Drug-resistant Atrial Fibrillation Research Articles

Comparing pulsed field electroporation and radiofrequency ablation for the treatment of paroxysmal atrial fibrillation: design and rationale of the BEAT PAROX-AF randomized clinical trial.

Using thermal-based energy sources [radiofrequency (RF) energy/cryo energy] for catheter ablation is considered effective and safe when performing pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). However, treatment success remains limited and complications can occur due to the propagation of thermal energy into non-target tissues. We aim to compare pulsed field ablation (PFA) with RF ablation in terms of efficacy and safety for patients with drug-resistant paroxysmal AF. The BEAT PAROX-AF trial is a European multicentre, superiority, open-label randomized clinical trial in two parallel groups. A total of 292 participants were recruited in 9 high-volume European clinical centres in 5 countries. Patients with paroxysmal AF were randomized to PFA (FARAPULSE Endocardial Ablation System©, Boston Scientific) or RF using the CLOSE protocol with contact force sensing catheter (SmartTouch© catheter and CARTO© Biosense Webster). The primary endpoint will be the 1-year recurrence of atrial arrhythmia, and the major secondary safety endpoint will be the occurrence of acute (<7 days) procedure-related serious adverse events, or pulmonary vein stenosis, or atrio-oesophageal fistula up to 12 months. Additionally, five sub-studies investigate the effect of PFA on oesophageal safety, cerebral lesions, cardiac autonomic nervous system, durability of PVI as assessed during redo ablation procedures, and atrial and ventricular function. The study began on 27 December 2021 and concluded recruitment on 17 January 2024. Results will be available in mid-2025. The BEAT PAROX-AF trial aims to provide critical insights into the optimal treatment approach for patients with paroxysmal AF.

Impact of Catheter Ablation on Arrhythmia Burden in Patients With Shock-Resistant Persistent Atrial Fibrillation

BackgroundPersistent shock-resistant atrial fibrillation (AF) is a challenging entity, with modest results from catheter ablation according to conventional survival analysis. ObjectivesThe aim of this study was to determine the effect of catheter ablation on atrial tachyarrhythmia (ATA) burden in persistent AF patients undergoing first-time ablation with the use of an implantable cardiac monitor (ICM). MethodsPatients with drug-resistant ongoing persistent AF and at least 1 previous failed cardioversion were implanted with an ICM 2 months before the procedure. All patients underwent pulmonary vein isolation with or without additional substrate ablation depending on the presence of self-terminating AF on ICM and left atrium size. Median AF burden before and after ablation, off antiarrhythmic medication, was determined from ICM recordings after review by 2 independent investigators. ResultsSixty patients were recruited (mean age 66 ± 9 years, 70% male). Mean left atrial diameter was 48 ± 6 mm and median CHA2DS2VASc score was 2. Ten patients (17%) unexpectedly demonstrated self-terminating AF before ablation. The median burden of ATA before ablation was 100% (95% CI: 19.6%-100%), decreasing to 0% (95% CI: 0%-95.8%) after ablation during the post-blanking follow-up period (median reduction 100%; 95% CI: 4%-100%; P < 0.001). Twenty-seven patients (45%) experienced recurrent ATA during 12-month follow-up. In these patients, median burden before ablation was 100% (95% CI: 26.9%-100%), decreasing to 11.4% (95% CI: 0.35%-99.7%) after ablation (P < 0.001). Quality of life improved significantly from baseline, driven by lack of recurrence. ConclusionsPatient-tailored catheter ablation results in a significant reduction in ATA burden (off antiarrhythmic medication) in shock-resistant persistent AF patients using ICMs implanted 2-months pre-procedure. These data suggest that conventional arrhythmia-free survival analysis does not capture the true impact of catheter ablation in this challenging cohort.

Usefulness of the systemic immune inflammation index to predict atrial fibrillation recurrence after cryoablation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter-based atrial fibrillation (AF) ablation is an effective and reliable therapy in the treatment of patients with symptomatic and drug-refractory atrial fibrillation [1, 2]. Several factors and noninvasive clinical markers have been investigated to predict the success rate of catheter ablation[3, 4]. Inflammation is a well-established risk factor in the pathogenesis, initiation and perputuation of AF and in the recurrence of AF following ablation procedures [ 5]. The systemic immune inflammation index (SII) has emerged as a new predictor of inflammation and is determined using the following equation: neutrophil (N) × platelet (P) ÷ lymphocyte (L)[6]. The predictive value of this index on routine blood tests have been examined and suggested to be a powerful and independent prognostic factor of several cardiovascular diseases. [7, 8]. The current study sought to assess whether there is a relationship between SII level and recurrence of AF after catheter ablation. Methods This study was a single center and non-randomized study conducted at our city hospital Department of Cardiology. From January 2019 to March 2021 a total of 370 consecutive patients with symptomatic AF who underwent cryoablation were enrolled. The study population consisted of patients (mean age 56.1±12.3 years, 50.5% male) with drug-resistant symptomatic AF who underwent initial PV isolation with cryoballoon technique for documented AF. The patients were divided into two groups according to receurrence development Results After a mean follow-up period of 25.0±6.7 months, early recurrence was developed in 36 (9.7%) patients and recurrence after blanking period was observed in 77 patients (20.8%) patients. According to multivariate Cox proportional hazard regression analysis, pre-ablation SII level (HR: 2.32, 95% CI: 1.35–3.98, P: 0.002), left ventricular ejection fraction (HR: 0.96, 95% CI: 0.93–0.99, P : 0.020) and EHRA Score (HR: 2.04, 95% CI: 1.34–3.10, P : 0.001) were independent predictors of AF recurrence after cryoablation. In ROC curve analysis, using a cut-off level of 532, the pre-ablation SII level predicted AF recurrence with a sensitivity of 71.4% and a specificity of 67.9% (AUC: 0.88, 95% CI: 0.67–0.80; P &amp;lt;0.001) (Figure 1). In addition, correlation analysis revealed that there was a positive correlation of pre-procedural SII level with pre-procedural hsCRP level (r: 0.340, P &amp;lt;0.001). Figure 2 represent the Kaplan–Meier curves for the freedom from AF recurrence according to SII cut-off level of 532 (log-rank, P &amp;lt; 0.001). Conclusions Our findings revealed that, in patients with paroxysmal and/or persistent AF undergoing cryoablation, increased pre-ablation SII levels were associated with a higher rate of AF recurrence. As a readily available, low-cost and easy to access marker of inflammation, pre-ablation SII level has well-predicted AF recurrence after cryoballoon-based ablation.

P100 RENAL DENERVATION FOR ATRIAL FIBRILLATION IN DRUG–RESISTANT HYPERTENSIVE PATIENTS. AN UPDATED META–ANALYSIS OF RANDOMIZED CONTROLLED TRIALS

Abstract Introduction This meta–analysis of randomized controlled trials (RCT) was permormed to compare clinical outcomes following renal denervation (RDN) in drug–resistant hypertensive patients with atrial fibrillation (AF). Methods Data collection We applied the methods recommended by the Preferred Reporting Items for Systematic Reviews and Meta–Analyses (PRISMA) statement. We searched Pubmed, and the Cochrane Central Register for randomized controlled trials (RCT) that evaluated AF catheter ablation associated with RDN compared with AF catheter ablation alone, in drug–resistant hypertensive patients. Outcome: The primary outcomes was the rate of AF recurrence throughout the follow–up period. Statistical Analysis: The analyses were performed using RevMan version 5.3. The results are presented as odds ratios (OR) for dichotomous outcomes (Inverse variance method, random effect model) with 95% confidence interval (CI). Results Five full texts met inclusion criteria. A total of 531 patients were included (269 patients randomized to catheter ablation and RDN and 262 patients randomized to catheter ablation alone), with a mean follow–up of 16.8 months. We found a significantly lower number of patients with AF recurrence in the AF catheter ablation with RDN group (83/269), respect to AF catheter ablation alone (125/262) at the end of the follow–up (OR 0.51 (0.35–0.72) p 0.0002) RDN procedure in these trials was was safe with an overall compilcation rate of 6.32% Conclusions Combined AF catheter ablation and RDN is beneficial for patients with drug resistant hypertension and AF reducing the risk of AF recurrence.

Successful ablation of atrial fibrillation in a patient with a highly calcified septum after an atrial septal defect operation.

Successful ablation of atrial fibrillation in a patient with a highly calcified septum after an atrial septal defect operation.

Human in vitro assay for irreversible electroporation cardiac ablation.

Introduction: Pulsed electric field (PEF) cardiac ablation has been recently proposed as a technique to treat drug resistant atrial fibrillation by inducing cell death through irreversible electroporation (IRE). Improper PEF dosing can result in thermal damage or reversible electroporation. The lack of comprehensive and systematic studies to select PEF parameters for safe and effective IRE cardiac treatments hinders device development and regulatory decision-making. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been proposed as an alternative to animal models in the evaluation of cardiac electrophysiology safety. Methods: We developed a novel high-throughput in vitro assay to quantify the electric field threshold (EFT) for electroporation (acute effect) and cell death (long-term effect) in hiPSC-CMs. Monolayers of hiPSC-CMs were cultured in high-throughput format and exposed to clinically relevant biphasic PEF treatments. Electroporation and cell death areas were identified using fluorescent probes and confocal microscopy; electroporation and cell death EFTs were quantified by comparison of fluorescent images with electric field numerical simulations. Results: Study results confirmed that PEF induces electroporation and cell death in hiPSC-CMs, dependent on the number of pulses and the amplitude, duration, and repetition frequency. In addition, PEF-induced temperature increase, absorbed dose, and total treatment time for each PEF parameter combination are reported. Discussion: Upon verification of the translatability of the in vitro results presented here to in vivo models, this novel hiPSC-CM-based assay could be used as an alternative to animal or human studies and can assist in early nonclinical device development, as well as inform regulatory decision-making for cardiac ablation medical devices.

An Effective Novel Index for Predicting the Recurrence of Atrial Fibrillation Ablation: P Wave Duration-to-Amplitude Ratio.

Atrial fibrillation is the most common arrhythmia observed in the clinical practice. Pulmonary vein isolation is a well established treatment option for atrial fibrillation but is limited by recurrence. Previous studies have demonstrated that abnormal P wave indices were associated with adverse atrial remodeling and its role in predicting atrial fibrillation recurrence. In the present study, we aimed to evaluate the place of a novel index as we named P wave duration-to-amplitude ratio in predicting the recurrence of atrial fibrillation. Patients who underwent pulmonary vein isolation for symptomatic drug-resistant atrial fibrillation between January 2016 and March 2018 were retrospectively screened. A total of 111 patients were enrolled in the current study. P wave indices of the patients were calculated by precisely measuring the electrocardiogram traces recorded with an electrophysiology recording system. While P wave duration (129 ± 18.4 vs. 109 ± 15.7 ms, P &lt;.001), P wave duration-toamplitude ratio (1072.7 ± 528.3 vs. 626.9 ± 368 ms/mV, P &lt;.001), P wave peak time (65 ± 12 vs. 54 ± 10 ms, P &lt;.001), and P wave dispersion (49 ± 14.1 vs. 27.9 ± 17 ms, P =.001) values were significantly higher in the atrial fibrillation recurrence (+) group, the P wave amplitude (0.12 ± 0.05 vs. 0.18 ± 0.02 mV, P &lt;.001) value was found to be lower. A P wave duration-t o-amplitude ratiovalue of &gt;830 ms/mV has 61.8% sensitivity and 88.4% specificity for the prediction of the atrial fibrillation recurrence (area of under the curve [AUC], 0.727). P wave duration-to-amplitude ratio, which may be considered as an indicator of the temporal and electrical propagation of the P wave in the atria, can predict atrial fibrillation ablation recurrence.

Prediction of difficulty in cryoballoon ablation with a 3D deep learning model using polygonal mesh representation

Abstract Background Cryoballoon ablation (CBA) is a useful treatment for pulmonary vein isolation (PVI). Some cases, however, are difficult to treat and may require multiple freezing procedures and/or touch-up ablation. Although several predictors of CBA difficulty have been reported, no report has been able to assess the spatial location and morphology of the left atrium (LA) and pulmonary veins (PVs). A polygonal mesh is a collection of vertices, edges, and faces that defines the shape of a polyhedral object, and is able to represent a spatial location with a small amount of information. We hypothesized that a deep learning model that learns mesh representation datasets could more accurately detect the CBA difficulty and that we could establish a novel evaluation method in CBA. Purpose The aim of this study was to create a model to predict CBA difficulty with a 3D deep learning model using polygonal mesh representation. Methods and results All the 140 patients who underwent CBA for drug-resistant atrial fibrillation between January 2015 and January 2022 were included. A 28-mm cryoballoon (Arctic Front Advance, Medtronic) was used in all cases. We defined CBA difficulty as requiring a touch-up ablation procedure to create complete PVI. We converted the volume data in DICOM format of the computed tomography images of PVs and LA to obj file format (shown in Figure 1), which supports the definition of the geometry for object surfaces using polygonal meshes. Next, we developed a deep learning model that could learn polygonal meshes and classify whether the CBA required touch-up ablation or not. Only a training dataset is used to train the deep learning model, and finally, a test dataset is used to evaluate the model metrics. The accuracy, area under the ROC curve, recall, precision, and f1-score of the deep learning model using the test dataset was 86.5%, 87.7%, 66.7%, 75.0%, 70.6%, respectively. Conclusions We developed a 3D deep learning model that can detect a difficulty in CBA using polygonal mesh representation. By predicting difficult cases in advance, we will be able to develop strategies to increase the success rate. Funding Acknowledgement Type of funding sources: None.

Feasibility and safety of laser balloon pulmonary vein isolation in patients with prior left atrial appendage occlusion device implantation.

With the increasing adoption of left atrial appendage occlusion (LAAO) procedures and the eligibility of patients for pulmonary vein isolation (PVI) post device placement, we examined the feasibility and safety of laser balloon (LB) for PVIin patients with prior LAAO. We retrospectively examined consecutive patients with paroxysmal or persistent, drug-resistant atrial fibrillation(AF) who underwent LB PVI, after Watchman FLX device implantation at Rush University Medical Center between January 2020 and December 2021. Seven patients (four persistent and three paroxysmal) with a mean age of 64 ± 11 years, predominantly male sex (86%), were included in the study. Two (29%) patients had prior cryoablation PVI with recurrence of AF. The mean CHA2 DS2 VASc is 2.6 ± 0.5 and the mean HAS-BLED score is 3.4 ± 0.8. The mean follow-up duration was 10 ± 7 months. The mean duration between Watchman FLX device implantation and LB PVI was 592 days. Acute first pass left pulmonary vein (PV) isolation was achieved in 100% of the procedures. There were no periprocedural complications such as death, pericardial tamponade or effusion, phrenic nerve injury, PV stenosis, device perforation or embolization, or worsening peri-device leak in any of the patients. None of the patients had AF recurrence after the blanking period. LB PVI was safe and effective with 100% acute isolation of left-sided veins in patients with prior LAAO device.

Left atrial hypertension invasively measured during pulmonary vein isolation predicts atrial fibrillation recurrence.

The clinical role of left atrial hypertension (LAH) in patients with atrial fibrillation (AF) and its role as predictor in those undergoing pulmonary vein (PV) isolation is still unknown. The aim of the present study was to analyse the prevalence of LAH in patients with nonvalvular AF and preserved left ventricular ejection fraction who underwent PV isolation and its implication for AF catheter ablation. Consecutive patients with drug resistant AF who underwent PV isolation at San Maurizio Regional Hospital of Bolzano (Italy) as index procedure were retrospectively included in this analysis. Left atrial hypertension was defined as the LA mean pressure ≥15 mmHg. A total of 98 consecutive patients (71 males, 72%; mean age 60.3±8.4 years) were included in the analysis. Eleven patients (11%) underwent radiofrequency ablation and 87 (89%) cryoballoon ablation. The mean LA pressure was 11.7±5.5 mmHg; LAH occurred in 24 (24.5%) patients. At a mean follow-up of 14.6±7.1 months (median 14 months), the success rate without antiarrhythmic therapy was 71.4% (70/98; considering the blanking period). Older age, LA volume and LAH were significantly associated with early AF recurrence during the blanking period. However, only LAH independently remained a significant predictor of late AF recurrence (HR 3.02, 1.36-6.72, P=0.007). Left atrial hypertension was found in 24% of patients undergoing PV isolation and was found to be significantly related to both early and late AF recurrences.

Safety and Efficacy of Cryoballoon Ablation of Atrial Fibrillation in relation to the Patients' Age: Results from a Large Real-World Multicenter Observational Project.

Background The real-world efficacy and safety of atrial fibrillation (AF) ablation in particularly young and elderly patients are still under debate. The aim of the analysis was to investigate the effect of age on the efficacy and safety of cryoballoon ablation (CBA). Methods 2,534 patients underwent pulmonary vein isolation (PVI) by way of CBA for paroxysmal or persistent drug-resistant and symptomatic AF. The population was divided into age quartiles for evaluation, including (1) <53 years, (2) ≥53 and <61 years, (3) ≥61 and <67 years, and (4) ≥67 years. Furthermore, outcomes were analyzed in patients <41 years, ≥41 and ≤74, and >74 years old. Procedural data and complications were collected, and atrial fibrillation recurrences were evaluated during follow-up. Results Procedural-related complications (4.1%) were similar in the four subgroups according to age. At the 12-month follow-up, freedom from AF recurrence was 79.2%, 77.4%, 76.8%, and 75.2% (p=0.21), respectively (with increasing age). At 24-month follow-up, similar incidences of AF recurrence were observed in the four subgroups. When the sample was arbitrarily divided into the three age groups, a higher rate of recurrence was observed in older patients with regard to long-term follow-up (freedom from AF recurrence was 71.8% and 40.9%, respectively, at 12 and 24-month follow-up). In the univariate and multivariate analysis, age did not result in a significant predictor of AF recurrence during follow-up; however, a trend toward higher AF recurrences rates in patients ≥67 years was observed. Conclusion The data demonstrated a high degree of safety during CBA across all patient ages. Procedural performance and complications were similar between different ages; AF recurrences seem to be more frequent in patients over 74 years.

Third-generation laser balloon ablation for atrial fibrillation treatment: a multicenter experience

Abstract Background Laser balloon ablation is a promising option for performing pulmonary vein isolation (PVI) which is the cornerstone of invasive atrial fibrillation (AF) treatment. Purpose We aimed to investigate the acute efficacy and safety of the novel third-generation of the laser balloon system in an initial multicenter experience. Methods First and consecutive patients who underwent PVI with LB3 for drug-resistant paroxysmal or persistent AF at 7 Italian sites were included in this analysis. Study endpoints were acute procedural efficacy, defined as successful isolation of all identified PVs without radiofrequency touch-up, total and fluoroscopy times, and periprocedural complications. Results Our population included 86 patients (81% males, mean age 60.6±9.5 years) who underwent a procedure of PVI using LB3 between June 2020 and March 2021. Most patients had paroxysmal AF (74%) and were in sinus rhythm at the beginning of the procedure. The mean procedure time was 138±60 min; fluoroscopy time was 22±17 min and the mean ablation time was 44±40 min. Of the 313 targeted PVs, 311 (99.4%) could be isolated with first-pass LB3 application, while 2 (0.6%) required radiofrequency touchup. At the end of the procedure, all patients were in sinus rhythm and 26 (32%) received electrical cardioversion to achieve stable sinus rhythm. The total rate of major compilations was 1.2% (1/82 patients): one pericardial tamponade requiring epicardial puncture. No surgical intervention was necessary, and the patient recovered without any sequalae. There were no vascular access complications or phrenic nervy palsy. Three pinhole balloon raptures (3.5%) were observed during energy applications that required replacement of the whole system but had no effect on patient safety. Conclusions In a first multicenter experience, the LB3 system for PVI was safe with excellent acute efficacy. Funding Acknowledgement Type of funding sources: None.

Left Atrial Pressure as a Predictor of Success in Catheter Ablation of Atrial Fibrillation in a Real-Life Cohort.

Aims: The clinical role of the left atrial (LA) hypertension in patients with atrial fibrillation (AF) and its role as predictor in those undergoing pulmonary vein (PV) isolation is still unknown. The aim of the present study was to analyze the role of LA pressure in patients with nonvalvular AF who underwent PV isolation and its implication for AF catheter ablation. Methods: Consecutive patients with drug resistant AF who underwent PV isolation at San Maurizio Regional Hospital of Bolzano (Italy) as index procedure were included in this analysis. Results: A total of 132 consecutive patients (97 males, 73%; mean age 58.0 ± 13.2 years) were included in the analysis. Eleven patients (8%) underwent radiofrequency ablation and 121 (92%) cryoballoon ablation. Higher LA pressures were found in 54 patients (40.9%). At a mean follow up of 14.3 ± 8.2 months (median 12 months), the success rate without antiarrhythmic therapy was 65.9% (87/132; considering the blanking period). Female gender and continuous mean LA pressure were significantly associated with AF recurrence and remained significant on multivariable Cox analysis (respectively, HR 1.845, 1.00–3.40, p = 0.05 and HR 1.066, 1.002–1.134, p = 0.04). We identified a LA mean pressure of >15 mmHg as ideal cutoff and constructed a model to predict AF recurrence which fitted with a concordance index (C-index) of 0.65 (95% CI 0.56–0.75), logrank score p = 0.003.

Efficacy and Safety of SATAKE HotBalloon® Catheter for Treatment of Paroxysmal Atrial Fibrillation - A Post-Marketing Surveillance Study.

SATAKE HotBalloon®catheter (HBC) is a radiofrequency balloon catheter for the treatment of atrial fibrillation (AF), and was approved for use in Japan to treat drug-resistant paroxysmal AF in 2015. Post-marketing surveillance study was conducted by Toray Industries, Inc. to evaluate the efficacy and safety of HBC treatment in patients with paroxysmal AF in a real-world setting. This study is the first nation-wide survey of HBC treatment for paroxysmal AF in clinical practice in Japan. This was a single-arm, multicenter observational study with an observation period of 48 weeks after ablation. Pulmonary vein isolation and AF non-recurrence rates were evaluated and adverse events (AEs) were observed at 46 sites in Japan. An AF event was defined as recurrence of AF or re-ablation from 12 to 48 weeks after ablation. The success rate of pulmonary vein isolation was 99.0% (486/491) for patients with AF. The cumulative AF non-recurrence rate was 94.1% at 24 weeks and 87.8% at 48 weeks. AEs were found to occur 21.5% (114/530), and ablation-related AEs were found to occur 2.6% (14/530) during the study period, with the most common being pericardial effusion (0.8%, 4/530). This study demonstrates the efficacy and safety of HBC ablation in Japanese patients with recurrent symptomatic paroxysmal AF refractory to antiarrhythmic therapy.

Myocardial morphological changes and pulmonary vein catheter ablation efficacy in patients with atrial fibrillation

Aim. To study the association between morphological changes and comorbidities and atrial fibrillation (AF) catheter ablation efficacy, and to evaluate morphological predictors of AF recurrence in patients with durable pulmonary vein isolation (PVI) after catheter intervention.Material and methods. Fifty-four patients with paroxysmal/persistent AF without severe structural heart disease were enrolled in this study who underwent primary pulmonary vein cryoballoon ablation (CBA) with simultaneous implantation of an electrocardiogram loop recorder (Medtronic Reveal XT) and interatrial/interventricular septum biopsy. The follow-up duration was 12 months with scheduled 3, 6 and 12 month visits. Patients with recurrent AF were referred for redo procedure, where the PVI durability was assessed. The follow-up duration after the second procedure was also 12 months. The patients were divided into two groups: patients without recurrent AF and patients with recurrent AF after two catheter interventions.Results. In interventricular septum biopsy samples we found the morphological criteria of myocarditis in 70% of the patients (n=34). Individual morphological changes were detected in all patients. The most common types were cardiomyocyte hypertrophy — 98,1% (n= 52), overcrossing of cardiomyocytes — 77,4% (n=41) and lymphohistiocytic infiltration of the interstitium by more than 14 cells — 75,5% (n=40). Patients with persistent AF were significantly more likely to have endothelial cell swelling (55% vs 45%, p=0,022). Interstitial tissue edema was the only morphological parameter significantly associated with AF recurrence (p=0,03).Conclusion. In patients with AF and no structural heart disease who underwent drug-resistant AF cryoballoon ablation, morphological changes in the myocardium of the atria and ventricles are detected in 100% of cases. The predominant biopsy diagnosis is myocarditis. Morphological signs of the inflammatory process activity, as interstitial tissue edema are associated with the high incidence of non-venous AF. Further preoperative evaluation is needed to identify patients with non-venous atrial fibrillation, which will increase the effectiveness of interventional approach.

The Blinding Period Following Ablation Therapy for Atrial Fibrillation: Proarrhythmic and Antiarrhythmic Pathophysiological Mechanisms.

Atrial fibrillation (AF) causes heart failure, ischemic strokes, and poor quality of life. The number of patients with AF is estimated to increase to 18 million in Europe in 2050. Pharmacological therapy does not cure AF in all patients. Ablative pulmonary vein isolation is recommended for patients with drug-resistant symptomatic paroxysmal AF but is successful in only about 60%. In patients in whom ablative therapy is successful on the long term, recurrence of AF may occur in the first weeks to months after pulmonary vein ablation. The early recurrence (or delayed cure) of AF is not understood but forms the basis for the generally accepted 3-month blinding (or blanking) period after ablation therapy, which is not included in the evaluation of the eventual success rate of the procedures. The underlying pathophysiological processes responsible for early recurrence and the delayed cure are unknown. The implicit assumption of the blinding period is that the AF mechanism in this period is different from the ablation-targeted AF mechanism (ectopy from the pulmonary veins). In this review, we evaluate the temporary and long-lasting pro- and antiarrhythmic effects of each of the pathophysiological processes and interventions (necrosis, ischemia, oxidative stress, edema, inflammation, autonomic nervous activity, tissue repair, mechanical remodeling, and use of antiarrhythmic drugs) occurring in the blinding period that can modulate AF mechanisms. We propose that stretch-reducing ablation scar is a permanent antiarrhythmic mechanism that develops during the blinding period and is the reason for delayed cure.

Zero fluoroscopy cryballoon catheter ablation of paroxysmal atrial fibrillation

To assess safety and efficacy of nonfluoroscopic cryoballoon ablation, 32 patients with symptomatic drug resistant paroxysmal atrial fibrillation were treated.

Prognosis of atrial fibrillation radiofrequency ablation: Iodine-123-MIBG cardiac innervation imaging

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Russian Science Foundation BACKGROUND To date, radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) is a valuable treatment option. So far there are no clear predictors of the effectiveness of AF ablation. Nowadays, the association of cardiac sympathetic nervous system and the development and maintenance of AF has been showed. The association between сardiac sympathetic system impairment, assessed by 123I-MIBG scintigraphy and RFCA effectiveness was shown previously. However, the is lack of data concerning to prognostic value of MIBG scintigraphy in patients with different forms of AF – persistent (PAF) and long-standing persistent (LSPAF). PURPOSE To study the prognostic significance of 123I-MIBG scintigraphy in RFCA efficacy in patients with persistent and long-standing persistent AF. METHODS The study enrolled 36 patients with drug-resistant AF (both persistent (n = 20) and long-standing persistent (n = 16) forms). All patients had comorbidity as chronic coronary syndrome and hypertension. A comparison group (n = 10) was also enrolled in the study. It includes patients with chronic coronary syndrome and arterial hypertension (without arrhythmia). All patients underwent 123I-MIBG and 99mTc-MIBI scintigraphy to evaluate the cardiac sympathetic activity and myocardial perfusion, respectively. Patients with AF performed RFCA. After of 1 year follow-up patients were examined for AF recurrence. The AF recurrence was considered to be an AF of at least 30 sec duration on a 12-lead ECG or on the Holter monitoring. RESULTS During the follow-up period, AF recurrences were reported in 7 (35%) PAF patients and in 8 (50%) LSPAF patients. According to multivariate analysis only a high pre-ablation washout rate of 123I-MIBG (WR) in PAF patients (OR: 1.668; 95% CI: 1.093–2.548) and large pre-ablation 123I-MIBG/99mTc-MIBI mismatch score in LSPAF patients (OR: 2.155; 95% CI: 1.192–3.897) were independent predictors of AF recurrence after RFCA. ROC analysis indicated that in PAF patients with higher WR ≥ 20.8% (AUC: 0.968; Sensitivity: 100 %; Specificity: 45%; p &amp;lt; 0.05) and LSPAF patients with larger 123I-MIBG/99mTc-MIBI mismatch score ≥ 12.5 % (AUC: 0.942; Sensitivity: 81 %; Specificity: 28 %; p &amp;lt; 0.05) had a higher risk of AF recurrence after RFCA. CONCLUSION In AF patients the incidence of arrhythmia recurrence after RFCA is associated with impaired cardiac sympathetic nervous activity. In PAF patients the values of 123I-MIBG washout rate can predict AF recurrence. In LSPAF patients innervation/perfusion mismatch has prognostic value in terms of AF recurrence.

Efficacy of cryoablation in idiopathic and non-idiopathic atrial fibrillation patients.

Studies assessing the unicentric and prospective comparison of efficacy of cryoballoon pulmonary vein isolation in idiopathic and non-idiopathic atrial fibrillation (AF) patients are missing. The aim of this study was to compare a single procedural outcome in these subgroups of AF patients. Atotal of 208 patients with drug resistant AF were included in this study. Among them, 36 patients had idiopathic AF and 172 patients had non-idiopathic AF. The efficacy endpoint was freedom from any atrial arrhythmia lasting >30 s after a3-months blanking period. The freedom from atrial arrhythmias without antiarrhythmic drugs after 1 and 3 years of follow-up, respectively, was 85.2 % and 70.4 % in patients with idiopathic AF; and 64.6 % and 39.9 % in patients with non-idiopathic AF (p=0.021). Moreover, the success rate when analysing only paroxysmal AF patients after 1 and 3 years of follow-up, respectively, was 95.7 % and 82 % in patients with idiopathic AF; and 72.6 % and 47 % in patients with non-idiopathic AF (p=0.022). Asingle cryoballoon pulmonary vein isolation was more effective in preventing atrial arrhythmias relapses in idiopathic AF patients compared to non-idiopathic AF patients. The best efficacy outcomes were observed in patients with paroxysmal idiopathic AF (Tab. 5, Fig. 2, Ref. 25).

Echocardiographic predictors of atrial fibrillation recurrence after catheter ablation: A literature review.

Catheter ablation (CA) is a well-known treatment option for patients with symptomatic drug-resistant atrial fibrillation (AF). Multiple factors have been identified to determine AF recurrence after CA, however their predictive value is rather small. Identification of novel predictors of CA outcome is therefore of primary importance to reduce health costs and improve long-term results of intervention. The recurrence of AF following CA is related to severity of left ventricular (LV) dysfunction, extent of atrial dilatation and fibrosis. The aim of this paper was to present and discuss the latest studies on the utility of echocardiographic parameters in terms of CA effectiveness in patients with paroxysmal and persistent AF. PubMed, Google Scholar, EBSCO databases were searched for studies reporting echocardiographic preprocedural predictors of AF recurrence after CA. LV systolic and diastolic function, as well as atrial size, strain and dyssynchrony were taken into consideration. Twenty one full-text articles were analyzed, including three meta-analyses. Several echocardiographic parameters have been reported to determine a risk of AF recurrence after CA. There are conventional methods that measure left atrial size and volume, LV ejection fraction, parameters assessing LV diastolic dysfunction, and methods using more innovative technologies based on speckle tracking echocardiography to determine left atrial synchrony and strain. Each of these parameters has its own predictive value. Regarding CA effectiveness, every patient has to be evaluated individually to estimate the risk of AF recurrence, optimally using a combination of several echocardiographic parameters.