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Background: Early rhythm-control after atrial fibrillation (AF) incidence is associated with improved cardiovascular outcomes. Moreover, AF ablation provides more effective rhythm-control than antiarrhythmic drugs (AADs). The extent of adoption of contemporary trials and guidelines for the management of new onset AF is unknown., Objective: In this observational retrospective study, we sought to evaluate treatment pathways for new onset AF at a large tertiary academic medical center within the last 6 years., Methods: We performed a systematic search within our institutional TriNetX database to identify adult patients who (1) had new onset AF between January 2018 and January 2023, (2) did not have surgery or thyrotoxicosis within 1 month of incident AF diagnosis, and (3) had at least one visit at our center > 6 months after initial AF diagnosis. Patients with prior AF diagnosis were excluded. We identified the initial three lines of treatment administered following AF diagnosis, including rate- or rhythm-control strategies with AADs or ablation therapy., Results: The cohort included 24 990 patients (mean age at diagnosis 69.8 ± 13.1 years, 58% male). During follow-up, 7130 (29%) received rhythm-control, 9760 (39%) received rate-control, and 8100 (32%) received neither. Rhythm-control consisted of AADs in 4610 (18%) and AF ablation in 2530 (10%). As first line therapy, 12 055 (48%) patients received rate-control, 3919 (16%) received AADs and 916 (4%) underwent AF ablation., Conclusion: Most contemporary patients with incident AF at a large US academic tertiary center either received no rate or rhythm intervention or only rate-control., (© 2025 Wiley Periodicals LLC.)

Importance: Noninvasive localization of the compact atrioventricular node and the proximal specialized conduction system (AVCS) would enhance planning for transcatheter aortic valve and complex or congenital heart disease surgical procedures., Objective: To test the hypothesis that preprocedure contrast-enhanced cardiac computed tomography (CECT) can accurately localize the AVCS by identification of the fat that insulates the conductive myocardium., Design, Setting, and Participants: This was a prospective cohort study that took place at an academic tertiary care center. Included in the study were patients with CECT acquired less than 1 month before atrial fibrillation ablation and electroanatomic localization of the His electrogram signal on electroanatomic mapping (EAM) between January 2022 and January 2023., Exposures: Preprocedure CECT., Main Outcomes and Measures: The distance from the His electrogram signal to the fat segmentation encompassing the AVCS on CECT, after registration of the images to EAM., Results: Among 20 patients (mean [SD] age, 66 [10] years; 15 male [75%]) in the cohort, the mean (SD) attenuation of the AVCS fat segmentation was 2.9 (21.5) Hounsfield units. The mean (SD) distance from the His electrogram to the closest AVCS fat voxel was 3.3 (1.6) mm., Conclusions and Relevance: Results of this cohort study suggest that CECT could accurately localize the fatty tissue that insulates the AVCS from surrounding atrial and ventricular myocardium and may enhance the efficacy and safety of procedures targeting the conduction system and structures in its proximity.

Competing Interests: Funding Support and Author Disclosures Dr Nazarian is funded by the National Institute of Health grant R01HL142893. Dr Xu is funded by American Heart Association grant 23POST909139. Dr Nazarian receives research funding from Biosense Webster and ADAS software. Dr Marchlinski has served as consultant for Abbott Medical, Biosense Webster, Biotronik, and Medtronic Inc. The University of Pennsylvania Conflict of Interest Committee manages all commercial arrangements. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Competing Interests: Competing interests: SN is a consultant for CardioSolv and Circle CVI; and principal investigator for research funding from Biosense Webster, ImriCor, Siemens, ADAS software and the US NIH. The University of Pennsylvania Conflict of Interest Committee manages all commercial arrangements. TZ has nothing to disclose.

Purpose: To determine the prevalence and correlates of left atrial (LA) late gadolinium enhancement (LGE) at cardiac MRI and its association with atrial fibrillation (AF) in a population-based sample from the Multi-Ethnic Study of Atherosclerosis (MESA)., Materials and Methods: In this secondary post hoc analysis of the MESA cohort (ClinicalTrials.gov no. NCT00005487), participants without AF underwent LGE cardiac MRI at the fifth examination (2010-2012). LA LGE burden was quantified using the image intensity ratio technique on biplane long-axis two-dimensional (2D) LGE images without fat saturation. Survival analysis was performed with log-rank testing and Cox regression., Results: Of 1697 participants (mean age, 67 years ± 9 [SD]; 872 men), 1035 (61%) had LA LGE, and 75 (4.4%) developed AF during follow-up (median, 3.95 years). At univariable analysis, LA LGE was associated with age (β = .010 [95% CI: .005, .015], P < .001), diastolic blood pressure (β = .005 [95% CI: .001, .009], P = .02), HbA1c level (β = .06 [95% CI: .02, .11], P = .009), heart failure (β = .60 [95% CI: .11, 1.08], P = .02), LA volume (β = .008 [95% CI: .004, .012], P < .001), and LA function (emptying fraction, LA global longitudinal strain, LA early diastolic peak longitudinal strain rate, and LA late diastolic peak strain rate; all P < .05). After adjusting for the variables in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) AF score, LA LGE independently helped predict incident AF (hazard ratio = 1.46 [95% CI: 1.13, 1.88], P = .003). The highest tertile (LGE > 2%) was twice as likely to develop AF., Conclusion: Although limited by the 2D LGE technique employed, LA LGE was associated with adverse atrial remodeling and helped predict AF in a multiethnic population-based sample.Clinical trial registration no. NCT00005487 Keywords: MR Imaging, Cardiac, Epidemiology Supplemental material is available for this article. © RSNA, 2023., Competing Interests: Disclosures of conflicts of interest: T.Z. No relevant relationships. T.Q.A.C.S. No relevant relationships. B.A.V. No relevant relationships. E.X. No relevant relationships. M.R.O. No relevant relationships. M.H. No relevant relationships. D.A.B. Editor emeritus for Radiology. E.Z.S. No relevant relationships. C.O.W. No relevant relationships. S.R.H. Support for the present article from the National Institutes of Health (NIH), paid to author's institution. S.N. Research funding from Biosense Webster, Imricor, Siemens, ADAS software, and the NIH; consulting fees from CardioSolv and Circle CVI; payment for lectures from Circle CVI. J.A.C.L. NIH grant support., (© 2023 by the Radiological Society of North America, Inc.)

Introduction: Pericardial bleeding is a rare but life-threatening complication of atrial fibrillation (AF) ablation. Patients taking uninterrupted oral anticoagulation (AC) may be at increased risk for refractory bleeding despite pericardiocentesis and administration of protamine. In such cases, andexanet alfa can be given to reverse rivaroxaban or apixaban. In this study, we aim to describe the rate of acute hemostasis and thromboembolic complications with andexanet for refractory pericardial bleeding during AF ablation., Methods and Results: In this multicenter, case series, participating centers identified patients who received a dose of apixaban or rivaroxaban within 24 h of AF ablation, developed refractory pericardial bleeding during the procedure despite pericardiocentesis and administration of protamine and received andexanet. Eleven patients met inclusion criteria, with mean age of 73.5 ± 5.3 years and median CHA 2 DS 2 -VASc score 4 [3-5]. All patients received protamine and pericardiocentesis, and 9 (82%) received blood products. All patients received a bolus of andexanet followed, in all but one, by a 2-h infusion. Acute hemostasis was achieved in eight patients (73%) while three required emergent surgery. One patient (9%) experienced acute ST-elevation myocardial infarction after receiving andexanet. Therapeutic AC was restarted after a mean of 2.2 ± 1.9 days and oral AC was restarted after a mean of 2.9 ± 1.6 days, with no recurrent bleeding., Conclusion: In patients on uninterrupted apixaban or rivaroxaban, who develop refractory pericardial bleeding during AF ablation, andexanet can achieve hemostasis thereby avoiding the need for emergent surgery. However, there is a risk of thromboembolism following administration., (© 2023 Wiley Periodicals LLC.)

Background: Despite luminal esophageal temperature (LET) monitoring, esophageal injury remains a risk which impacts decision making during atrial fibrillation (AF) ablation. We sought to compare procedural characteristics including radiofrequency (RF) power, duration, and LET, among ablation procedures with and without image segmentation for esophageal visualization (EV)., Methods: The retrospective cohort included 73 patients (mean age 65.2 ± 8.6 years, 36% female, 55% paroxysmal AF) who underwent pre-procedural cardiac magnetic resonance or computed tomography and LET monitoring. Of all patients, 35 were historical patients that underwent standard AF ablation without EV, and 38 were contemporary patients, 28 of whom underwent AF ablation with EV and 10 that underwent AF ablation without EV., Results: Total RF time was similar between the groups. The distribution of ablation power delivery was skewed toward higher power in the contemporary patients. However, among patients in the contemporary group, the proportion of > 35 Watts lesions was lower with EV (P < 0.001). There was no difference between the max or mean LET. The standard deviation of LET change within patient during posterior wall ablation was lower in those with esophageal visualization compared to historical controls, but no change was seen compared to a smaller group of contemporary controls. No long-term clinical esophageal injury was observed., Conclusions: In a retrospective analysis, EV was successfully performed in 28 patients. EV impacted RF power delivery decisions but was unassociated with RF time, changes in LET, or long-term safety., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Right ventricular (RV) dysfunction and late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) are associated with ventricular arrhythmias (VA) and mortality in cardiac sarcoidosis (CS). However, image resolution limits the detection of RV LGE. Global longitudinal RV strain (RVS) correlates to RV scar on electroanatomical mapping and RV function., Objective: We evaluated the association between RVS on CMR and VA/death (combined-primary-endpoint (CPE)) in patients with CS., Methods: RVS and RV LGE on MRI were retrospectively compared to variables known to predict outcomes in 66 patients with CS. Outcomes were obtained from electronic medical records and implantable cardioverter defibrillator (ICD) interrogations over median [IQR] 3.7[1.7, 6.3] years. Cox proportional hazard models were used to evaluate survival. Harrell's C-statistic was used to compare variables in risk prediction models., Results: 62.1 % of patients were male, with a mean age [SD] of 52.3 [9.6] years and left ventricular ejection fraction (LVEF) of 51.1[17.5]%. 9 patients with the primary endpoint were more likely to be Caucasian (p = 0.01) with prior VAs (p = 0.002), be on anti-arrhythmic drugs (p = 0.001) with an ICD (p = 0.002). In multivariable analyses adjusted for age, race, and history of VA, RVS (1.18 [1.05-1.31], p = 0.004), RV EDVI (1.08[1.01, 1.14], p = 0.02), and LV LGE (1.07[1.00, 1.13], p = 0.04) predicted the CPE. Risk prediction models including RVS (Cstatistic 0.94), outperformed those including RV and LV LGE (0.89-0.92)., Conclusion: RVS on CMR was the best predictor of VA and mortality in CS., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)

Importance: Autonomic neuromodulation provides therapeutic benefit in ventricular tachycardia (VT) storm. Transcutaneous magnetic stimulation (TcMS) can noninvasively and nondestructively modulate a patient's nervous system activity and may reduce VT burden in patients with VT storm., Objective: To evaluate the safety and efficacy of TcMS of the left stellate ganglion for patients with VT storm., Design, Setting, and Participants: This double-blind, sham-controlled randomized clinical trial took place at a single tertiary referral center between August 2019 and July 2021. The study included 26 adult patients with 3 or more episodes of VT in 24 hours., Interventions: Patients were randomly assigned to receive a single session of either TcMS that targeted the left stellate ganglion (n = 14) or sham stimulation (n = 12)., Main Outcomes and Measures: The primary outcome was freedom from VT in the 24-hour period following randomization. Key secondary outcomes included safety of TcMS on cardiac implantable electronic devices, as well as burden of VT in the 72-hour period following randomization., Results: Among 26 patients (mean [SD] age, 64 [13] years; 20 [77%] male), a mean (SD) of 12.7 (10.3) episodes of VT occurred within the 24 hours preceding randomization. Patients had recurrent VT despite taking a mean (SD) of 2.0 (0.6) antiarrhythmic drugs (AADs), and 11 patients (42%) required mechanical hemodynamic support at the time of randomization. In the 24-hour period after randomization, VT recurred in 4 of 14 patients (29% [SD 47%]) in the TcMS group vs 7 of 12 patients (58% [SD 51%]) in the sham group (P = .20). In the 72-hour period after randomization, patients in the TcMS group had a mean (SD) of 4.5 (7.2) episodes of VT vs 10.7 (13.8) in the sham group (incidence rate ratio, 0.42; P < .001). Patients in the TcMS group were taking fewer AADs 24 hours after randomization compared with baseline (mean [SD], 0.9 [0.8] vs 1.8 [0.4]; P = .001), whereas there was no difference in the number of AADs taken for the sham group (mean [SD], 2.3 [0.8] vs 1.9 [0.5]; P = .20). None of the 7 patients in the TcMS group with a cardiac implantable electronic device had clinically significant effects on device function., Conclusions and Relevance: In this randomized clinical trial, findings support the potential for TcMS to safely reduce the burden of VT in the setting of VT storm in patients with and without cardiac implantable electronic devices and inform the design of future trials to further investigate this novel treatment approach., Trial Registration: ClinicalTrials.gov Identifier: NCT04043312.

Introduction: Esophageal injury during atrial fibrillation (AF) ablation is a life-threatening complication. We sought to measure the association of esophageal temperature attenuation with radiofrequency (RF) electrode impedance, contact force, and distance from the esophagus., Methods: The retrospective study cohort included 35 patients with mean age 64 ± 10 years, of whom 74.3% were male, and 40% had persistent AF. All patients had undergone preprocedural cardiac magnetic resonance (CMR) followed by AF ablation with luminal esophageal temperature monitoring. Lesion locations were co-registered with CMR image segmentations of left atrial and esophageal anatomy. Luminal esophageal temperature, time matched RF lesion data, and ablation distance from the nearest esophageal location were collected as panel data., Results: Luminal esophageal temperature changes corresponding to 3667 distinct lesions, delivered with mean power 27.9 ± 5.5 W over a mean duration of 22.2 ± 10.5 s were analyzed. In multivariable analyses, clustered per patient, examining posterior wall lesions only, and adjusted for lesion power and duration as set by the operator, lesion distance from the esophagus (-0.003°C/mm, p < .001), and baseline impedance (-0.015°C/Ω, p < .001) were associated with changes in luminal esophageal temperature., Conclusion: Esophageal luminal temperature rises are associated with shorter lesion distance from esophagus and lower baseline impedance during RF lesion delivery. When procedural strategy requires RF delivery near the esophagus, selection of sites with higher baseline impedance may improve safety., (© 2021 Wiley Periodicals LLC.)

Background: Left ventricular (LV) fibrofatty infiltration in arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C) has been reported, however, detailed cardiovascular magnetic resonance (CMR) characteristics and association with outcomes are uncertain. We aim to describe LV findings on CMR in ARVD/C patients and their relationship with arrhythmic outcomes., Methods: CMR of 73 subjects with ARVD/C according to the 2010 Task Force Criteria (TFC) were analyzed for LV involvement, defined as ≥ 1 of the following features: LV wall motion abnormality, LV late gadolinium enhancement (LGE), LV fat infiltration, or LV ejection fraction (LVEF) < 50%. Ventricular volumes and function, regional wall motion abnormalities, and the presence of ventricular fat or fibrosis were recorded. Findings on CMR were correlated with arrhythmic outcomes., Results: Of the 73 subjects, 50.7% had CMR evidence for LV involvement. Proband status and advanced RV dysfunction were independently associated with LV abnormalities. The most common pattern of LV involvement was focal fatty infiltration in the sub-epicardium of the apicolateral LV with a "bite-like" pattern. LGE in the LV was found in the same distribution and most often had a linear appearance. LV involvement was more common with non-PKP2 genetic mutation variants, regardless of proband status. Only RV structural disease on CMR (HR 3.47, 95% CI 1.13-10.70) and prior arrhythmia (HR 2.85, 95% CI 1.33-6.10) were independently associated with arrhythmic events., Conclusion: Among patients with 2010 TFC for ARVD/C, CMR evidence for LV abnormalities are seen in half of patients and typically manifest as fibrofatty infiltration in the subepicardium of the apicolateral wall and are not associated with arrhythmic outcomes.

Background: Typical atrial flutter (AFL) often occurs in patients with atrial fibrillation (AF). Decision-making tools for application of prophylactic cavo-tricuspid isthmus (CTI) ablation at the time of AF ablation may improve outcomes. In this study, we sought to define the right atrial (RA) functional characteristics of AF patients with documented typical AFL., Methods: Consecutive patients that underwent cardiac magnetic resonance (CMR) prior to initial AF ablation in the Johns Hopkins Hospital were enrolled. The AF database was reviewed to identify prevalent and incident documented typical AFL. Feature tracking CMR analysis during sinus rhythm was utilized to quantify RA longitudinal strain and strain rate, as well as RA passive and active emptying fractions derived from phasic RA volumes., Results: A total of 115 patients were analyzed (mean age 59.1 ± 11.4 years, 78.3% male, 74.8% paroxysmal AF). Of all patients, 30 (26.1%) had typical AFL. Clinical characteristics and AF type did not differ among groups defined by the absence or presence of typical AFL. In contrast, RA longitudinal strain (41.6 ± 16.8% vs. 55.8 ± 17.1%, p ≤ 0.001), systolic strain rate (1.71 ± 0.85 s -1 vs. 2.33 ± 0.93 s -1 , p = 0.002), and late diastolic strain rate (1.78 ± 1.02 s -1 vs. 2.50 ± 0.91 s -1 p ≤ 0.001) were significantly lower in patients with typical AFL. Although RA passive emptying fraction was similar among groups (18.9 ± 8.1 vs. 19.5 ± 8.0, p = 0.75), RA active emptying fraction was lower in patients with typical AFL (34.8 ± 12.3 vs. 40.8 ± 12.1, p = 0.02)., Conclusions: The reservoir and pump function of the RA is significantly reduced in patients with typical AFL. Prophylactic CTI ablation warrants further study as adjunctive therapy to AF catheter ablation in selected patients with RA dysfunction.

Introduction: The association of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) with epicardial and surface ventricular tachycardia (VT) electrogram features, in nonischemic cardiomyopathy (NICM), is unknown. We sought to define the association of LGE and viable wall thickness with epicardial electrogram features and exit site paced QRS duration in patients with NICM., Methods: A total of 19 patients (age 53.5 ± 11.5 years) with NICM (ejection fraction 40.2 ± 13.2%) underwent CMR before VT ablation. LGE transmurality was quantified on CMR and coregistered with 2294 endocardial and 2724 epicardial map points., Results: Both bipolar and unipolar voltage were associated with transmural signal intensity on CMR. Longer electrogram duration and fractionated potentials were associated with increased LGE transmurality, but late potentials or local abnormal ventricular activity were more prevalent in nontransmural versus transmural LGE regions (p < .05). Of all critical VT sites, 19% were located adjacent to regions with LGE but normal bipolar and unipolar voltage. Exit site QRS duration was affected by LGE transmurality and intramural scar location, but not by wall thickness, at the impulse origin., Conclusions: In patients with NICM and VT, LGE is associated with epicardial electrogram features and may predict critical VT sites. Additionally, exit site QRS duration is affected by LGE transmurality and intramural location at the impulse origin or exit., (© 2020 Wiley Periodicals LLC.)

Introduction: Advanced interatrial block (IAB) on a 12-lead electrocardiogram (ECG) is a predictor of stroke, incident atrial fibrillation (AF), and AF recurrence after catheter ablation. The objective of this study was to determine which features of IAB structural remodeling is associated with left atrium (LA) magnetic resonance imaging structure and function., Methods/results: We included 152 consecutive patients (23% nonparoxysmal AF) who underwent preprocedural ECG and cardiac magnetic resonance (CMR) in sinus rhythm before catheter ablation of AF. IAB was defined as P-wave duration ≥120 ms, and was considered partial if P-wave was positive and advanced if P-wave had a biphasic morphology in inferior leads. From cine CMR and late gadolinium enhancement, we derived LA maximum and minimum volume indices, strain, LA fibrosis, and LA dyssynchrony. A total of 77 patients (50.7% paroxysmal) had normal P-wave, 52 (34.2%) partial IAB, and 23 (15.1%) advanced IAB. Patients with advanced IAB had significantly higher LA minimum volume index (25.7 vs 19.9 mL/m 2 , P = .010), more LA fibrosis (21.9% vs 13.1%, P = .020), and lower LA maximum strain rate (0.99 vs 1.18, P = .007) than those without. Advanced IAB was independently associated with LA (minimum [P = .032] and fibrosis [P = .009]). P-wave duration was also independently associated with LA fibrosis (β = .33; P = .049) and LA mechanical dyssynchrony (β = 2.01; P = .007)., Conclusion: Advanced IAB is associated with larger LA volumes, lower emptying fraction, and more fibrosis. Longer P-wave duration is also associated with more LA fibrosis and higher LA mechanical dyssynchrony., (© 2020 Wiley Periodicals LLC.)

Atrial fibrillation (AF)-the most common arrhythmia-significantly increases the risk of stroke and heart failure. Although catheter ablation can restore normal heart rhythms, patients with persistent AF who develop atrial fibrosis often undergo multiple failed ablations, and thus increased procedural risks. Here, we present personalized computational modelling for the reliable predetermination of ablation targets, which are then used to guide the ablation procedure in patients with persistent AF and atrial fibrosis. First, we show that a computational model of the atria of patients identifies fibrotic tissue that, if ablated, will not sustain AF. Then, we report the results of integrating the target ablation sites in a clinical mapping system and testing its feasibility in ten patients with persistent AF. The computational prediction of ablation targets avoids lengthy electrical mapping and could improve the accuracy and efficacy of targeted AF ablation in patients while eliminating the need for repeat procedures.

Aims: Longitudinal change in left atrial (LA) structure and function could be helpful in predicting risk for incident atrial fibrillation (AF). We used cardiac magnetic resonance (CMR) imaging to explore the relationship between change in LA structure and function and incident AF in a multi-ethnic population free of clinical cardiovascular disease at baseline., Methods and Results: In the Multi-Ethnic Study of Atherosclerosis (MESA), 2338 participants, free at baseline of clinically recognized AF and cardiovascular disease, had LA volume and function assessed with CMR imaging, at baseline (2000-02), and at Exam 4 (2005-07) or 5 (2010-12). Free of AF, 124 participants developed AF over 3.8 ± 0.9 years (2015) following the second imaging. In adjusted Cox regression models, an average annualized change in all LA parameters were significantly associated with an increased risk of AF. An annual decrease of 1-SD unit in total LA emptying fractions (LAEF) was most strongly associated with risk of AF after adjusting for clinical risk factors for AF, baseline LA parameters, and left ventricular mass-to-volume ratio (hazard ratio per SD = 1.91, 95% confidence interval = 1.53-2.38, P < 0.001). The addition of change in total LAEF to an AF risk score improved model discrimination and reclassification (net reclassification improvement = 0.107, P = 0.017; integrative discrimination index = 0.049, P < 0.001)., Conclusion: In this multi-ethnic study population free of clinical cardiovascular disease at baseline, a greater increase in LA volumes and decrease in LA function were associated with incident AF. The addition of change in total LAEF to risk prediction models for AF improved model discrimination and reclassification of AF risk., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Objectives: This study hypothesized that paroxysmal atrial fibrillation (PAF) reflects the presence of a more severe cardiac hypertrophic cardiomyopathy (HCM) phenotype., Background: HCM is characterized by myocyte hypertrophy, fibrosis, and a high prevalence of PAF. It is currently unresolved whether atrial fibrillation (AF) is a marker or a mediator of adverse outcomes in HCM., Methods: This study retrospectively examined 45 HCM patients who underwent cardiovascular magnetic resonance (CMR) imaging in sinus rhythm. The function of all 4 cardiac chambers was assessed, as well as late gadolinium enhancement (LGE) in the left atrium (LA) and left ventricle (LV), as indicators of fibrosis. A fat-saturated, 3-dimensional inversion recovery-prepared, fast-spoiled, gradient-recalled echo sequence, and the image intensity ratio method were used to measure LA-LGE; LGE in the LV was quantified using a semi-automated threshold technique., Results: HCM patients (n = 45) were divided into 2 groups (PAF, no AF) based on history of PAF. All HCM patients had LGE in the LA posterior wall. The PAF group (n = 18) had higher LA volume, a lower LA ejection fraction, a lower global peak longitudinal LA strain (PLAS), and a higher amount of LA-LGE compared with the no AF group (n = 27). A modest inverse association was noted between the LA ejection fraction, PLAS, and LA-LGE; a positive association was present between LV-LGE and LA-LGE. The PAF group had lower ejection fractions in the LV, right atrium, and right ventricle compared with those in the no AF group., Conclusions: PAF is associated with a greater degree of structural LA remodeling and global myopathy, which suggests a more severe cardiac HCM phenotype., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to evaluate the usefulness of intra-atrial dyssynchrony as a marker of underlying left atrial (LA) remodeling to predict recurrence after the first atrial fibrillation (AF) ablation., Background: Catheter ablation for AF remains far from curative with relatively high recurrence rates. One of the causes of recurrence is poor patient selection out of a diverse patient population with different degrees of LA remodeling., Methods: We included 208 patients with a history of AF (59.4 ± 10.0 years of age; 26.0% nonparoxysmal AF) referred for catheter ablation of AF who underwent pre-ablation cardiac magnetic resonance in sinus rhythm. Clinical follow-up was 20 ± 6 months. Using tissue tracking cardiac magnetic resonance, we measured the LA longitudinal strain in each of 12 equal-length segments in 2- and 4-chamber views. We defined intra-atrial dyssynchrony as the standard deviation of the time to the peak longitudinal strain corrected by the cycle length (SD-time to peak strain [TPS], %)., Results: Patients with AF recurrence after ablation (n = 101) had significantly higher SD-TPS than those without (n = 107; 3.9% vs. 2.2%; p < 0.001). Multivariable cox analysis showed that SD-TPS was associated with recurrence after adjusting for clinical risk factors, AF type, LA structure and function, and fibrosis (p < 0.001). Furthermore, receiver-operating characteristics analysis showed SD-TPS improved prediction of recurrence better than clinical risk factors, LA structure and function, and fibrosis., Conclusions: Intra-atrial dyssynchrony during sinus rhythm is an independent predictor of recurrence after the first catheter ablation of paroxysmal or persistent AF. Assessment of intra-atrial dyssynchrony may improve ablation outcomes by refining patient selection., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Recent advances in cardiac magnetic resonance (CMR) imaging acquisition techniques have enabled the visualization of thin atrial myocardium with high temporal and spatial resolution and have the potential to shift atrial fibrillation (AF) management paradigms. Late gadolinium-enhancement (LGE)-CMR can noninvasively identify atrial arrhythmogenic scar substrates and has been shown to spatially correlate with low-voltage areas. Immediately after ablation, a combination of native T1-weighted, LGE, and T2-weighted imaging can assess ablation lesions and localize reversible edema, whereas late after ablation, LGE-CMR can visualize irreversible fibrosis and detect large ablation gaps. Tissue tracking on cine-CMR can be used to characterize the impact of ablation and AF-related remodelling on atrial structure and contractile function. Increased burden of "native" LGE and lower left atrial function at baseline are associated with worse procedural outcomes, and identification of patients with the greatest fibrotic extent may improve patient selection for AF ablation procedures or identify a subset of patients for whom pulmonary vein isolation alone is unlikely to be beneficial. Left atrial appendage morphology and left atrial sphericity index may provide additional prognostic information in AF ablations. A suggested approach for patients with extensive fibrosis includes substrate modification in addition to pulmonary vein isolation. Another approach involves virtual electrophysiological simulation of AF, localization of computationally derived AF drivers, and determination of optimal ablation targets for persistent AF suppression. Finally, both LGE-CMR and cine-CMR have offered invaluable insights into AF-related stroke mechanisms and may enhance available prediction models that guide anticoagulation therapy., (Copyright © 2018 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Bolus timing is critical to optimal magnetic resonance angiography (MRA) acquisitions but can be challenging in some patients. Our purpose was to evaluate whether contrast-enhanced time-resolved magnetic resonance angiography (TR-MRA), a dynamic multiphase sequence that does not rely on bolus timing, is a viable alternative method to conventional 3D fast-long angle shot contrast-enhanced magnetic resonance angiography (CE-MRA). Coronal subtracted conventional CE-MRA images in 50 consecutive patients presenting for pre-atrial fibrillation ablation pulmonary venous (PV) mapping were compared with 50 TR-MRA images performed in 50 subsequent patients. The TR-MRA protocol was modified to optimize spatial resolution with slightly reduced temporal resolution (6.1 s scan time). Three experienced readers evaluated each scan's image quality and relative left atrial (LA) opacification based on a 4-point scale and diagnostic PV visualization in a binary fashion. Additionally, LA signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and PV dimensions were measured for both techniques. TR-MRA had significantly higher overall image quality (3.10 ± 0.69 vs. 2.42 ± 0.69, p < 0.0001), and LA opacification scores (3.33 ± 0.70 vs. 2.15 ± 1.13, p < 0.0001) compared to CE-MRA. The proportion of diagnostically visualized pulmonary veins was 137/150 (91%) in the CE-MRA group vs. 147/150 (98%) with TR-MRA (p = 0.010). Both SNR and CNR were higher with TR-MRA vs. CE-MRA (277.9 ± 48.9 vs. 106.8 ± 41, p = 0.002 and 100.3 ± 41.7 vs. 70.7 ± 48.0, p = 0.002, respectively). Inter-reader variance of individual PV measurements for each of the MR techniques ranged between 0.62 and 1.47 mm and the ICC for vein measurements was higher with TR-MRA (range: 0.62-0.81) compared to CE-MRA (range: 0.47-0.64). TR-MRA, modified to maximize spatial resolution, offers an alternative method for performing high quality MRA examinations in patients with AF. TR-MRA offers greater overall image quality, PV visualization, and similarly reproducible PV measurements compared to traditional CE-MRA, without the challenges of proper bolus timing.

Background: Arrhythmogenic right ventricular cardiomyopathy is an inherited cardiomyopathy characterized by fibrofatty replacement of right ventricular myocardium resulting in reentrant ventricular tachycardia (VT). Cardiac magnetic resonance imaging (CMR) can noninvasively measure regional abnormalities using tissue-tracking strain as well as late gadolinium enhancement (LGE). In this study, we examine arrhythmogenic substrate using regional CMR strain, LGE, and electroanatomic mapping (EAM) in arrhythmogenic right ventricular cardiomyopathy patients presenting for VT ablation., Methods and Results: Twenty-one patients underwent right ventricular endocardial EAM, whereas 17 underwent epicardial EAM, to detect dense scar (<0.5 mV) as well as CMR study within 12 months. Quantitative regional strain analysis was performed in all 21 patients, although the presence of LGE was visually examined in 17 patients. Strain was lower in segments with dense scar on endocardial and epicardial EAM (-9.7±4.1 versus -7.3±4.0, and -9.8±2.8 versus -7.6±3.8; P<0.05), in segments with LGE scar (-9.9±4.4 versus -6.0±3.6; P=0.001), and at VT culprit sites (-7.4±3.7 versus -10.1±4.1; P<0.001), compared with the rest of right ventricular. On patient-clustered analysis, a unit increase in strain was associated with 21% and 18% decreased odds of scar on endocardial and epicardial EAM, respectively, 17% decreased odds of colocalizing VT culprit site, and 43% decreased odds of scar on LGE-CMR ( P<0.05 for all). LGE and EAM demonstrated poor agreement with κ=0.18 (endocardial, n=17) and κ=0.06 (epicardial, n=13). Only 8 (15%) VT termination sites exhibited LGE., Conclusions: Regional myocardial strain on cine CMR improves detection of arrhythmogenic VT substrate compared with LGE. This may enhance diagnostic accuracy of CMR in arrhythmogenic right ventricular cardiomyopathy without the need for invasive procedures and facilitate the planning of VT ablation procedures.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy that is predominantly known to affect the ventricles. Evidence for atrial involvement remains limited. Therefore, we aimed to characterize atrial involvement in ARVC using functional cardiac magnetic resonance, define the extent of atrial size and function variation attributable to ventricular variables, and identify cardiac magnetic resonance-based predictors of atrial arrhythmias (AA) in ARVC., Methods and Results: We analyzed cine cardiac magnetic resonance images of 66 definite ARVC patients without a history of AA or severe heart failure and 24 healthy controls. Using tissue tracking, we evaluated phasic biatrial volumes, ejection fractions (EFs), peak longitudinal strain, and strain rates (SRs). The primary outcome was the occurrence of AA during 6.8 years [3.0-10.8 years] of follow-up. Compared with controls, ARVC patients had higher biatrial volumes, reduced right atrial (RA) conduit function (passive EF [RAEF passive ] and peak early-diastolic SR), reduced RA and left atrial (LA) reservoir function (peak systolic SR), and reduced RA and LA pump function (peak late-diastolic SR; P<0.05). Using multivariable analysis, predictors of increased risk of AA during follow-up were higher atrial volumes (RAV min and LAV min ), decreased LA reservoir function (total LAEF and LA peak longitudinal strain), and decreased RA conduit function (passive RAEF and RA early-diastolic SR)., Conclusions: Compared with controls, patients with ARVC were found to have enlarged atria with decreased function on functional cardiac magnetic resonance examination. RA and LA parameters predict incident AA after adjusting for clinical and ventricular characteristics which suggests atrial involvement in ARVC.

Background: Acute pulmonary vein (PV) reconnection predicts atrial fibrillation (AF) recurrence after ablation. Contact-force (CF) sensing catheters improve lesion delivery. We assessed the incidence, timing, location, and lesion characteristics of acute reconnection after PV isolation with CF sensing catheters., Methods: Patients undergoing radiofrequency ablation for AF from October 2016 to February 2017 were studied. Assessment for acute reconnection at 20 and 40 minute intervals was performed in each isolated PV. Additional lesions were applied as needed. Lesion location, contact force, power, duration, impedance, and force-time integral values were compared at sites with and without reconnection., Results: Twenty-two patients (60.6 + 1.8 years; 36.4% female; 27.3% persistent AF; CHA2DS2VASC 1.9 + 0.3) were included. Eighty-eight veins were isolated. Eleven reconnections occurred in 10 patients; 9 occurred by 20 minutes and 2 between 20 - 40 minutes. Most reconnections (6/11) were in the left superior PV. Of 4993 ablation points analyzed, 72 were at acute reconnection sites, and no differences in average contact force (11.4 + 8.1 vs 11.3 + 7.1 gm, p=0.868), power (29.7 + 3.9 vs 29.9 + 4.6 watts, p=0.620), impedance (64.1 + 60 vs 72.5 + 60, p=0.236) and the force time integral (86.9 + 78.8 vs 99.7 + 100 gm/sec, p=0.282) were found., Conclusion: Acute PV reconnection rates using CF sensing catheters are roughly 12.5%, with the majority occurring within 20 minutes. We found no significant differences in characteristics of ablation points in areas of reconnection. Optimum wait periods after isolation to check for acute reconnection may be as brief as 20 minutes.

Focal impulse and rotor mapping (FIRM) involves intracardiac detection and catheter ablation of re-entrant drivers (RDs), some of which may contribute to arrhythmia perpetuation in persistent atrial fibrillation (PsAF). Patient-specific computational models derived from late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) has the potential to non-invasively identify all areas of the fibrotic substrate where RDs could potentially be sustained, including locations where RDs may not manifest during mapped AF episodes. The objective of this study was to carry out multi-modal assessment of the arrhythmogenic propensity of the fibrotic substrate in PsAF patients by comparing locations of RD-harboring regions found in simulations and detected by FIRM (RD sim and RD FIRM ) and analyze implications for ablation strategies predicated on targeting RDs. For 11 PsAF patients who underwent pre-procedure LGE-MRI and FIRM-guided ablation, we retrospectively simulated AF in individualized atrial models, with geometry and fibrosis distribution reconstructed from pre-ablation LGE-MRI scans, and identified RD sim sites. Regions harboring RD sim and RD FIRM were compared. RD sim were found in 38 atrial regions (median [inter-quartile range (IQR)] = 4 [3; 4] per model). RD FIRM were identified and subsequently ablated in 24 atrial regions (2 [1; 3] per patient), which was significantly fewer than the number of RD sim -harboring regions in corresponding models ( p < 0.05). Computational modeling predicted RD sim in 20 of 24 (83%) atrial regions identified as RD FIRM -harboring during clinical mapping. In a large number of cases, we uncovered RD sim -harboring regions in which RD FIRM were never observed (18/22 regions that differed between the two modalities; 82%); we termed such cases "latent" RD sim sites. During follow-up (230 [180; 326] days), AF recurrence occurred in 7/11 (64%) individuals. Interestingly, latent RD sim sites were observed in all seven computational models corresponding to patients who experienced recurrent AF (2 [2; 2] per patient); in contrast, latent RD sim sites were only discovered in two of four patients who were free from AF during follow-up (0.5 [0; 1.5] per patient; p < 0.05 vs. patients with AF recurrence). We conclude that substrate-based ablation based on computational modeling could improve outcomes.

Background: Ablation-induced left atrial (LA) edema may result in procedural failure due to reversible pulmonary vein isolation. Conventional T2-weighted magnetic resonance edema imaging is limited by low spatial resolution., Objective: The purpose of this pilot study was to optimize and validate a 3-dimensional (3D) sampling perfection with application-optimized contrasts using different flip-angle evolution (SPACE) sequence for quantification of T2 signal in the LA, and to apply it in recently ablated patients, comparing myocardial edema on T2-SPACE to tissue damage on late gadolinium enhancement (LGE) imaging., Methods: Phantom studies were performed to identify 3D-SPACE parameters for optimal contrast between normal and edematous myocardium. Fourteen AF patients were imaged with both 3D-SPACE and dark-blood turbo-spin echo (DB-TSE) to compare image quality and signal intensity between the 2 techniques. Eight patients underwent pre- and postablation 3D-SPACE and 3D-LGE imaging. Ablation points were co-registered with corresponding myocardial sectors, and ablation-induced changes in T2 and LGE signal intensities were measured., Results: Signal-to-noise ratio and contrast-to-noise ratio were higher on SPACE vs DB-TSE (65.5 ± 33.9 vs 35.7 ± 17.9; P = .01; and 59.4 ± 33.0 vs 32.9 ± 17.7; P = .04, respectively). T2-signal correlated well on 3D-SPACE and DB-TSE, such that each unit increase in TSE intensity correlated with a 0.69-unit increase in SPACE intensity (95% confidence interval 0.56-0.82; P <.001). T2 and LGE signal intensities were acutely increased at ablation sites. The extent of postablation edema was higher compared to LGE, although the spatial distribution of hyperenhancement around pulmonary veins seemed similar in both modalities., Conclusion: T2-SPACE can be used to map the extent of acute postablation edema in the thin LA myocardium, with improved resolution and lower artifact compared to traditional DB-TSE., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Prior studies identified a relationship between epicardial bipolar and endocardial unipolar voltage. Whether the relationship is valid with smaller multielectrode mapping catheters has not been reported. We explored the association of right ventricular (RV) endocardial unipolar voltage mapping with epicardial bipolar voltage mapping using a multielectrode mapping catheter., Methods: Electrograms from patients who underwent multielectrode endocardial and epicardial RV electroanatomical mapping during ablation procedures were analyzed. Each endocardial mapping point was matched to the corresponding nearest epicardial point. The correlation between unipolar endocardial voltage and epicardial bipolar voltage was determined. The optimal unipolar threshold to detect epicardial low voltage (< 1.0 mV) and dense scar (0.5 mV) was calculated., Results: A total of 4,895 points were analyzed. There was a significant correlation between endocardial unipolar and epicardial bipolar voltage (Spearman rho  =  0.499, P  =  < 0.001). The extent of the correlation was inversely associated with wall thickness. The receiver operator characteristic analysis of endocardial unipolar voltage predicting epicardial bipolar voltage of < 1.0 mV and < 0.5 showed an area under the curve of 0.769 and 0.812, respectively. The endocardial unipolar voltage that had the highest sensitivity and specificity in detecting epicardial bipolar voltage of < 1.0 mV and < 0.5 mV was 3.3 mV (70.3% sensitivity, 70.3% specificity), and 2.8 mV (sensitivity 73.8%, specificity 73.3%), respectively., Conclusion: Epicardial low voltage of the RV can be assessed by unipolar endocardial voltage using small multielectrode catheters. The strength of the association was inversely correlated with the wall thickness., (© 2018 Wiley Periodicals, Inc.)

Introduction: Catheter ablation is common for patients with symptomatic, drug-refractory atrial fibrillation (AF). Obesity is a known risk factor for incident AF. The impact of obesity on AF ablation outcomes is incompletely understood. We sought to determine the impact of elevated body mass index (BMI) on pulmonary vein isolation (PVI) procedural outcomes and associated complications., Methods and Results: We evaluated patients undergoing PVI from 2001 to 2015, dividing them into four groups: normal weight (BMI ≥ 18.5 to < 25), overweight (BMI ≥ 25 to < 30), obese (BMI > 30 to < 40), and morbidly obese (BMI ≥ 40). Demographic and procedural characteristics, complications, and ablation outcomes were compared among groups. A total of 701 patients (146 time-matched controls, 227 overweight, 244 obese, and 84 morbidly obese) with complete demographic, procedural, and follow-up data were included. Increasing BMI correlated positively with HTN, OSA, CHA 2 DS 2 -VASC score, and persistent AF (P ≤ 0.001 for all associations). Radiofrequency application time and intraprocedural heparin dose increased with BMI (P ≤ 0.001). Arrhythmia recurrence at 1 year was 39.9% in controls, while higher in all high-BMI groups (overweight, 51.3%; obese, 57%; morbidly obese, 58.1 %; P  =  0.007 for all versus controls). Impact of BMI on AF recurrence was not seen in persistent AF patients. Complication rates across groups were similar., Conclusions: AF recurrence after catheter ablation is higher in overweight, obese, and morbidly obese patients comparing to normal-weight controls, driven primarily by outcomes differences in paroxysmal AF patients. Complications were not associated with increased BMI., (© 2017 Wiley Periodicals, Inc.)

Background: Bipolar voltage mapping, as part of atrial fibrillation (AF) ablation, is traditionally performed in a point-by-point (PBP) approach using single-tip ablation catheters. Alternative techniques for fibrosis-delineation include fast-anatomical mapping (FAM) with multi-electrode circular catheters, and late gadolinium-enhanced magnetic-resonance imaging (LGE-MRI). The correlation between PBP, FAM, and LGE-MRI fibrosis assessment is unknown., Objective: In this study, we examined AF substrate using different modalities (PBP, FAM, and LGE-MRI mapping) in patients presenting for an AF ablation., Methods: LGE-MRI was performed pre-ablation in 26 patients (73% males, age 63±8years). Local image-intensity ratio (IIR) was used to normalize myocardial intensities. PBP- and FAM-voltage maps were acquired, in sinus rhythm, prior to ablation and co-registered to LGE-MRI., Results: Mean bipolar voltage for all 19,087 FAM voltage points was 0.88±1.27mV and average IIR was 1.08±0.18. In an adjusted mixed-effects model, each unit increase in local IIR was associated with 57% decrease in bipolar voltage (p<0.0001). IIR of >0.74 corresponded to bipolar voltage <0.5 mV. A total of 1554 PBP-mapping points were matched to the nearest FAM-point. In an adjusted mixed-effects model, log-FAM bipolar voltage was significantly associated with log-PBP bipolar voltage (ß=0.36, p<0.0001). At low-voltages, FAM-mapping distribution was shifted to the left compared to PBP-mapping; at intermediate voltages, FAM and PBP voltages were overlapping; and at high voltages, FAM exceeded PBP-voltages., Conclusion: LGE-MRI, FAM and PBP-mapping show good correlation in delineating electro-anatomical AF substrate. Each approach has fundamental technical characteristics, the awareness of which allows proper assessment of atrial fibrosis., Competing Interests: Disclosures: The other authors report no conflicts.

Background: The extent of left atrial (LA) baseline low-voltage areas (LVA-B), which may be a surrogate for fibrosis, is associated with recurrent atrial fibrillation (AF) after ablation. This study aimed to assess the relationship between the extent of LVA-B isolated by ablation (LVA-I) and AF recurrence., Methods: The study cohort included 159 consecutive patients with drug-refractory AF who underwent an initial AF ablation with LA voltage mapping during sinus rhythm. The extent of LVA-B was quantified while excluding the pulmonary veins, LA appendage, and mitral valve area. LVA-I was quantified as the percentage of LVA-B encircled by pulmonary vein isolation. Surveillance and symptom-prompted electrocardiograms, Holter monitors, and event monitors were used to document atrial arrhythmia recurrence for a median follow-up of 712 days (1.95 years)., Results: Of 159 patients, 72% were men and 27% had persistent AF. The mean number of sampled bipolar voltage points was 119 ± 56. The mean LA surface area was 102.3 ± 37.3 cm 2 , and the mean LVA-B was 1.9 ± 3.8 cm 2 . The mean LVA-I was 51.05% ± 36.8% of LVA-B. In the multivariable Cox proportional hazards model adjusted for LA volume, CHA 2 DS 2 -VASc (Congestive Heart Failure, Hypertension, Age [≥ 75 years], Diabetes, Stroke/Transient Ischemic Attack, Vascular Disease, Age [65-74 years], Sex [Female] score), LVA-B, and AF type, LVA-I was inversely associated with recurrent atrial arrhythmia after the blanking period (hazard ratio, 0.42/percent LVA isolated; P = 0.037)., Conclusions: The extent of LVA-I is independently associated with freedom from atrial arrhythmias after AF ablation, supporting ongoing efforts to target low LA voltage areas and other fibrosis indicators to improve ablation outcomes., (Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: The utility of rotor ablation using commercially available systems as an adjunct to pulmonary vein isolation (PVI) is controversial. Variable results may stem from heterogeneous practice patterns. We investigated whether a prespecified protocol to determine temperospatial rotor stability improved acute and intermediate outcomes following rotor ablation., Hypothesis: Protocolized rotor mapping and ablation, with prespecified metrics to determine temporal rotor stability prior to ablation, will improve short- and long-term PVI/rotor ablation outcomes., Methods: Patients undergoing PVI plus rotor ablation at Johns Hopkins during 2015 were included. The first cohort underwent rotor mapping and ablation at the operator's discretion, whereas the second cohort underwent protocolized rotor mapping, with ablation limited to temperospatially stable rotors. Both cohorts underwent PVI. Acute results (rotor elimination, atrial fibrillation [AF] termination), procedural data, and 1-year outcomes were assessed., Results: Twenty-seven patients underwent ablation (mean age, 64.4 ± 9 years, male 81.5%, persistent AF 85.2%, long-standing persistent AF 14.8%, mean AF duration 4.4 ± 4 years, repeat cases 51.8%, and mean LA size 4.6 ± 0.8 cm). In the protocolized cohort, rotors were reproducible in 83% (10/12) of cases in at least 1 chamber. Acute rhythm change was achieved in 8/27 (29.6%) patients. Sinus rhythm on presentation (62.5% vs 15.8%, P = 0.03) and higher total targeted rotors (3.8 ± 1.7 vs 2.5 ± 1.0, P = 0.02) predicted acute change. At 12 months, freedom from AF/atrial tachycardia was achieved in 5/15 (33.3%) patients in the first cohort and 5/11 patients in the protocolized cohort (45.5%; P = 0.53 for comparison)., Conclusions: Acute and intermediate results did not change with protocolized mapping designed to identify temperospatially stable rotors. Outcomes at 12 months were similar in both groups., (© 2017 Wiley Periodicals, Inc.)

Objectives: This study assessed trends in transesophageal echocardiography (TEE) use, rate of left atrial appendage (LAA) thrombus detection, and incidence of periprocedural cerebrovascular accident (CVA) since transitioning to a strategy of uninterrupted warfarin or briefly interrupted novel oral anticoagulant therapy in 2010., Background: TEE is routinely performed before ablation for atrial fibrillation (AF) to ensure absence of LAA thrombus., Methods: Patients with AF ablation presenting between January 2010 and September 2015 at Johns Hopkins Hospital were enrolled in an AF ablation registry; TEE and ablation outcomes were retrospectively analyzed. Presence of LAA thrombus, dense spontaneous echo contrast (SEC), or patent foramen ovale (PFO) were recorded. CVA incidence from procedure onset to 30 days post-procedure was evaluated using electronic medical record review., Results: Pre-procedure TEE was performed in 646 of 1,224 AF ablation cases (52.8%). There was a decline in pre-procedure TEE use from 86% in 2010 to 42% in 2015 (p < 0.001). CVA incidence was 4/1,224 (0.33%) cases, and did not change during the study period. TEE findings included LAA thrombus (n = 6; 0.93%), PFO (n = 23; 3.6%), and dense spontaneous echo contrast (n = 99; 15.3%). Both SEC and LAA thrombus were associated with persistent AF, higher CHA 2 DS 2 VASC score, increased LA size, reduced LAA flow velocity, and decreased left ventricular ejection fraction. PFO was not associated with prior AF ablation, and SEC was not associated with increased CVA incidence., Conclusions: CVA is a rare complication of AF ablation in patients with minimally interrupted anticoagulation. Pre-ablation TEE may be reasonably avoided in patients without high-risk features., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: We sought to describe the prevalence and variability of coronary sinus (CS) and left atrial (LA) myocardium connections, their susceptibility to rate-dependent conduction block, and association with atrial fibrillation (AF) and flutter induction., Methods and Results: The study cohort included 30 consecutive AF patients (age 63.3±10.5 years, 63% male). Multipolar catheters were positioned in the CS, high right atrium (HRA), and LA parallel to and near the CS. Trains of 10 pacing stimuli were delivered during sinus rhythm from each of the following sites: CS proximal (CS p ), CS distal (CS d ), LA septum (LA s ), lateral LA (LA l ), and HRA, at the following cycle lengths: 1000, 500, 400, 300, and 250 ms, while recording from the other catheters. With the CS 9 to 10 bipole just inside the CS ostium, CS-LA connections were observed in 100% at CS 9 to 10, 30% at CS 7 to 8, 23% at CS 5 to 6, 23% at CS 3 to 4, and 97% at CS 1 to 2. Eighteen patients (60%) had AF/atrial flutter induced. Rate-dependent conduction block of a CS-LA connection at cycle length of ≥250 ms was present in 17 (94%) of those with versus none of those without AF/atrial flutter induction (P<0.001)., Conclusions: Rate-dependent eccentric CS-LA conduction block is associated with AF/atrial flutter induction in patients with drug-refractory AF undergoing ablation. The presence of dual muscular CS-LA connections, coupled with unidirectional block in one limb, seems to serve as a substrate for single or multiple reentry beats, and arrhythmia induction., (© 2016 American Heart Association, Inc.)

Background: Epicardial adipose tissue (EAdT) is metabolically active and likely contributes to atrial fibrillation (AF) through the release of inflammatory cytokines into the myocardium or through its rich innervation with ganglionated plexi at the pulmonary vein ostia. The electrophysiologic mechanisms underlying the association between EAdT and AF remain unclear., Objective: The purpose of this study was to investigate the association of EAdT with adjacent myocardial substrate., Methods: Thirty consecutive patients who underwent cardiac computed tomography as well as electroanatomic mapping in sinus rhythm before an initial AF ablation procedure were studied. Semiautomatic segmentation of atrial EAdT was performed and registered anatomically to the voltage map., Results: In multivariable regression analysis clustered by patient, age (-0.01 per year) and EAdT (-0.29) were associated with log bipolar voltage as well as low-voltage zones (<0.5 mV). Age (odds ratio [OR]: 1.02 per year), male gender (OR: 3.50), diabetes (OR: 2.91), hypertension (OR: 2.55), and EAdT (OR: 8.56) were associated with fractionated electrograms, and age (OR: 2.80), male gender (OR: 3.00), and EAdT (OR: 7.03) were associated with widened signals. Age (OR: 1.03 per year) and body mass index (OR: 1.06 per kg/m 2 ) were associated with atrial fat., Conclusion: The presence of overlaying EAdT was associated with lower bipolar voltage and electrogram fractionation as electrophysiologic substrates for AF. EAdT was not a statistical mediator of the association between clinical variables and AF substrate. Body mass index was directly associated with the presence of EAdT in patients with AF., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)