Publications by authors named "Richard Snowdon"

Article Synopsis
  • The study aimed to compare the effectiveness of manual compression (MC) and two suture-based techniques (Fo8 and modified Fo8) for femoral venous haemostasis after electrophysiology procedures, hypothesizing that Fo8 would lead to better short-term bleeding outcomes than MC.
  • In a sample of 1,089 patients, Fo8 showed significantly fewer major and minor complications compared to MC, particularly in those receiving anticoagulation during the procedure.
  • The findings suggest that the Fo8 technique significantly reduces the risk of access site complications after these procedures, indicating it may be a preferred method for achieving haemostasis.
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Background: Patients who have recurrent atrial fibrillation (AF) following redo catheter ablation may eventually be managed with a pace-and-ablate approach, involving pacemaker implant followed by (AVNA). We sought to determine which factors would predict subsequent AVNA in patients undergoing redo AF ablation.

Methods: We analyzed patients undergoing redo AF ablations between 2013 and 2019 at our institution.

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Background: With the exponential growth of catheter ablation for atrial fibrillation (AF), there is increasing interest in associated health care costs. Pulsed field ablation (PFA) using a single-shot pentaspline multielectrode catheter has been shown to be safe and effective for AF ablation, but its cost efficiency compared to conventional thermal ablation modalities (cryoballoon [CB] or radiofrequency [RF]) has not been evaluated.

Objective: The purpose of this study was to compare cost, efficiency, effectiveness, and safety between PFA, CB, and RF for AF ablation.

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Background: No study has assessed the durability of pulmonary vein isolation (PVI) with radiofrequency (RF) and cryoballoon (CB) in patients with persistent atrial fibrillation. These data are especially lacking for those with significantly diseased left atria (LA).

Objectives: The goals of this study were to assess PVI durability in patients with significant LA disease and to compare reconnection rates between RF and CB.

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Introduction: Pulmonary vein isolation (PVI) is often performed under general anaesthesia (GA) or deep sedation. Anaesthetic availability is limited in many centers, and deep sedation is prohibited in some countries without anaesthetic support. Very high-power short duration (vHPSD-90W/4 s) PVI using the Q-Dot catheter is generally well tolerated under mild conscious sedation (MCS) though an understanding of catheter stability and long-term effectiveness is lacking.

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Introduction: Atrial fibrillation (AF) is associated with endothelial damage/dysfunction. Herein, we tested the hypothesis that brachial artery flow-mediated dilation (FMD) is superior in AF patients taking apixaban compared to warfarin.

Methods: AF patients on apixaban (n = 46; 67 [7] years; mean [standard deviation]; 15 women) and warfarin (n = 27; 73 [9] years (p < 0.

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Background: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Despite promising success rates, redo ablation is sometimes required. At redo, PVs may be found to be isolated (silent) or reconnected.

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Background: Ultrasound (US) is being increasingly used to guide vascular access for electrophysiology (EP) procedures in many centres. Nonetheless, the incidence and predictors of vascular complications in the US era are limited. In this study, we describe our experience of vascular access-related complications associated with EP procedures which were performed with the routine use of US-guided vascular access.

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Background: Very high power short duration (vHPSD) radiofrequency ablation (RFA) may reduce ablation times and improve patient tolerability, permitting pulmonary vein isolation (PVI) under mild conscious sedation (mCS) and promoting same day discharge (SDD).

Methods: First, a retrospective feasibility study was performed at 2 tertiary cardiac centres in the UK. Consecutive cases of first-time PVI using vHPSD ablation with 90 W lesions for up to 4 s were compared against cases performed using standard RF (sRF) and cryoballoon (Cryo) therapy.

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Background: Effects of the COVID-19 pandemic on cardiac rhythm management (CRM) services remain poorly quantified.

Objective: To describe the impact of COVID-19 on specialist CRM centers in the United Kingdom (UK).

Methods: Two-center study involving the Liverpool Heart and Chest Hospital NHS Foundation Trust and Royal Papworth Hospital NHS Foundation Trust.

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Objective: Atrial fibrillation (AF) ablation services were significantly affected by the COVID-19 pandemic. We aimed to evaluate a symptom-based clinician prioritisation scheme for waiting list management compared with patient-completed quality of life (QoL) scores. We also sought to understand factors influencing QoL, particularly the impact of COVID-19, on patients awaiting AF ablation, via a bespoke questionnaire.

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Background: Ablation index (AI)-guided ablation for posterior wall isolation (PWI) using high-power, short-duration remains untested. We sought to evaluate the acute outcomes of AI-guided 50 W ablation vs. conventional ablation, and investigate the differences in relationship between contact force (CF), time and AI in both groups.

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Cardiac sarcoidosis and cystic fibrosis (CF) are both rare conditions and their co-existence has not previously been noted in adults. For the first time we report a case of isolated cardiac sarcoidosis in a woman with CF, and discuss the possible combined aetiological factors. As the life expectancy of people with CF continues to increase, clinicians should be aware of the emergence of concomitant inflammatory conditions typically diagnosed in adulthood, and the diagnostic challenges this may present.

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Introduction: Radiofrequency catheter ablation is a cornerstone of treatment for many cardiac arrhythmias. Progression in three-dimensional mapping and contact-force sensing technologies have improved our capability to achieve success, but challenges still remain.

Methods: In this article, we discuss the importance of overall circuit impedance in radiofrequency lesion formation.

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Aims: The safety of Ablation Index (AI)-guided 50 W ablation for atrial fibrillation (AF) remains uncertain, and mid-term clinical outcomes have not been described. The interplay between AI and its components at 50 W has not been reported.

Methods And Results: Eighty-eight consecutive AF patients (44% paroxysmal) underwent AI-guided 50 W ablation.

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Background: The feasibility of significant weight reduction in a specialist arrhythmia service, and its impact on atrial fibrillation (AF) ablation outcomes are unclear. We aimed to assess these factors in a real-world cohort in the United Kingdom.

Methods: Patients from one specialized arrhythmia clinic were instructed to follow the "Intermittent Fasting 5:2 diet" ("diet group", n = 50), and their outcomes were compared to a propensity matched cohort who received no specific dietary advice ("control group", n = 42).

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Background: Catheter ablation for atrial fibrillation (AF) traditionally requires the use of circular mapping catheter (CMC) for pulmonary vein isolation (PVI). This study aimed to assess the feasibility and effectiveness of a CMC-free approach for AF ablation performed by a contiguous optimized (CLOSE) ablation protocol.

Methods: A CLOSE-guided and CMC-free PVI protocol with a single transseptal puncture was attempted in 67 patients with AF.

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Objectives: A new electroanatomic mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) using a 64-electrode mapping basket is now available; we systematically assessed its use in complex congenital heart disease (CHD).

Background: The incidence of atrial arrhythmias post-surgery for CHD is high. Catheter ablation has emerged as an effective treatment, but is hampered by limitations in the mapping system's ability to accurately define the tachycardia circuit.

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Background: Atrial fibrillation (AF) ablation is a complex procedure, generally requiring at least one overnight hospital stay. We investigated the safety and feasibility of early mobilization and same-day discharge following streamlined peri-ablation management for AF.

Methods: From 2014, we offered same-day discharge to selected patients who underwent uncomplicated AF ablation on the morning lists, with ultrasound-guided femoral access, uninterrupted warfarin or minimal interruption in novel oral anticoagulants, and reversal of intraprocedural heparin with protamine.

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Purpose: Adverse left atrial (LA) remodeling is known to be associated with persistent atrial fibrillation (PeAF). The time course and pattern of reversal of LA remodeling following catheter ablation is poorly understood. We aimed to evaluate LA chamber volumes and dimensions, LA conduction velocities, and LA bipolar voltages at baseline and at 2 months after catheter ablation for PeAF.

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Aims: Video-assisted thoracoscopic surgery (VATS) ablation has been advocated as a treatment option for non-paroxysmal atrial fibrillation (AF) in recent guidelines. Real-life data on its safety and efficacy during a centre's early experience are sparse.

Methods And Results: Thirty patients (28 persistent/longstanding persistent AF) underwent standalone VATS ablation for AF by an experienced thoracoscopic surgeon, with the first 20 cases proctored by external surgeons.

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Background Catheter ablation for persistent atrial fibrillation (AF) is associated with less favorable outcomes than for paroxysmal AF. Substrate modification is often added to pulmonary vein isolation (PVI) to try to improve success rates. Recent studies have shown improved clinical outcomes with use of regional ablation index (AI) targets for PVI.

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Introduction: Demonstration of exit block after pulmonary vein isolation (PVI) is the cornerstone of ablation for atrial fibrillation (AF). It requires the demonstration of local pulmonary vein (PV) capture and absence of conduction to the atrium but is often challenging due to the inability to see local paced PV-evoked potentials. We retrospectively examined the ability of adenosine to augment this technique during CARTO-based radiofrequency ablation procedures.

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Background: A large number of SCN5A variants have been reported to underlie Brugada syndrome (BrS). However, the evidence supporting individual variants is highly heterogeneous.

Objective: We systematically re-evaluated all SCN5A variants reported in BrS using the 2015 American college of medical genetics and genomics and the association for molecular pathology (ACMG-AMP) guidelines.

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