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Background: There is a paucity of data comparing vitamin K antagonists (VKAs) to direct oral anticoagulants (DOACs) at the time of cardiac implantable electronic device (CIED) surgery. Furthermore, the best management of DOACs (interruption vs continuation) is yet to be determined., Objectives: This study aimed to compare the incidence of device-related bleeds and thrombotic events based on anticoagulant type (DOAC vs VKA) and regimen (interrupted vs uninterrupted)., Methods: This was an observational multicenter study. We included patients on chronic oral anticoagulation undergoing CIED surgery. Patients were matched using propensity scoring., Results: We included 1,975 patients (age 73.8 ± 12.4 years). Among 1,326 patients on DOAC, this was interrupted presurgery in 78.2% (n = 1,039) and continued in 21.8% (n = 287). There were 649 patients on continued VKA. The matched population included 861 patients. The rate of any major bleeding was higher with continued DOAC (5.2%) compared to interrupted DOAC (1.7%) and continued VKA (2.1%) (P = 0.03). The rate of perioperative thromboembolism was 1.4% with interrupted DOAC, whereas no thromboembolic events occurred with DOAC or VKA continuation (P = 0.04). The use of dual antiplatelet therapy, DOAC continuation, and male sex were independent predictors of major bleeding on a multivariable analysis., Conclusions: In this large real-world cohort, a continued DOAC strategy was associated with a higher bleeding risk compared to DOAC interruption or VKA continuation in patients undergoing CIED surgery. However, DOAC interruption was associated with increased thromboembolic risk. Concomitant dual antiplatelet therapy should be avoided whenever clinically possible. A bespoke approach is necessary, with a strategy of minimal DOAC interruption likely to represent the best compromise., Competing Interests: Funding Support and Author Disclosures Dr Creta has received speaker fees from Boston Scientific. Dr Finlay has received research support and speaker fees from Abbott Ltd, Medtronic Ltd, and Biosense Webster; is Chief Medical Officer, Founder, and Shareholder of Echopoint Medical Ltd; is Director, Founder, and Shareholder of Rhythm AI; is Founder and Shareholder of Epicardio Ltd; and has received research funding from National Institutes of HealthR Barts BRC funding. Dr Lambiase has received educational grants from Medtronic and Boston Scientific; and is supported by UCLH Biomedicine National Institute for Health and Care Research and Barts BRC funding. Dr Schilling has had research agreements and has received speaker fees from Abbott, Medtronic, Boston Scientific, and Biosense Webster; and is a shareholder of AI Rhythm. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Recent studies suggest persistent atrial fibrillation (AF) is maintained by localized focal or rotational electrical activations termed drivers., Objective: The purpose of this study was to evaluate how left atrial (LA) dilation and time in AF impact persistent AF mechanisms., Methods: Patients with persistent AF <2 years underwent electrocardiographic image mapping. Potential drivers (PDs) were defined as rotational wavefront activity ≥1.5 revolutions or focal activations. Distribution of PDs was recorded using an 18-segment model., Results: One hundred patients were enrolled (age 61.3 ± 12.1 years). Of these patients, 47 were hypertensive, 14 had diabetes mellitus, and 10 had ischemic heart disease. AF duration was 8 [5-15] months. Median LA diameter was 39 [33-43] mm. Although LA dimensions did not correlate with overall PD burden or distribution, there was a modest correlation between increasing LA area (r = 0.235; P = .024) and LA volume (r = 0.216; P = .039) with proportion of PDs that were rotational. Although time in AF did not correlate with overall PD burden or distribution, there was a correlation between time in AF and the number of focal PDs (r = 0.203; P = .044). Female gender, increasing age, and hypertension also were associated with an increase in focal PDs., Conclusion: This is the first study to demonstrate different AF mechanisms in patient subgroups. Greater understanding of patient-specific AF mechanisms may facilitate a tailored approach to AF mapping and ablation., (© 2022 Heart Rhythm Society. Published by Elsevier Inc.)

Objectives: This study sought to assess the association between electrocardiographic imaging (ECGI) parameters and voltage from simultaneous electroanatomic mapping (EAM)., Background: ECGI offers noninvasive assessment of electrophysiologic features relevant for mapping ventricular arrhythmia and its substrate, but the accuracy of ECGI in the delineation of scar is unclear., Methods: Sixteen patients with structural heart disease underwent simultaneous ECGI (CardioInsight, Medtronic) and contact EAM (CARTO, Biosense-Webster) during ventricular tachycardia catheter ablation, with 7 mapped epicardially. ECGI and EAM geometries were coregistered using anatomic landmarks. ECGI points were paired to the closest site on the EAM within 10 mm. The association between EAM voltage and ECGI features from reconstructed epicardial unipolar electrograms was assessed by mixed-effects regression models. The classification of low-voltage regions was performed using receiver-operating characteristic analysis., Results: A total of 9,541 ECGI points (median: 596; interquartile range: 377-737 across patients) were paired to an EAM site. Epicardial EAM voltage was associated with ECGI features of signal fractionation and local repolarization dispersion (N = 7; P < 0.05), but they poorly classified sites with bipolar voltage of <1.5 mV or <0.5 mV thresholds (median area under the curve across patients: 0.50-0.62). No association was found between bipolar EAM voltage and low-amplitude reconstructed epicardial unipolar electrograms or ECGI-derived bipolar electrograms. Similar results were found in the combined cohort (n = 16), including endocardial EAM voltage compared to epicardial ECGI features (n = 9)., Conclusions: Despite a statistically significant association between ECGI features and EAM voltage, the accuracy of the delineation of low-voltage zones was modest. This may limit ECGI use for pr-procedural substrate analysis in ventricular tachycardia ablation, but it could provide value in risk assessment for ventricular arrhythmias., Competing Interests: Funding Support and Author Disclosures Dr Graham was supported by a Barts Charity grant. Dr Lambiase was supported by University College London Hospital Biomedicine National Institute for Health Research and Barts Biomedical Research Centre; has received research grants from Boston Scientific, Medtronic, and Abbott; and has received speaker fees from Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: The presence of dynamic substrate changes may facilitate functional block and reentry in ventricular tachycardia (VT)., Objective: We aimed to study dynamic ventricular repolarization changes in critical regions of the VT circuit during sensed single extrastimulus pacing known as the Sense Protocol (SP)., Methods: Twenty patients (aged 67 ± 9 years, 17 male) underwent VT ablation. A bipolar voltage map was obtained during sinus rhythm (SR) and right ventricular SP pacing at 20 ms above ventricular effective refractory period. Ventricular repolarization maps were constructed. Ventricular repolarization time (RT) was calculated from unipolar electrogram T waves, using the Wyatt method, as the dV/dt max of the unipolar T wave. Entrainment or pace mapping confirmed critical sites for ablation., Results: The median global repolarization range (max-min RT per patient) was 166 ms (interquartile range [IQR] 143-181 ms) during SR mapping vs 208 ms (IQR 182-234) during SP mapping ( P = .0003 vs intrinsic rhythm). Regions of late potentials (LP) had a longer RT during SP mapping compared to regions without LP (mean 394 ± 40 ms vs 342 ± 25 ms, P < .001). In paired regions of normal myocardium there was no significant spatial dispersion of repolarization (SDR)/10 mm 2 during SP mapping vs SR mapping (SDR 11 ± 6 ms vs 10 ± 6 ms, P = .54). SDR/10 mm 2 was greater in critical areas of the VT circuit during SP mapping 63 ± 29 ms vs SR mapping 16 ± 9 ms ( P < .001)., Conclusion: Ventricular repolarization is prolonged in regions of LP and increases dynamically, resulting in dynamic SDR in critical areas of the VT circuit. These dynamic substrate changes may be an important factor that facilitates VT circuits., (© 2021 Heart Rhythm Society. Published by Elsevier Inc.)

Objectives: The goal of this study was to develop a risk score model for patients with Brugada syndrome (BrS)., Background: Risk stratification in BrS is a significant challenge due to the low event rates and conflicting evidence., Methods: A multicenter international cohort of patients with BrS and no previous cardiac arrest was used to evaluate the role of 16 proposed clinical or electrocardiogram (ECG) markers in predicting ventricular arrhythmias (VAs)/sudden cardiac death (SCD) during follow-up. Predictive markers were incorporated into a risk score model, and this model was validated by using out-of-sample cross-validation., Results: A total of 1,110 patients with BrS from 16 centers in 8 countries were included (mean age 51.8 ± 13.6 years; 71.8% male). Median follow-up was 5.33 years; 114 patients had VA/SCD (10.3%) with an annual event rate of 1.5%. Of the 16 proposed risk factors, probable arrhythmia-related syncope (hazard ratio [HR]: 3.71; p < 0.001), spontaneous type 1 ECG (HR: 3.80; p < 0.001), early repolarization (HR: 3.42; p < 0.001), and a type 1 Brugada ECG pattern in peripheral leads (HR: 2.33; p < 0.001) were associated with a higher risk of VA/SCD. A risk score model incorporating these factors revealed a sensitivity of 71.2% (95% confidence interval: 61.5% to 84.6%) and a specificity of 80.2% (95% confidence interval: 75.7% to 82.3%) in predicting VA/SCD at 5 years. Calibration plots showed a mean prediction error of 1.2%. The model was effectively validated by using out-of-sample cross-validation according to country., Conclusions: This multicenter study identified 4 risk factors for VA/SCD in a primary prevention BrS population. A risk score model was generated to quantify risk of VA/SCD in BrS and inform implantable cardioverter-defibrillator prescription., Competing Interests: Funding Support and Author Disclosures Dr. Lambiase is supported by the Stephen Lyness Memorial Fund, UCLH Biomedicine National Institutes of Health Research, Barts Biomedical Research Centre; and has obtained research grants and speaker fees from Medtronic, Abbott, and Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: The goal of this study was to evaluate the role of dynamic substrate changes in facilitating conduction delay and re-entry in ventricular tachycardia (VT) circuits., Background: The presence of dynamic substrate changes facilitate functional block and re-entry in VT but are rarely studied as part of clinical VT mapping., Methods: Thirty patients (age 67 ± 9 years; 27 male subjects) underwent ablation. Mapping was performed with the Advisor HD Grid multipolar catheter. A bipolar voltage map was obtained during sinus rhythm (SR) and right ventricular sense protocol (SP) single extra pacing. SR and SP maps of late potentials (LP) and local abnormal ventricular activity (LAVA) were made and compared with critical sites for ablation, defined as sites of best entrainment or pace mapping. Ablation was then performed to critical sites, and LP/LAVA identified by the SP., Results: At a median follow-up of 12 months, 90% of patients were free from antitachycardia pacing (ATP) or implantable cardioverter-defibrillator shocks. SP pacing resulted in a larger area of LP identified for ablation (19.3 mm 2 vs. 6.4 mm 2 ) during SR mapping (p = 0.001), with a sensitivity of 87% and a specificity of 96%, compared with 78% and 65%, respectively, in SR., Conclusions: LP and LAVA observed during the SP were able to identify regions critical for ablation in VT with a greater accuracy than SR mapping. This may improve substrate characterization in VT ablation. The combination of ablation to critical sites and SP-derived LP/LAVA requires further assessment in a randomized comparator study., Competing Interests: Author Disclosures This work was supported by University College London Hospitals Biomedicine National Institute for Health Research. Dr. Srinivasan was supported by a British Heart Foundation Clinical Research Training Fellowship (FS/14/9/30407). Dr. Lambiase was supported by the Medical Research Council (G0901819), Barts BRC, and the Stephen Lyness Research Fund. Drs. Srinivasan, Chow, Lowe, Schilling, and Lambiase have received speaker fees from Abbott in the last 10 years. Dr. Lambiase has received research grants from Boston Scientific and Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to demonstrate that a stochastic vector-based mapping approach could guide ablation of atrial fibrillation (AF) drivers as evidenced by ablation response and long-term follow-up outcomes., Background: The optimal method for mapping and ablation of AF drivers is yet to be defined., Methods: Patients undergoing persistent AF ablation were recruited. Patients underwent pulmonary vein isolation (PVI) with further ablation guided by the stochastic trajectory analysis of ranked signals (STAR) mapping method. The proportion of the time an electrode's activation was seen to precede its neighboring electrodes activation was used to determine early sites of activation (ESA). A positive ablation response at ESA was defined as AF termination or cycle length slowing of ≥30 ms. Clinical outcome was defined as recurrence of AF/atrial tachycardia (AT) during a follow-up of 12 months., Results: Thirty-five patients were included (AF duration of 14.4 ± 5.3 months). After PVI, an average of 2.6 ± 0.8 ESA were ablated per patient with study-defined ablation response achieved in all patients. Of the 86 STAR maps created post-PVI, the same ESA was identified on 73.8 ± 26.1% of maps. ESA that resulted in AF termination were more likely to be identified on both pre- and post-PVI maps than those associated with cycle length slowing (23 of 24 vs. 16 of 49; p < 0.001). During a follow-up of 18.5 ± 3.7 months, 28 (80%) patients were free from AF/AT., Conclusions: The ablation response at ESA suggests they may be drivers of AF. Ablation guided by STAR mapping produced a favorable clinical outcome and warrants testing through a randomized controlled trial. (Identification, Electro-mechanical Characterisation and Ablation of Driver Regions in Persistent Atrial Fibrillation [STAR MAPPING]; NCT02950844)., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to use a novel panoramic mapping system (CARTOFINDER) to detect and characterize drivers in persistent atrial fibrillation (AF)., Background: Mechanisms sustaining persistent AF remain uncertain., Methods: Patients undergoing catheter ablation for persistent AF were included. A 64-pole basket catheter was used to acquire unipolar signals, which were processed by the mapping system to generate wavefront propagation maps. The system was used to identify and characterize potential drivers in AF pre- and post-pulmonary vein (PV) isolation. The effect of ablation on drivers identified post-PV isolation was assessed., Results: Twenty patients were included in the study with 112 CARTOFINDER maps created. Potential drivers were mapped in 19 of 20 patients with AF (damage to the basket and noise on electrograms was present in 1 patient). Thirty potential drivers were identified all of which were transient but repetitive; 19 were rotational and 11 focal. Twenty-six drivers were ablated with a predefined response in 22 of 26 drivers: AF terminated with 12 and cycle length slowed (≥30 ms) with 10. Drivers with rotational activation were predominantly mapped to sites of low-voltage zones (81.8%). PV isolation had no remarkable impact on the cycle length at the driver sites (138.4 ± 14.3 ms pre-PV isolation vs. 137.2 ± 15.2 ms post-PV isolation) and drivers that had also been identified on pre-PV isolation maps were more commonly associated with AF termination., Conclusions: Drivers were identified in almost all patients in the form of intermittent but repetitive focal or rotational activation patterns. The mechanistic importance of these phenomena was confirmed by the response to ablation.

Objectives: This study sought to assess the impact of ablation power and catheter irrigation during clinical radiofrequency ablation using impedance drop., Background: In preclinical studies, ablation power and catheter irrigation are determinants of ablation efficacy., Methods: Static 30-s left atrial ablations were delivered in patients undergoing their first atrial fibrillation ablation. Impedance drop during ablation (as a measure of efficacy) was compared using the following: the force time integral (FTI); the FTI-P (a cumulative multiple FTI and ablation power), and ablation index (AI), a weighted algorithm including contact force, power, and duration. Comparison was also made between a conventionally irrigated (SmartTouch [ST]) versus surround flow (STSF) contact force-sensing catheter., Results: We analyzed 1,013 ablations. For both catheters, the Spearman correlation was higher between impedance drop and AI (rho = 0.89 ST, 0.84 STSF) than FTI-P (rho = 0.71 ST, 0.53 STSF) or FTI (rho = 0.77 ST, 0.52 STSF); p < 0.0005 for each. STSF ablations had lower minimum catheter tip temperatures (25°C [interquartile range (IQR): 25°C to 27°C] vs. 35°C [IQR: 34°C to 36°C]; p < 0.005), and lesser impedance drop per FTI or AI (p < 0.005 for both). For STSF, impedance drop plateaued sooner than for ST with respect to FTI (184g.s vs. 463g.s) and AI (370 AI vs. 430 AI)., Conclusions: AI is a more complete ablation descriptor than is FTI or FTI-P, reflected by a stronger correlation with impedance drop. STSF ablations have lower impedance drop per AI or FTI than ST ablations do, suggesting different targets should be used if ablating guided by impedance drop with STSF. With ST, ablation beyond 430 AI provides minimal additional biophysical efficacy, suggesting an upper limit to use for clinical ablation., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)