Publications by authors named "Sebastien Knecht"

Background: Sudden cardiac death (SCD) is generally associated with life-threatening ventricular arrhythmias. Supraventricular arrhythmias are an accepted cause of SCD in Wolff-Parkinson-White syndrome and complex congenital heart disease. However, the role of atrial tachyarrhythmias (ATAs) in SCD in patients with structurally normal hearts is unclear.

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  • Macroreentry is the main cause of typical and atypical flutter, but many questions about it remain unanswered, prompting a study that uses topology to investigate atrial tachycardia activation patterns.
  • Researchers utilized a computational model resembling a closed sphere with holes to analyze cases of tachycardia, focusing on activation maps and ablation responses in 131 clinical cases.
  • The study's findings suggest that reentrant activity on closed surfaces consistently shows paired rotation, and through mathematical principles, they established a framework to better understand flutter and its treatment outcomes.
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  • Achieving effective mitral isthmus (MI) block using only radiofrequency (RF) catheter ablation is often difficult, but using vein of Marshall (VoM) ethanolization creates more durable lesions that improve results.
  • A study of 37 patients without VoM showed a 97% success rate for achieving MI block compared to only 65% in a control group with VoM assessed, indicating a significant effectiveness difference.
  • The findings imply that the presence of VoM might play a critical role in the challenges faced when trying to achieve MI block through traditional methods.
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Persistent atrial fibrillation (AF) is a diverse condition that includes various subtypes and underlying causes of arrhythmia. Progress made in catheter ablation technology in recent years has significantly enhanced the durability of ablation. Despite these advances however, the effectiveness of ablation in treating persistent AF is still relatively modest.

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  • Pulsed field ablation (PFA) is a new method for treating atrial fibrillation (AF) that focuses on ablating heart tissue while minimizing harm to nearby structures.
  • In the MANIFEST-17K study, data from 106 centers involved 17,642 patients and showed no serious complications like esophageal damage, with only a 1% major complication rate.
  • The results suggest that PFA has a strong safety profile and may change how AF is treated, compared to traditional thermal ablation methods.
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Background: Idiopathic ventricular fibrillation (IVF) can be associated with undetected distinct conditions such as microstructural cardiomyopathic alterations (MiCM) or Purkinje (Purk) activities with structurally normal hearts.

Objectives: This study sought to evaluate the characteristics of recurrent VF recorded on implantable defibrillator electrograms, associated with these substrates.

Methods: This was a multicenter collaboration study.

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Introduction: Esophageal safety following radiofrequency (RF) left atrial (LA) linear ablation has not been established. To determine the esophageal safety profile of LA linear RF lesions, we performed systematic esophagogastroduodenoscopy in all patients with intraesophageal temperature rise (ITR) ≥ 38.5°C.

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Background: Left ventricular (LV) summit arrhythmias account for up to 14% of LV arrhythmias. The ablation of LV summit arrhythmias is challenging, as testified by the fact that radiofrequency (RF) catheter ablation failure is frequent. Retrograde coronary venous ethanol infusion has been proposed as an alternative approach for the ablation of LV summit arrhythmias.

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  • This study looked at how well an automatic program can check if certain veins in the heart are isolated during a procedure called pulmonary vein isolation (PVI), which is used to treat a heart condition called atrial fibrillation.
  • The researchers compared this program's results to expert doctors' opinions by gathering data from 89 patients across four hospitals.
  • The program performed really well, with scores showing it was accurate over 86% of the time in confirming if the veins were isolated properly.
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  • * The ligament of Marshall is identified as a source of AF triggers and has nerve fibers that maintain AF, suggesting it plays a critical role in the condition's persistence.
  • * Ethanol infusion into the Vein of Marshall shows promise in reducing arrhythmia recurrence post-ablation, but further randomized trials are necessary to evaluate its long-term effectiveness.
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  • The BEAT PAROX-AF trial is a European study comparing pulsed field ablation (PFA) with radiofrequency (RF) ablation for treating drug-resistant paroxysmal atrial fibrillation (AF), focusing on efficacy and safety.
  • A total of 292 participants were randomly assigned to either PFA or RF using specific protocols to measure outcomes such as the recurrence of atrial arrhythmia and serious adverse events.
  • The study began in December 2021 and will conclude recruitment in January 2024, with results expected to be published in mid-2025, aiming to improve treatment strategies for patients with paroxysmal AF.
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Aims: Pulsed field ablation (PFA) is a promising ablation technique for pulmonary vein isolation (PVI) with appealing advantages over radiofrequency (RF) including speed, tissue selectivity, and the promise of enhanced durability. In this study, we determine the procedural performance, efficacy, safety, and durability of PFA and compare its performance with a dataset of optimized RF ablation.

Methods And Results: After propensity score matching, we compared 161 patients who received optimized RF-guided PVI in the PowerPlus study (CLOSE protocol) with 161 patients undergoing PFA-guided PVI for paroxysmal or persistent atrial fibrillation (AF; pentaspline basket catheter).

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Background: Early recurrence of atrial tachyarrhythmia (ERAT) is associated with ablation-induced proarrhythmogenic inflammation; however, existing studies used intermittent monitoring or nonoptimized radiofrequency (RF) applications (noncontiguous or without ablation index target value).

Objective: The purpose of this study was to investigate the relationship between ERAT and late recurrence based on insertable cardiac monitor (ICM) data.

Methods: We compiled data from Close-To-Cure and Close Maze studies, which enrolled patients who underwent RF ablation for paroxysmal or persistent atrial fibrillation (AF).

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Background: In patients with persistent atrial fibrillation (PersAF), catheter ablation aiming for pulmonary vein isolation (PVI) is associated with moderate clinical effectiveness. We investigated the benefit of continuing previously ineffective class 1C or 3 antiarrhythmic drug therapy (ADT) in the setting of a standardized PVI-only ablation strategy.

Methods: In this multicenter, randomized controlled study, patients with PersAF (≥7 days and <12 months) despite ADT were prospectively randomized 1:1 to PVI with ADT continued versus discontinued beyond the blanking period (ADT ON versus ADT OFF).

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Background: Persistent shock-resistant atrial fibrillation (AF) is a challenging entity, with modest results from catheter ablation according to conventional survival analysis.

Objectives: The 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).

Methods: Patients with drug-resistant ongoing persistent AF and at least 1 previous failed cardioversion were implanted with an ICM 2 months before the procedure.

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Background: Very high-power, short-duration (90-W/4-second) ablation for pulmonary vein isolation (PVI) may reduce procedural times. However, shorter applications with higher power may impact lesion quality.

Objectives: In this multicenter, randomized controlled trial, the authors compared procedural efficiency, efficacy, and safety of PVI using 90-W/4-second ablation to 35/50-W ablation.

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Aims: Atrial fibrillation (AF) occurs frequently after mitral valve (MV) surgery. This study aims to evaluate the efficacy and long-term clinical outcomes after the first AF ablation in patients with prior MV surgery.

Methods: Sixty consecutive patients with a history of MV surgery without MAZE referred to three European centers for a first AF ablation between 2007 and 2017 (group 1) were retrospectively enrolled.

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Recurrent atrial tachycardia (AT) is a common phenomenon after catheter ablation for AF, particularly in the setting of additional substrate ablation, with many studies demonstrating gap-related macro re-entrant AT (predominantly mitral and roof dependent) to be the dominant mechanism. Although multiple inducible ATs after ablation of the clinical AT are commonly described at repeat procedures, the optimal ablation strategy, and procedural endpoints are unclear in this setting. A recent randomized study addressing the question of non-inducibility as a procedural endpoint demonstrated no additional benefits to the ablation of all induced, non-clinical ATs, but it was limited by small numbers and high rates of non-inducibility.

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The superior vena cava (SVC) is well described as one of the most common non-pulmonary vein (PV)-triggers for atrial tachyarrhythmias (ATA). In our study we evaluated a standardized approach for electrical isolation of the SVC from the right atrium using a horseshoe-shaped lesion set with optimized and contiguous ostial RF lesions. The results are promising, demonstrating a very high rate of acute SVC isolation in a safe and time efficient manner (mostly less than 10 min).

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