Quantitative Investigation of the Acute Lesions Created by an Ethanol Infusion into the Vein of Marshall.

BACKGROUND: Ethanol infusion (EI) into the vein of Marshall (VOM) (EIVOM) has been performed as an adjunctive atrial fibrillation (AF) therapy. However, the time course change, quantitative lesion investigation, and effects on the epicardial fat pads and fractionated atrial electrograms created by the EIVOM have never been investigated. OBJECTIVE: This study aimed to perform a quantitative analysis of lesions created by the EIVOM. METHODS: We created voltage maps using a 3D mapping system immediately, 30 , and 60 minutes after performing the EIVOM to study the time course change in the lesions. Among them, we compared the differences in the average contact force (CF) value, which was required for successful conduction block in the VOM area between patients with and without EIVOM. We also investigated the effects of the EIVOM on the area of continuous fractionated atrial electrograms (CFAE) before and post-EIVOM. We measured the total epicardial fat pad volume before and after the EIVOM using computed tomography. RESULTS: The voltage was significantly reduced after the EIVOM, and there were significant differences regarding the voltage reduction among the control, 30 minutes and 60 minutes after the EIVOM (p<0.05). The average CF value was significantly lower with rather than without an EIVOM (p<0.05). The total epicardial fat volume and CFAE area also significantly decreased after the EIVOM (p<0.05). CONCLUSION: The EIVOM provided significant therapeutic effects on the left atrial tissue perpetuating AF, which was demonstrated by a quantitative analysis.

Long-term Outcome of Cryoballoon Ablation in Korean Patients With Atrial Fibrillation: Real-world Experience From the Cryo Global Registry.

BACKGROUND AND OBJECTIVES: Atrial fibrillation (AF), the most common atrial arrhythmia (AA), is an increasing healthcare burden in Korea. The objective of this sub-analysis of the Cryo Global Registry was to evaluate long-term efficacy, symptom burden, quality of life (QoL), and healthcare utilization outcomes and factors associated with AA recurrence in Korean patients treated with cryoballoon ablation (CBA). METHODS: Patients were treated and followed up according to local standard-of-care in 3 Korean hospitals. Kaplan-Meier estimates were used in analyzing (1) efficacy defined as freedom from ≥30 second recurrence of AA at 24 months, (2) healthcare utilization, and (3) predictors of 24-month AA recurrence. Patient-reported QoL (using European Quality of Life-5 Dimensions-3 Levels) and predefined AF-related symptoms were assessed at baseline and 24-month follow-up. RESULTS: Efficacy was 71.9% in paroxysmal AF (PAF) and 49.3% in persistent AF (PsAF) patients (p<0.01). A larger left atrial diameter (LAD), an increased time from AF diagnosis to CBA, and PsAF were independent predictors of AA recurrence. The percentage of patients with no AF symptoms significantly increased from baseline (24.5%) to 24-month (89.5%) follow-up (p<0.01). Improvement in QoL from baseline to 24 months was not statistically different between AF cohorts. PAF patients experienced greater freedom from repeat ablations (93.9% vs. 81.4%) and cardiovascular hospitalizations (91.3% vs. 72.5%, p<0.001 for both). CONCLUSIONS: In alignment with global outcomes, CBA is an effective treatment for AF in the Korean population, with patients possessing a large LAD and not receiving ablation soon after diagnosis being the most at risk for AA recurrence. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02752737.

QT Prolongation and Torsade De Pointes After Catheter Ablation for Persistent Atrial Fibrillation in a Patient With Tachycardia-Induced Cardiomyopathy: A Case Report.

Atrial fibrillation (AF) is the most common cause of tachycardia-induced cardiomyopathy (TIC). A 75-year-old woman was referred to our hospital for catheter ablation for persistent AF. On admission, transthoracic echocardiography (TTE) revealed diffuse left ventricular (LV) hypokinesis, which was suspected to be due to TIC. Catheter ablation was performed on the fifth day of hospitalization, and Torsade de Pointes (TdP) appeared on the sixth day. The serum concentration of bepridil and potassium was below the reference level. An electrocardiogram revealed marked QT prolongation, giant-negative T waves, and T-wave alternans on the seventh day of hospitalization. Cardiac magnetic resonance imaging with no contrast indicated diffuse mild LV hypokinesis, mild prolonged native T1, and no evidence of myocardial edema at T2. Coronary angiography revealed normal coronary arteries, and the ergonovine stress test results were negative. The results for five long QT syndrome susceptibility genes, including the three major genes, were negative. Subsequently, QT prolongation, giant-negative T waves, and LV dysfunction improved without treatment. This case report highlights the importance of risk management for AF patients with TIC scheduled for catheter ablation and carefully evaluating the risks of QT prolongation. Moreover, patients with TIC can experience marked QT prolongation and TdP during the perioperative period of catheter ablation. Therefore, caution should be required.

ST-segment depression and left ventricular systolic function recovery post-atrial fibrillation ablation in heart failure.

AIMS: Catheter ablation (CA) of atrial fibrillation (AF) improves left ventricular ejection fraction (LVEF) in patients with heart failure with reduced ejection fraction (HFrEF). The impact of ST-segment depression before CA on LVEF recovery and clinical outcomes remains unknown. In the present study, we aimed to investigate the relationship between ST-segment depression during AF rhythm before CA and improvement in the LVEF and clinical outcomes in persistent atrial fibrillation (PerAF) patients with HFrEF. METHODS AND RESULTS: The present study included 122 PerAF patients (male; 98 patients, 80%, mean age: 69 [56, 76] years) from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry who had LVEF < 50% and underwent an initial ablation. The patients who underwent percutaneous coronary intervention or coronary artery bypass grafting within the past 1 month were not included in the enrolled patients. We assigned the patients based on the presence of ST-segment depression before CA during AF rhythm and evaluated improvement in the LVEF (LVEF ≥ 15%) 1 year after CA and the relationship between ST-segment depression and heart failure (HF) hospitalization/major adverse cardiovascular events (MACE), which are defined as a composite of HF hospitalization, cardiovascular death, hospitalization due to coronary artery disease, ventricular arrhythmia requiring hospitalization and stroke. The percentage of patients with improvement in the LVEF 1 year after CA was significantly lower in the patients with ST-segment depression than those without (58.6% vs. 79.7%, P = 0.012). Multiple regression analysis showed ST-segment depression was independently and significantly associated with improvement in the LVEF 1 year after CA (HR: 0.35; 95% CI: 0.129-0.928, P = 0.035). Kaplan-Meier analysis showed that the patients with ST-segment depression significantly had higher risk of HF hospitalization and MACE than those without (log rank P = 0.022 and log rank P = 0.002, respectively). Multivariable Cox proportional hazards analysis showed that ST-segment depression was independently and significantly associated with a higher risk of MACE (HR: 2.82; 95% CI: 1.210-6.584, P = 0.016). CONCLUSIONS: ST-segment depression before CA during AF rhythm was useful prognostic predictor of improvement in the LVEF and clinical outcomes including HF hospitalization and MACE in PerAF patients with HFrEF.

A novel approach to terminate roof-dependent atrial flutter with epicardial conduction through septopulmonary bundle.

Atrial flutter, a prevalent cardiac arrhythmia, is primarily characterized by reentrant circuits in the right atrium. However, atypical forms of atrial flutter present distinct challenges in terms of diagnosis and treatment. In this study, we examine three noteworthy clinical cases of atypical atrial flutter, which offer compelling evidence indicating the implication of the lesser-known Septopulmonary Bundle (SPB). This inference is based on the identification of distinct electrocardiographic patterns observed in these patients and their favorable response to catheter ablation, which is a standard treatment for atrial flutter. Remarkably, in each case, targeted ablation at the anterior portion of the left atrial roof effectively terminated the arrhythmia, thus providing further support for the hypothesis of SPB involvement. These insightful observations shed light on the potential significance of the SPB in the etiology of atypical atrial flutter and introduce a promising therapeutic target. We anticipate that this paper will stimulate further exploration into the role of the SPB in atrial flutter and pave the way for the development of targeted ablation strategies.

Advances and Challenges in the Management of Brugada Syndrome: A Comprehensive Review.

Brugada syndrome (BrS) is an inherited arrhythmogenic disorder marked by distinctive ST-segment elevations on electrocardiograms (ECG) and an increased risk of sudden cardiac death. Characterized by mutations primarily in the SCN5A gene, BrS disrupts cardiac ion channel function, leading to abnormal electrical activity and arrhythmias. Although BrS primarily affects young, healthy males, it poses significant diagnostic challenges due to its often concealed or intermittent ECG manifestations and clinical presentation that can mimic other cardiac disorders. Current management strategies focus on symptom control and prevention of sudden death, with implantable cardioverter-defibrillators (ICD) serving as the primary intervention for high-risk patients. However, the complications associated with ICDs and the lack of effective pharmacological options necessitate a cautious and personalized approach. Recent advancements in catheter ablation have shown promise, particularly for managing ventricular fibrillation (VF) storms and reducing ICD shocks. Additionally, pharmacological treatments such as quinidine have been effective in specific cases, though their use is limited by availability and side effects. This review highlights significant gaps in the BrS literature, particularly in terms of long-term management and novel therapeutic approaches. The importance of genetic screening and tailored treatment strategies to better identify and manage at-risk individuals is emphasized. The review aims to enhance the understanding of BrS and improve patient outcomes, advocating for a multidisciplinary approach to this complex syndrome.

Catheter ablation for focal atrial tachycardias during pregnancy: A systematic review.

OBJECTIVE: Pregnancy can trigger maternal tachycardias, and the onset of recurrent or incessant focal atrial tachycardia (AT) can lead to tachycardia-induced cardiomyopathy. Medical interventions are commonly employed, but they carry potential fetal and maternal risks. Catheter ablation (CA), particularly with non-fluoroscopic navigation systems, may be considered as an alternative. This systematic review aims to explore the feasibility and outcomes of CA for focal AT during pregnancy. METHODS: A thorough literature search was conducted until September 30th, 2023, on PubMed, Embase, and Cochrane databases. Included articles described maternal focal ATs diagnosed through electrophysiological studies and treated with CA. Data derived from these studies were organized into tables and subsequently analyzed. RESULTS: Out of 278 papers reviewed, 15 articles involving 24 patients were retrieved. CA, utilizing radiofrequency energy achieved acute success in 95.8% of cases. Sixteen patients (66.7%) underwent complete fluoroless procedures, with two adverse events directly related to the procedure reported. Long-term follow-up revealed minimal AT recurrences, with a 0.06% arrhythmia burden in one case. CONCLUSION: Focal ATs during pregnancy can be incessant and refractory to medical intervention, precipitating an acute decline in left ventricular ejection fraction. In this setting, CA emerges as an efficacious treatment modality, particularly in cases of tachycardia-induced cardiomyopathies. Whenever feasible, it is advisable to perform these procedures with minimal or no fluoroscopy guidance. Larger studies are needed to establish the safety and the efficacy of CA for focal ATs during pregnancy, as current research consists of case reports or small case series.

Contact-force local impedance algorithm to guide effective pulmonary vein isolation in AF patients: 1-year outcome from an international multicenter clinical setting.

BACKGROUND: The combination of highly localized impedance (LI) and contact force (CF) may improve tissue characterization and lesion prediction during radiofrequency (RF) pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). OBJECTIVE: We report the outcomes of our acute and long-term clinical evaluation of CF-LI-guided PVI in consecutive AF ablation cases from an international multicenter clinical setting. METHODS: Three hundred twenty-four consecutive patients from 20 European centers undergoing RF catheter ablation with the Stablepoint™ catheter were enrolled in the CHARISMA registry. Of these, 275 had a minimum follow-up of 1 year and were included in the primary analysis. RESULTS: The mean procedure duration was 115 ± 47 min, and the mean fluoroscopy time was 9.9 ± 6 min. At the end of the procedures, all PVs had been successfully isolated in all study patients. Minor complications were reported in 12 patients (4.4%). At 1 year, 36 (13.1%) patients had had an AF recurrence, and freedom from antiarrhythmic drugs and AF recurrence was achieved in 228 (82.9%) patients. The recurrence rate was higher in patients with persistent AF (21/116, 18.1%) than in those with paroxysmal AF (15/159, 9.4%; p = 0.0459). On multivariate logistic analysis adjusted for baseline confounders, only time > 6 months from first diagnosis of AF to ablation (HR = 2.93, 95%CI 1.03 to 8.36, p = 0.0459) was independently associated with recurrences. CONCLUSION: An ablation strategy for PVI guided by CF-LI technology proved safe and effective and resulted in a low recurrence rate of AF over 1-year follow-up, irrespective of the underlying AF type. CLINICAL TRIAL REGISTRATION: Catheter Ablation of Arrhythmias with a High-Density Mapping System in Real-World Practice. (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998.

Benefits from catheter ablation in patients with pulmonary hypertension: Recent advances.

Supraventricular tachycardia (SVT) is a frequent complication of pulmonary hypertension (PH). The most prevalent SVTs are atrial fibrillation (AF) and typical atrial flutter (AFL), followed by focal and macroreentrant atrial tachycardia (AT) and nodal arrhythmia (AV nodal reentry tachycardia or AV reentry tachycardia). SVT is frequently associated with functional deterioration and right ventricular failure in PH patients. According to some data, reestablishing sinus rhythm is associated with clinical improvement. Catheter ablation of typical AFL, nodal tachyarrhythmias, or other less complex focal ATs have been shown to be feasible, acutely effective, and safe in patients with PH. However, the long-term clinical outcome is modified by the recurrence of index arrhythmia and the onset of a new SVT. Due to right atrial dilatation, technical issues can arise when ablation is carried out. The role of catheter ablation in patients with AF or more complex AT is even less effective. The results mirror the success rate in the general AF population with non-paroxysmal AF. However, the data is limited, and electrophysiological procedures are also more often complicated by specific adverse events in a severely frail population. Despite these limitations, catheter ablation is the treatment of choice in less complex SVT, but the indications for AF ablation must be more individualized.

Oesophago-pericardial fistula after catheter ablation of atrial fibrillation: a case report.

Background: Oesophageal fistula is a rare complication of catheter ablation of atrial fibrillation with most fistulas being atrio-oesophageal fistulas, but oesophageal-pericardial fistula can also happen in the absence of atrial perforation. Case summary: A 68-year-old male patient presented with chest pain 10 days after catheter ablation of paroxysmal atrial fibrillation. He was discharged after an initial negative workup that included a CT chest without contrast. He later presented again with severe chest pain and fever and was found to have an oesophageal-pericardial fistula. He underwent surgical and endoscopic treatment with good recovery. Discussion: Patients with oesophago-pericardial fistulas often have delayed presentation 1-4 weeks after the ablation procedure. Early diagnosis can be challenging. CT with oral and intravenous contrast is often used for diagnosis. Treatment often includes antibiotics, surgical or interventional drainage of infected spaces with oesophageal repair, clipping or stenting. In contrast to atrio-oesophageal fistulas that carry a high mortality rate, mortality for oesophago-pericardial fistulas appears to be much lower.

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Objective: Atrial fibrillation (AF) is a disease of high heterogeneity, and the association between AF phenotypes and the outcome of different catheter ablation strategies remains unclear. Conventional classification of AF (e.g. according to duration, atrial size, and thromboembolism risk) fails to provide reference for the optimal stratification of the prognostic risks or to guide individualized treatment plan. In recent years, research on machine learning has found that cluster analysis, an unsupervised data-driven approach, can uncover the intrinsic structure of data and identify clusters of patients with pathophysiological similarity. It has been demonstrated that cluster analysis helps improve the characterization of AF phenotypes and provide valuable prognostic information. In our cohort of AF inpatients undergoing radiofrequency catheter ablation, we used unsupervised cluster analysis to identify patient subgroups, to compare them with previous studies, and to evaluate their association with different suitable ablation patterns and outcomes. Methods: The participants were AF patients undergoing radiofrequency catheter ablation at West China Hospital between October 2015 and December 2017. All participants were aged 18 years or older. They underwent radiofrequency catheter ablation during their hospitalization. They completed the follow-up process under explicit informed consent. Patients with AF of a reversible cause, severe mitral stenosis or prosthetic heart valve, congenital heart disease, new-onset acute coronary syndrome within three months prior to the surgery, or a life expectancy less than 12 months were excluded according to the exclusion criteria. The cohort consisted of 1102 participants with paroxysmal or persistent/long-standing persistent AF. Data on 59 variables representing demographics, AF type, comorbidities, therapeutic history, vital signs, electrocardiographic and echocardiographic findings, and laboratory findings were collected. Overall, data for the variables were rarely missing (<5%), and multiple imputation was used for correction of missing data. Follow-up surveys were conducted through outpatient clinic visits or by telephone. Patients were scheduled for follow-up with 12-lead resting electrocardiography and 24-hours Holter monitoring at 3 months and 6 months after the ablation procedure. Early ablation success was defined as the absence of documented AF, atrial flutter, or atrial tachycardia >30 seconds at 6-month follow-up. Hierarchical clustering was performed on the 59 baseline variables. All characteristic variables were standardized to have a mean of zero and a standard deviation of one. Initially, each patient was regarded as a separate cluster, and the distance between these clusters was calculated. Then, the Ward minimum variance method of clustering was used to merge the pair of clusters with the minimum total variance. This process continued until all patients formed one whole cluster. The "NbClust" package in R software, capable of calculating various statistical indices, including pseudo t2 index, cubic clustering criterion, silhouette index etc, was applied to determine the optimal number of clusters. The most frequently chosen number of clusters by these indices was selected. A heatmap was generated to illustrate the clinical features of clusters, while a tree diagram was used to depict the clustering process and the heterogeneity among clusters. Ablation strategies were compared within each cluster regarding ablation efficacy. Results: Five statistically driven clusters were identified: 1) the younger age cluster (n=404), characterized by the lowest prevalence of cardiovascular and cerebrovascular comorbidities but the highest prevalence of obstructive sleep apnea syndrome (14.4%); 2) a cluster of elderly adults with chronic diseases (n=438), the largest cluster, showing relatively higher rates of hypertension, diabetes, stroke, and chronic obstructive pulmonary disease; 3) a cluster with high prevalence of sinus node dysfunction (n=160), with patients showing the highest prevalence of sick sinus syndrome and pacemaker implantation; 4) the heart failure cluster (n=80), with the highest prevalence of heart failure (58.8%) and persistent/long-standing persistent AF (73.7%); 5) prior coronary artery revascularization cluster (n=20), with patients of the most advanced age (median: 69.0 years old) and predominantly male patients, all of whom had prior myocardial infarction and coronary artery revascularization. Patients in cluster 2 achieved higher early ablation success with pulmonary veins isolation alone compared to extensive ablation strategies (79.6% vs. 66.5%; odds ratio [OR]=1.97, 95% confidence interval [CI]: 1.28-3.03). Although extensive ablation strategies had a slightly higher success rate in the heart failure group, the difference was not statistically significant. Conclusions: This study provided a unique classification of AF patients undergoing catheter ablation by cluster analysis. Age, chronic disease, sinus node dysfunction, heart failure and history of coronary artery revascularization contributed to the formation of the five clinically relevant subtypes. These subtypes showed differences in ablation success rates, highlighting the potential of cluster analysis in guiding individualized risk stratification and treatment decisions for AF patients.

Association of Paroxysmal Versus Persistent Atrial Fibrillation with In-hospital Outcomes and 30-day Readmission After Inpatient Atrial Fibrillation Ablation.

Knowledge of the impact of paroxysmal and persistent atrial fibrillation (AF) after catheter ablation on in-hospital outcomes and 30-day readmission remains limited. This study aimed to evaluate the procedural outcomes and 30-day readmission rates among patients with paroxysmal or persistent AF who were hospitalized for AF ablation. Using the Nationwide Readmissions Database, our study included patients aged ≥18 years with AF who were hospitalized and underwent catheter ablation during 2017-2020. Then, we compared the in-hospital procedural outcomes and 30-day readmission rates between patients with paroxysmal and persistent AF, respectively. Our study included 7310 index admissions for paroxysmal AF ablation and 9179 index admissions for persistent AF ablation. According to our analysis, there was no significant difference in procedural complications-namely, cerebrovascular accident, vascular complications, major bleeding requiring blood transfusion, phrenic nerve palsy, pericardial complications, and systemic embolization-between the persistent and paroxysmal AF groups. There was also no significant difference in early mortality between these groups (0.5% vs. 0.7%; P = .22). Persistent AF patients had significantly higher rates of prolonged index hospitalization (9.9% vs. 7.2%; P < .01) and non-home discharge (4.8% vs. 3.1%; P < .01). The 30-day readmission rates were comparable in both groups (10.0% vs. 9.5%; P = .34), with recurrent AF and heart failure being two of the most common causes of cardiac-related readmissions. Catheter ablation among hospitalized patients with paroxysmal or persistent AF resulted in no significant difference in procedural complications, early mortality, or 30-day readmission. This suggests that catheter ablation of AF can be performed with a relatively similar safety profile for both paroxysmal and persistent AF.

Antiarrhythmic drug therapy and catheter ablation in patients with paroxysmal or persistent atrial fibrillation: a systematic review and meta-analysis.

BACKGROUND: Catheter ablation and antiarrhythmic drug therapy are utilized for rhythm control in atrial fibrillation (AF), but their comparative effectiveness, especially with contemporary treatment modalities, remains undefined. We conducted a systematic review and meta-analysis contrasting current ablation techniques against antiarrhythmic medications for AF. METHODS: We searched PubMed, SCOPUS, Cochrane CENTRAL, and Web of Science until November 2023 for randomized trials comparing AF catheter ablation with antiarrhythmics, against antiarrhythmic drug therapy alone, reporting outcomes for > 6 months. Four investigators extracted data and appraised risk of bias (ROB) with ROB 2 tool. Meta-analyses estimated pooled efficacy and safety outcomes using R software. RESULTS: Twelve trials (n = 3977) met the inclusion criteria. Catheter ablation was associated with lower AF recurrence (relative risk (RR) = 0.44, 95%CI (0.33, 0.59), P ˂ 0.0001) and hospitalizations (RR = 0.44, 95%CI (0.23, 0.82), P = 0.009) than antiarrhythmic medications. Catheter ablation also improved the physical quality of life component score (assessed by a 36-item Short Form survey) by 7.61 points (95%CI -0.70-15.92, P = 0.07); but, due to high heterogeneity, it was not statistically significant. Ablation was significantly associated with higher procedural-related complications [RR = 15.70, 95%CI (4.53, 54.38), P < 0.0001] and cardiac tamponade [RR = 9.22, 95%CI (2.16, 39.40), P = 0.0027]. All-cause mortality was similar between the two groups. CONCLUSIONS: For symptomatic AF, upfront catheter ablation reduces arrhythmia and hospitalizations better than continued medical therapy alone, albeit with moderately more adverse events. Careful patient selection and risk-benefit assessment are warranted regarding the timing of ablation.

Incidence and predictors of persistent iatrogenic atrial septal defect following catheter ablation.

BACKGROUND: The left atrium approach for atrial fibrillation (AF) ablation requires an atrial transseptal puncture that may cause an iatrogenic atrial septal defect (iASD). This study aimed to investigate the incidence and predictors of iASD in catheter ablation, assessed by transthoracic echocardiography (TTE), a relatively non-invasive technique frequently employed in follow-up. METHODS: This retrospective study included 639 patients (489 male; 60.2 ±â€¯10.7 years) who underwent initial catheter ablation for AF between May 2005 and June 2018. All patients underwent preprocedural transesophageal echocardiography (pre-TEE), preprocedural TTE (pre-TTE), and TTE one day after the procedure (post-TTE). iASD incidence after 6 months (6 M), preprocedural characteristics, and procedure methods were evaluated. RESULTS: Patent foramen ovale (PFO) was diagnosed in 42 patients (6.6 %) using pre-TEE and in 11 patients using pre-TTE (26.2 % of the patients with PFO in pre-TEE). Among the 597 patients without PFO, 497 underwent 6 M-TTE. iASD was observed in 59.6 % of patients using post-TTE and 4.6 % using 6 M-TTE. In the univariate logistic regression analysis, the total diameter of the sheath through the septum (odds ratio 1.15, p < 0.001) or two sheaths through a single puncture (odds ratio 4.17, p = 0.001) were independent risk factors on iASD incidence in 6 M-TTE. iASD was also more likely to occur via cryoballoon ablation using a larger sheath than radiofrequency catheter ablation. CONCLUSIONS: iASD was not a rare complication. A larger sheath diameter or two sheaths through a single puncture were associated with the incidence of iASD.

Potential microemboli formation risk and its management during the heated saline-enhanced radiofrequency needle-tip catheter ablation.

BACKGROUND: The potential risk of embolic events during ablation in the left ventricle (LV) with a heated saline-enhanced radiofrequency (SERF) needle-tip ablation catheter has not been characterized. OBJECTIVE: This study aimed to investigate the formation of microemboli or other untoward events during SERF ablation. METHODS: Ninety-three radiofrequency (RF) ablation procedures were performed in the LV of 14 pigs by using a SERF catheter (35 W, 70 seconds, and 60°C; normal or degassed saline [NS or DS] irrigation with a flow rate of 10 mL/min) vs a standard irrigated-tip radiofrequency (S-RF) catheter (30 or 50 W, 30 seconds, and 17 mL/min). Microbubble formation was graded on the basis of intracardiac echocardiography. Microbubbles, microembolic signals, and microparticles were monitored using our established model. RESULTS: There was no significant difference in microbubble volume among SERF-NS, SERF-DS, and S-RF 30 W with "grade 1" intracardiac echocardiography microbubbles (median and 25th-75th percentiles 0.201 [0.011-3.13], 0.455 [0.06-2.66], and 0.004 µL [0.00-0.16 µL], respectively). There was no significant difference in microembolic signals among SERF-NS, SERF-DS, and S-RF 30 W with grade 1 bubbles (n = 8.0 ± 5.8, n = 7.6 ± 4.2, and n = 6.1 ± 6.1, respectively). Both SERF-NS and SERF-DS created larger lesions than did both S-RF 30 W and S-RF 50 W deliveries (mean 1241.5 ± 658.6, 1497.7 ± 893.4, 75.0 ± 24.8, and 184.0 ± 93.8 mm3; P < .001). There was no significant difference in microparticle incidence among groups (P = .675). No evidence of embolic events was found in the brain and other organs at the histology assessment. CONCLUSION: In the setting of SERF ablation, significantly large LV lesions can be created without any increment in embolic microbubble or particle events. Grade 1 microbubble is related to the efficacy and safety.

Efficacy and safety of a novel hexaspline pulsed field ablation system in patients with paroxysmal atrial fibrillation: the PLEASE-AF study.

AIMS: Pulsed field ablation (PFA) is an emerging non-thermal ablative modality demonstrating considerable promise for catheter ablation of atrial fibrillation (AF). However, these PFA trials have almost universally included only Caucasian populations, with little data on its effect on other races/ethnicities. The PLEASE-AF trial sought to study the 12-month efficacy and the safety of a multi-electrode hexaspline PFA catheter in treating a predominantly Asian/Chinese population of patients with drug-refractory paroxysmal AF. METHODS AND RESULTS: Patients underwent pulmonary vein (PV) isolation (PVI) by delivering different pulse intensities at the PV ostium (1800 V) and atrium (2000 V). Acute success was defined as no PV potentials and entrance/exit conduction block of all PVs after a 20-min waiting period. Follow-up at 3, 6, and 12 months included 12-lead electrocardiogram and 24-h Holter examinations. The primary efficacy endpoint was 12-month freedom from any atrial arrhythmias lasting at least 30 s. The cohort included 143 patients from 12 hospitals treated by 28 operators: age 60.2 ± 10.0 years, 65.7% male, Asian/Chinese 100%, and left atrial diameter 36.6 ± 4.9 mm. All PVs (565/565, 100%) were successfully isolated. The total procedure, catheter dwell, total PFA application, and total fluoroscopy times were 123.5 ± 38.8 min, 63.0 ± 30.7 min, 169.7 ± 34.6 s, and 27.3 ± 10.1 min, respectively. The primary endpoint was observed in 124 of 143 patients (86.7%). One patient (0.7%) developed a small pericardial effusion 1-month post-procedure, not requiring intervention. CONCLUSION: The novel hexaspline PFA catheter demonstrated universal acute PVI with an excellent safety profile and promising 12-month freedom from recurrent atrial arrhythmias in an Asian/Chinese population with paroxysmal AF. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05114954.