1,720,997 research outputs found
Global Substrate Mapping and Targeted Ablation with Novel Gold-tip Catheter in De Novo Persistent AF
Get PDFResults 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. In this review, the authors outline the fundamentals of this technology, the initial data exploring the mechanistic role of activation patterns seen and the application to ablation of persistent AF
High-density mapping of left atrial endocardial activation during sinus rhythm and coronary sinus pacing in patients with paroxysmal atrial fibrillation
No full textIntroduction: This study was designed to record global high-density maps of left atrial endocardial activation during sinus rhythm and coronary sinus pacing.Method and Results: Noncontact mapping of the left atrium was performed in nine patients with paroxysmal atrial fibrillation undergoing pulmonary vein ablation procedures. High-density isopotential and isochronal activation maps were superimposed on three-dimensional reconstructions of left atrial geometry. Mapping was repeated during pacing from sites within the coronary sinus. Earliest left atrial endocardial activation occurred anterior to the right pulmonary veins in seven patients and on the anterosuperior septum in two patients. A line of conduction block was seen in the posterior wall and inferior septum in all patients. The direction of activation in the left atrial myocardium overlying the coronary sinus was different from the electrogram sequence in the coronary sinus catheter in 6 of 9 patients. During coronary sinus pacing, activation entered the left atrium a mean (SD) of 41 (13) ms after the pacing stimulus at a site 12 (10) mm from the endocardium overlying the pacing electrode. Lines of conduction block were present in the posterior wall and inferior septum.Conclusion: In patients with paroxysmal atrial fibrillation, lines of conduction block are present in the left atrium during sinus rhythm and coronary sinus pacing. Electrograms recorded in the coronary sinus infrequently correspond to the direction of activation in the overlying left atrial myocardium
NICE atrial fibrillation guideline snubs wearable technology: a missed opportunity?
No full textAtrial 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. AF-related strokes account for a quarter of all strokes and, as AF episodes are often asymptomatic, are still often the first manifestation of AF. Early diagnosis and initiation of oral anticoagulation, where appropriate, may prevent some of these thromboembolic strokes. Public Health England is committed to decrease the incidence of AF-related strokes and has sponsored initiatives aimed at improving AF detection by promoting the uptake of wearable technologies. However, the National Institute for Health and Care Excellence (NICE) has not recommended wearable technology in their recent AF diagnosis and management guidelines (NG196). Diagnostic accuracy of single-lead electrocardiography (ECG) generated by the latest iteration of wearable devices is excellent and, in many cases, superior to general practitioner interpretation of the 12-lead ECG. High-quality ECG from wearable devices that unequivocally shows AF can expedite AF detection. Otherwise, there is a real risk of delaying AF diagnosis with the potential of devastating consequences for patients and their families.</p
PO-05-156 software automation for delivery of pill-in-pocket anticoagulation (PIPOAC): experience from Oxford, UK
No full textBackground: PIPOAC is an emerging approach for suitable AF patients (infrequent AF episodes, short episode duration, lower CHA2DS2-VASC).PIPOAC is taken during AF and temporarily after. Time from AF onset to starting PIPOAC must be minimised to allow prompt anticoagulation.Continuous monitoring for AF onset is achieved using implantable cardiac monitors (ICM). ICM transmission surveillance and patient communication must currently be performed by healthcare staff.A continuous automated process would reduce clinical workload and ensure PIPOAC is commenced promptly.Objective: design software to continuously screen Medtronic Carelink platform to view transmissions from patient LINQ II devices. Program must trigger SMS alert to patients for AF episodes over 60 minutes (as per our PIPOAC criteria).Methods: program code written using .NET open-source application between 2021-24 in four phases. Code improvements made over time to deal with minor bugs, unexpected scenarios, upgrades to .NET, and changes to Carelink website.Program decision tree for new transmissions shown (Image 1).Results: software test over 35 days between Oct and Dec 2024 including 32 patients monitored by LINQ II.Phase one: AF episodes in seven patients. 91.7% of alerts delivered (Table 1). Three AF episodes missed in one patient who triggered transmissions using symptom activator. The program didn't recognize “AF (Symptom)” episodes. Code updated to recognize this category for phase two.Phase two: AF episodes in five patients. 100% of alerts delivered, none missed.Median time from AF episode onset to SMS 04:11 hours.Conclusion: an automated system can effectively and quickly deliver patient alerts for AF. This approach could facilitate wider use of PIPOAC
Transvenous or subcutaneous implantable cardioverter defibrillator: a review to aid decision-making.
No full textThe 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. The decision of which device is most suitable for an individual patient is often complex. Here, we review the relative merits and weaknesses of both the transvenous and S-ICD. We summarise the available evidence for each device in particular patient cohorts, namely: ischaemic and non-ischaemic cardiomyopathy, idiopathic ventricular fibrillation, Brugada syndrome, long QT syndrome, arrhythmogenic right ventricular cardiomyopathy, and hypertrophic cardiomyopathy
Identifying extra pulmonary vein targets for persistent atrial fibrillation ablation: bridging advanced and conventional mapping techniques
Get PDFAims: Advanced technologies such as charge density mapping (CDM) show promise in guiding adjuvant ablation in patients with persistent atrial fibrillation (AF); however, their limited availability restricts widespread adoption. We sought to determine whether regions of the left atrium containing CDM-identified pivoting and rotational propagation patterns during AF could also be reliably identified using more conventional contact mapping techniques. Methods and results: Twenty-two patients undergoing de novo ablation of persistent AF underwent both CDM and electroanatomic voltage mapping during AF and sinus rhythm with multiple pacing protocols. Through the use of a left atrium statistical shape model, the location of distinctive propagation patterns identified by CDM was compared with low-voltage areas (LVAs) and regions of slow conduction velocity (CV). Neither LVA nor CV mapping during paced rhythms reliably identified regions containing CDM propagation patterns. Conduction velocity mapping during AF did correlate with these regions (ρ = −0.63, P < 0.0001 for pivoting patterns; ρ = −0.54, P < 0.0001 for rotational patterns). These propagation patterns consistently occurred in two specific anatomical regions across patients: the anteroseptal and inferoposterior walls of the left atrium. Conclusion: Mapping techniques during paced rhythms do not reliably correspond with regions of CDM-identified propagation patterns in persistent AF. However, these propagation patterns are consistently observed in two specific anatomical regions, suggesting a predisposition to abnormal electrophysiological properties. While further research is needed, these regions may serve as promising targets for empirical ablation, potentially reducing the reliance on complex mapping techniques
Radiofrequency ablation of idiopathic ventricular fibrillation guided by noncontact mapping
No full textA 32-year-old man with idiopathic ventricular fibrillation and an implantable cardioverter defibrillator presented during a ventricular fibrillation storm. Frequent monomorphic ventricular ectopics with left bundle branch block morphology were documented, some of which initiated fibrillation. He underwent noncontact mapping of the right ventricle, during which the ventricular ectopics were mapped to a site in the free wall displaying a diastolic potential 80 ms before ectopic QRS onset. Following three radiofrequency energy applications, the ectopics were abolished. After 11-month follow-up, he has experienced no further arrhythmias. Noncontact mapping may identify ablatable triggers of ventricular fibrillation and lead to successful outcomes even when only single ectopics are present
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Impact of Adenosine on Wavefront Propagation in Persistent Atrial Fibrillation: Insights From Global Noncontact Charge Density Mapping of the Left Atrium
No full textBACKGROUND: 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. Left atrial mapping was performed using the AcQMap charge density system before and after administration of intravenous adenosine at 1 or more of 3 time points during the procedure (before pulmonary vein isolation, after pulmonary vein isolation, and after nonpulmonary vein isolation ablation). Wave‐front propagation patterns were evaluated allowing identification and quantification of localized rotational activation (LRA), localized irregular activation, and focal firing. Additional signal processing was performed to identify phase singularities and calculate global atrial fibrillation cycle length and dominant frequency. A total of 35 paired maps were analyzed. Adenosine shortened mean atrial fibrillation cycle length from 181.7±14.3 to 165.1±16.3, (mean difference 16.6 ms; 95% CI, 11.3–21.9, P<0.0005) and increased dominant frequency from 6.0±0.7 Hz to 6.6±0.8 Hz (95% CI, 0.4–0.9, P<0.0005). This was associated with a 50% increase in the number of LRA occurrences (16.1±7.6–24.2±8.1; mean difference 8.1, 95% CI, 4.1–12, P<0.0005) as well as a 20% increase in the number of phase singularities detected (30.1±7.8–36.6±9.3; mean difference 6.5; 95% CI, 2.6–10.0, P=0.002). The percentage of left atrial surface area with LRA increased with adenosine and 42 of 70 zones (60%) with highest density of LRA coincided with high density LRA zones at baseline with only 28% stable across multiple maps. CONCLUSIONS: Adenosine accelerates atrial fibrillation and promotes rotational activation patterns with no impact on focal activation. There is little evidence that rotational activation seen with adenosine represents promising targets for ablation aimed at sites of stable arrhythmogenic sources in the left atrium
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