effective compared to other populations. This may be explained by the presence of an extensive arrhythmogenic substrate in both atria due to a primary atrial myopathy, but electrophysiological properties of the right (RA) and left atrium (LA) have never been investigated. The aim of this study is to 1) quantify atrial electrophysiological properties during sinus rhythm and 2) to determine whether atrial electrogram morphology and conduction disorders differ between the RA and LA in patients with HOCM. Intra-operative epicardial mapping of both atria was performed in HOCM patients undergoing surgical myectomy. Conduction delay and/or block (CD, CB), unipolar electrograms characteristics (unipolar voltages, potential fractionation) and low voltage areas (LVA) were quantified during sinus rhythm. Fifteen patients (mean age: 50± 12 years) were included. Conduction disorders were found in both atria in all patients, but did not differ between the RA and LA (CD: 2.9 [1.9-3.6] % versus 2.6 [2.1-6.4] %, p=0.541; CB: 1.7 [0.9-3.1] % versus 1.5 [0.5-2.8] %, p=0.600; respectively). Though unipolar voltages histograms differed significantly between the RA and LA (Table 1), LVA were equally present in both RA and LA (RA: 4.7 % [1.6-7.7] % versus LA: 2.9 % [2.1-7.1] %, p=0.793). The magnitude of unipolar voltages of single- and complex fractionated potentials (SP, CFP) were higher in the LA compared to the RA (SP: P75 10.9 mV versus 7.3 mV, respectively; CFP: P75 3.7 mV versus 2.0 mV, respectively).(Table 1) CFP corresponded to LVA in only 18% of all LA sites compared to 36% of all RA sites. In patients with HOCM, the magnitude of unipolar voltages is considerably higher in the LA compared to the RA. Remarkably, fractionated potentials in both atria mainly contained high voltage deflections. Therefore, substrate modification strategies, consisting of low voltage or other electrogram morphology guided AF ablation strategies, should be disease-tailored in this population. The observed equal amount of conduction disorders and LVA in both atria support the concept of a primary atrial myopathy with a bi-atrial substrate in HOCM patients.

The Impact of Standard Ablation Strategies for Atrial Fibrillation on Cardiovascular Performance in a Four-Chamber Heart Model

PurposeAtrial fibrillation is one of the most frequent cardiac arrhythmias in the industrialized world and ablation therapy is the method of choice for many patients. However, ablation scars alter the electrophysiological activation and the mechanical behavior of the affected atria. Different ablation strategies with the aim to terminate atrial fibrillation and prevent its recurrence exist but their impact on the performance of the heart is often neglected.MethodsIn this work, we present a simulation study analyzing five commonly used ablation scar patterns and their combinations in the left atrium regarding their impact on the pumping function of the heart using an electromechanical whole-heart model. We analyzed how the altered atrial activation and increased stiffness due to the ablation scars affect atrial as well as ventricular contraction and relaxation.ResultsWe found that systolic and diastolic function of the left atrium is impaired by ablation scars and that the reduction of atrial stroke volume of up to 11.43% depends linearly on the amount of inactivated tissue. Consequently, the end-diastolic volume of the left ventricle, and thus stroke volume, was reduced by up to 1.4 and 1.8%, respectively. During ventricular systole, left atrial pressure was increased by up to 20% due to changes in the atrial activation sequence and the stiffening of scar tissue.ConclusionThis study provides biomechanical evidence that atrial ablation has acute effects not only on atrial contraction but also on ventricular performance. Therefore, the position and extent of ablation scars is not only important for the termination of arrhythmias but is also determining long-term pumping efficiency. If confirmed in larger cohorts, these results have the potential to help tailoring ablation strategies towards minimal global cardiovascular impairment.

Different catheter ablation strategies for atrial fibrillation in patients with chronic heart failure

Different catheter ablation strategies for atrial fibrillation in patients with chronic heart failure