Publications by authors named "Timothy Betts"

Article Synopsis
  • Inappropriate therapy (IAT) is a significant issue associated with implantable cardiac defibrillator (ICD) therapy, particularly highlighted in early subcutaneous ICD (S-ICD) studies which showed high rates of inappropriate shocks (IAS).
  • The PRAETORIAN trial, an international study with 849 patients, found no major differences in IAT and IAS rates between S-ICD and transvenous ICD (TV-ICD) groups, as both groups had similar cumulative incidences.
  • Key predictors for IAT varied between the two groups, with TV-ICD patients experiencing IAT mainly from supraventricular tachycardias, while S-ICD patients faced issues from cardiac oversensing
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Article Synopsis
  • The S-ICD was created to eliminate lead-related issues found in the TV-ICD, as it is an external device that sits under the skin rather than using leads inside the body.
  • This analysis comes from the PRAETORIAN trial, where patients were randomly assigned to either S-ICD or TV-ICD and assessed for quality of life through various questionnaires at different stages.
  • Results showed no significant differences in physical and mental well-being between the groups, but patients who experienced a shock recently reported lower social functioning and emotional health compared to those who did not.
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Introduction: The novel Confirm Rx™ implantable cardiac monitor (ICM) with SharpSense™ technology incorporates a new P-wave discriminator designed to improve AF detection. This study aimed to evaluate the diagnostic performance of the Confirm Rx™ ICM in detecting AF episodes of varying durations.

Methods: We conducted a multicenter retrospective analysis of consecutive patients implanted with a Confirm Rx™ ICM (v1.

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Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia associated with significant morbidity and mortality. Managing risk of stroke and AF burden are pillars of AF management. Atrial geometry has long been recognized as a useful measure in achieving these goals.

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Article Synopsis
  • About 40% of heart failure patients eligible for cardiac resynchronization therapy (CRT) do not respond or cannot be treated, highlighting the need for alternative options.
  • The SOLVE-CRT study evaluated the safety and effectiveness of a new leadless left ventricular pacing system for high-risk patients or those who had unsuccessful CRT using conventional methods.
  • The study involved 183 participants, primarily older males, and was stopped early due to positive results showing improvements in safety and a decrease in heart chamber size.
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Article Synopsis
  • - Study aimed to determine factors influencing early mortality after left atrial appendage occlusion (LAAO) to improve patient selection and cost-effectiveness for stroke prevention.
  • - Analyzed data from 1,020 patients, finding a 2-year mortality rate of 16.4%, with 50% of deaths attributed to non-cardiovascular causes, and identified six key predictors of mortality including age and heart failure.
  • - Concluded that as the number of risk factors in patients increased, the mortality rate rose significantly, underscoring the need for careful patient selection for LAAO procedures.
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Aims: Patients with persistent atrial fibrillation (AF) experience 50% recurrence despite pulmonary vein isolation (PVI), and no consensus is established for secondary treatments. The aim of our i-STRATIFICATION study is to provide evidence for stratifying patients with AF recurrence after PVI to optimal pharmacological and ablation therapies, through in silico trials.

Methods And Results: A cohort of 800 virtual patients, with variability in atrial anatomy, electrophysiology, and tissue structure (low-voltage areas, LVAs), was developed and validated against clinical data from ionic currents to electrocardiogram.

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Aims: The trials upon which recommendations for the use of cardiac resynchronization therapy (CRT) in heart failure used optimal medical therapy (OMT) before sodium-glucose co-transporter 2 inhibitors (SGLT2i). Moreover, the SGLT2i heart failure trials included only a small proportion of participants with CRT, and therefore, it remains uncertain whether SGLT2i should be considered part of OMT prior to CRT.

Methods And Results: We compared electrocardiogram (ECG) and echocardiographic responses to CRT as well as hospitalization and mortality rates in consecutive patients undergoing implantation at a large tertiary centre between January 2019 to June 2022 with and without SGLT2i treatment.

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Background: The PRAETORIAN score estimates the risk of failure of subcutaneous implantable cardioverter-defibrillator (S-ICD) therapy by using generator and lead positioning on bidirectional chest radiographs. The PRospective randomized compArative trial of subcutanEous implanTable cardiOverter-defibrillatoR ImplANtation with and without DeFibrillation Testing (PRAETORIAN-DFT) investigates whether PRAETORIAN score calculation is noninferior to defibrillation testing (DFT) with regard to first shock efficacy in spontaneous events.

Objective: This prespecified subanalysis assessed the predictive value of the PRAETORIAN score for defibrillation success in induced ventricular arrhythmias.

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Introduction: Fusion pacing requires correct timing of left ventricular pacing to right ventricular activation, although it is unclear whether this is maintained when atrioventricular (AV) conduction changes during exercise. We used cardiopulmonary exercise testing (CPET) to compare cardiac resynchronization therapy (CRT) using fusion pacing or fixed AV delays (AVD).

Methods: Patients 6 months post-CRT implant with PR intervals < 250 ms performed two CPET tests, using either the SyncAV™ algorithm or fixed AVD of 120 ms in a double-blinded, randomized, crossover study.

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Aims: In patients with a low AF burden and long periods of sinus rhythm, 'pill-in-the-pocket' oral anticoagulation (OAC) may, taken as needed in response to AF episodes, offer the same thromboembolic protection as continuous, life-long OAC, while reducing bleeding complications at the same time. The purpose of this study is to systematically summarise available evidence pertaining to the feasibility, safety and efficacy of pill-in-the-pocket OAC.

Methods: Medline and Embase were searched from inception to July 2022 for studies adopting a pill-in-the-pocket OAC strategy in AF patients guided by daily rhythm monitoring (PROSPERO/CRD42020209564).

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Aims: Electro-anatomical mapping may be critical to identify atrial fibrillation (AF) subjects who require substrate modification beyond pulmonary vein isolation (PVI). The objective was to determine correlations between pre-ablation mapping characteristics and 12-month outcomes after a single PVI-only catheter ablation of AF.

Methods And Results: This study enrolled paroxysmal AF (PAF), early persistent AF (PsAF; 7 days-3 months), and non-early PsAF (>3-12 months) subjects undergoing de novo PVI-only radiofrequency catheter ablation.

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Aims: RECOVER AF evaluated the performance of whole-chamber non-contact charge-density mapping to guide the ablation of non-pulmonary vein (PV) targets in persistent atrial fibrillation (AF) patients following either a first or second failed procedure.

Methods And Results: RECOVER AF was a prospective, non-randomized trial that enrolled patients scheduled for a first or second ablation retreatment for recurrent AF. The PVs were assessed and re-isolated if necessary.

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While sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) is due to arrhythmias, the guidelines for prediction of SCD are based solely on non-electrophysiological methods. This study aims to stimulate thinking about whether the interests of patients with HCM are better served by using current, 'risk factor', methods of prediction or by further development of electrophysiological methods to determine arrhythmic risk. Five published predictive studies of SCD in HCM, which contain sufficient data to permit analysis, were analysed to compute receiver operating characteristics together with their confidence bounds to compare their formal prediction either by bootstrapping or Monte Carlo analysis.

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Background: Intracardiac echocardiography (ICE) is increasingly used to guide left atrial appendage closure (LAAC).

Objectives: The aim of this study was to investigate the efficacy and safety of ICE-guided LAAC with the Watchman FLX device.

Methods: The ICE LAA (I Can See Left Atrial Appendage) study was a prospective, multicenter study with independent adjudication of echocardiographic data by a core laboratory and clinical events by a clinical events committee.

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Background: New-onset atrial fibrillation (NOAF) is common during critical illness and is associated with poor outcomes. Many risk factors for NOAF during critical illness have been identified, overlapping with risk factors for atrial fibrillation in patients in community settings. To develop interventions to prevent NOAF during critical illness, modifiable risk factors must be identified.

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Article Synopsis
  • The subcutaneous implantable cardioverter-defibrillator (S-ICD) was designed to reduce complications linked to traditional transvenous ICD (TV-ICD) therapy, such as lead issues and infections.
  • The PRAETORIAN trial, which included 849 patients, found that while both devices had complications, the S-ICD group experienced fewer lead-related issues and systemic infections compared to the TV-ICD group.
  • The trial results indicate that complications from the TV-ICD were more severe, often requiring invasive procedures, highlighting the S-ICD as a safer alternative for patients needing ICD therapy.
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The implantable cardioverter-defibrillator (ICD) is a proven treatment for preventing sudden cardiac death. Transvenous leads are associated with significant mortality and morbidity, and the subcutaneous ICD (S-ICD) addresses this. However, it is not without limitations, in particular the absence of anti-tachycardia pacing.

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Results from catheter ablation for persistent AF are suboptimal, with no strategy other than pulmonary vein isolation showing clear benefit. Recently employed empirical strategies beyond pulmonary vein isolation involve widespread atrial ablation in all patients and do not take into account patient-specific differences in AF mechanisms or phenotype. Charge density mapping using the non-contact AcQMap system (Acutus Medical) allows visualisation of whole-chamber activation during AF and reveals localised patterns of complex activation thought to represent important mechanisms for AF maintenance that can be targeted with focal ablation.

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Although cardiac resynchronization therapy (CRT) has become well established in the treatment of heart failure, the management of patients who do not respond after CRT remains a key challenge. This review will summarize what we have learned about non-responders over the last 20 years and discuss methods for optimizing response, including the introduction of novel therapies.

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Aims: Catheter ablation for atrial fibrillation (AF) has historically required inpatient admission post-procedure, but same-day discharge (SDD) has recently been reported. We aimed to assess the efficacy and safety of SDD compared with overnight stay (OS) post-ablation.

Methods And Results: We performed a systematic search of the PubMed database.

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Background Adenosine shortens action potential duration and refractoriness and provokes atrial fibrillation. This study aimed to evaluate the effect of adenosine on mechanisms of wavefront propagation during atrial fibrillation. Methods and Results The study included 22 patients undergoing catheter ablation for persistent atrial fibrillation.

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Background: Left atrial appendage occlusion (LAAO) is recommended for patients with atrial fibrillation at increased stroke risk, where effective long-term oral anticoagulation (OAC) is not feasible. In order to assess long-term safety of LAAO with aspirin monotherapy or no therapy, we aimed to report on patients with the Watchman LAAO device (Boston Scientific) once postimplantation intensified antiplatelet or anticoagulation therapy is discontinued.

Methods: A total of 1025 patients scheduled for elective LAAO therapy prospectively consented for participation in the EWOLUTION registry; 1005 patients received a successful implant and were followed for 2 years.

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Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a growing public health epidemic. In the UK, over 1.3 million people have a diagnosis of AF and an estimated 400,000 remain undiagnosed.

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Aims: SuperMap is a novel non-contact algorithm for the mapping of organized atrial arrhythmias. We prospectively evaluated SuperMap during mapping and ablation of atrial tachycardias (ATs) and paced rhythms and compared to conventional high-density contact mapping.

Methods And Results: Consecutive patients undergoing SuperMap guided ablation of pre-existing ATs or AT developed during atrial fibrillation ablation procedures were included together with maps obtained during pacing to assess block in linear lesions.

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