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Objectives The aim of this study was to evaluate the efficacy of radiofrequency (RF) energy applications targeting the atrial side of a significant residual leak in patients with acute and chronic evidence of incomplete percutaneous left atrial appendage (LAA) occlusion. Background RF applications have been proved to prevent recanalization of intracranial aneurysms after coil embolization, thereby favoring complete sealing. From a mechanistic standpoint, in vitro and in vivo experiments have demonstrated that RF promotes collagen deposition and tissue retraction. Methods Forty-three patients (mean age 75 ± 7 years mean CHA2DS2-VASc score 4.6 ± 1.4, mean HAS-BLED score 4.0 ± 1.1) with residual leaks ≥4 mm after Watchman implantation were enrolled. Procedural success was defined as complete LAA occlusion or presence of a mild or minimal (1- to 2-mm) peridevice leak on follow-up transesophageal echocardiography (TEE), which was performed approximately 45 days after the procedure. Results RF-based leak closure was performed acutely after Watchman implantation in 19 patients (44.2%) or scheduled after evidence of significant leaks on follow-up TEE in 24 others (55.8%). The median leak size was 5 mm (range: 4-7 mm). On average, 18 ± 7 RF applications per patient (mean maximum contact force 16 ± 3 g, mean power 44 ± 2 W, mean RF time 5.1 ± 2.5 minutes) were performed targeting the atrial edge of the leak. Post-RF median leak size was 0 mm (range: 0-1 mm). A very low rate (2.3% [n = 1]) of major periprocedural complications was observed. Follow-up TEE revealed complete LAA sealing in 23 patients (53.5%) and negligible residual leaks in 15 (34.9%). Conclusions RF applications targeting the atrial edge of a significant peri-Watchman leak may promote LAA sealing via tissue remodeling, without increasing complications. (RF Applications for Residual LAA Leaks [REACT]; NCT04726943 )

Objectives This study evaluated the long-term efficacy of a standard antithrombotic strategy versus half-dose direct oral anticoagulation (DOAC) after Watchman implantation. Background No consensus currently exists on the selection of the most effective antithrombotic strategy to prevent device-related thrombosis (DRT) in patients undergoing endocardial left atrial appendage closure. Methods After successful left atrial appendage closure, consecutive patients were prescribed a standard antithrombotic strategy (SAT) or long-term half-dose DOAC (hdDOAC). The primary composite endpoint was DRT and thromboembolic (TE) and bleeding events. Results Overall, 555 patients (mean age 75 ± 8 years, 63% male; median CHA2DS2-VASc [congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack or thromboembolism, vascular disease, age 65-74 years, sex category] score 4 [interquartile range (IQR): 3-6]; median HAS-BLED [hypertension, abnormal renal or liver function, stroke, bleeding, labile international normalized ratio, elderly, drugs or alcohol] score 3 [IQR: 2-4]) were included. Patients were categorized into 2 groups (SAT: n = 357 vs hdDOAC: n = 198). Baseline clinical characteristics were similar between groups. The median follow-up duration was 13 months (IQR: 12-15 months). DRT occurred in 12 (2.1%) patients, all in the SAT group (3.4% vs 0.0%; log-rank P = 0.009). The risk of nonprocedural major bleeding was significantly more favorable in the hdDOAC group (0.5% vs. 3.9%; log-rank P = 0.018). The rate of the primary composite endpoint of DRT and TE and major bleeding events was 9.5% in SAT patients and 1.0% in hdDOAC patients (HR: 9.8; 95% CI: 2.3-40.7; P = 0.002). Conclusions After successful Watchman implantation, long-term half-dose DOAC significantly reduced the risk of the composite endpoint of DRT and TE and major bleeding events compared with a standard, antiplatelet-based, antithrombotic therapy.

Background Fragmented QRS (fQRS) on 12-lead electrocardiography is a noninvasive marker of intramyocardial conduction delay due to ventricular scarring that has not previously been studied in atrial fibrillation. Objective The purpose of this study was to assess the association of fQRS with left atrial (LA) scarring in patients with persistent atrial fibrillation (PsAF) undergoing first catheter ablation. Methods A total of 376 patients with PsAF were enrolled. Severity of LA scarring was assessed using electroanatomic mapping. Narrow fQRS was defined by the presence of an additional R wave (R′) or notching in the nadir of the S wave, or the presence of >1 R′ in 2 contiguous leads corresponding to inferior, lateral, or anterior myocardial regions. Results Both any degree (97.3% vs 63.3%) and severe (42.2% vs 6.3%) LA scarring were higher in patients with fQRS. Age and fQRS were found to be independent predictors of severe LA scarring. At multiple ventricular regions, fQRS had diagnostic accuracy of 79.8% for prediction of severe LA scarring. Nonpulmonary vein triggers were more often detected and ablated in patients with fQRS and severe LA scarring (84.4% vs 70%; P = .001). Atrial tachyarrhythmia recurrence was observed in 131 patients (34.8%) during 18.9 ± 7.7 months of follow-up, which was significantly higher in patients with fQRS (53.2% vs 16.8%). In multivariate analysis, fQRS was found to be a significant predictor of recurrence (hazard ratio 4.65; 95% interval confidence 2.91–7.42; P Conclusion The study results showed that fQRS is a simple, available, and noninvasive marker, and that fQRS at multiple ventricular regions is significantly associated with the severity of LA scarring in PsAF patients.

Background Atrial fibrillation (AF) triggers within the coronary sinus (CS)/great cardiac vein (GCV) and the left atrial appendage (LAA) have been recognized as nonpulmonary vein triggers of AF. Objective The aim of this study was to describe an electrical connection between the LAA and CS/GCV and its importance in achieving LAA electrical isolation (LAAEI). Methods A total of 488 consecutive patients undergoing catheter ablation for persistent or long-standing persistent AF who showed firing from the LAA and/or from the CS/GCV were enrolled in this multicenter prospective study. In all patients, potential defragmentation of the CS/GCV to achieve isolation and LAAEI was attempted with both endocardial and epicardial ablation. Results In 7% (n = 34) of these patients, after attempting endocardial LAAEI, the LAA was isolated during epicardial ablation in the GCV. In 8% (n = 39) of patients after attempting endocardial LAA isolation, the LAA was isolated during ablation along the endocardial aspect of the GCV. The presence of a venous branch connecting the GCV with the LAA was found in all these patients. In 23% (n = 112) of patients, the isolation of the LAA also isolated the GCV. In all these patients, LAA dissociated firing was present together with the CS/GCV recordings. Conclusion These findings suggest the presence of a distinct electrical connection between the GCV and the LAA. The clinical relevance of our results requires further investigation. Ablation in the CS/GCV can result in inadvertent isolation of the LAA. Ablation of the GCV is relevant to achieve LAAEI. Considering the potential long-term implications, ablation in the distal CS/GCV should prompt assessment of LAA conduction.

Background An increasing number of adults with congenital heart disease (CHD) are undergoing catheter ablation for atrial fibrillation (AF). Data on ablation strategy and outcomes in CHD are limited. Rhythm control is often believed to be of greater importance among patients with complex CHD. Objective The purpose of this study was to examine the safety and efficacy of AF ablation in adult patients with CHD. Methods A multicenter retrospective analysis was performed of CHD patients undergoing AF ablation. Clinical data were collected, including AF and CHD type, procedural data, and outcomes. Patients were divided into 3 groups (simple, moderate, and severe) based on CHD complexity, as defined by the 2014 PACES/HRS (Pediatric and Congenital Electrophysiology Society/Heart Rhythm Society) consensus statement. One-year procedural success was defined as freedom from recurrent AF, off antiarrhythmic drugs (complete) or off/on previously failed antiarrhythmic drugs (partial). Results Overall, 84 CHD patients (mean age 51.5 ± 12.1 years; 65.5% male; 45.2% with paroxysmal AF) undergoing AF ablation (51 simple, 22 moderate, 11 severe complexity) were included. Pulmonary vein isolation was performed in 80 (95.2%), of whom 30 (35.7%) underwent pulmonary vein isolation alone. Overall, complete and complete/partial freedom was achieved at 1 year in 53.1% and 71.6%, respectively, with no significant differences between those with simple, moderate, or severe complexity. There were no major complications and 7 minor complications, and 2 patients died during follow-up. Conclusion There are dramatic differences in the degree of CHD complexity among patients referred for AF ablation. When performed at experienced centers, AF ablation is safe and effective even among patients with the most complex forms of CHD.

The optimal site of ablation of idiopathic left ventricular outflow tract (LVOT) ventricular arrhythmias (VAs) is challenging as activation mapping can reveal similar activation times in different anatomical sites, suggesting an intramural origin.We sought to assess whether in patients with intramural VAs and with multiple early activation sites (EASs), sequential ablation of all the early EASs could improve acute and long-term clinical outcomes.A total of 116 patients undergoing catheter ablation for symptomatic LVOT VAs were enrolled in this study. Thirty-nine patients (34%) were referred for a redo procedure, whereas the remaining presented for a first procedure. Mapping was performed manually in 86 cases (74%) and with a magnetic robotic system (Niobe, Stereotaxis, St. Louis, MO) in the remainder of the cases.Of the 116 patients, 15 (13%) were found to have multiple sites of equally early activation. In patients with multiple EASs, the mean pre-QRS activation time was significantly less than in patients with a single EASs (-26 ± 3 ms vs -38 ± 6 ms; P .005). Sequential ablation of all the EASs was possible in 14 patients (93%), resulting in complete arrhythmia suppression. After a mean follow-up of 21 ± 5 months, all patients with successful ablation of all multiple early EASs remained free from clinical VAs.Intramural LVOT VAs manifesting with multiple EASs require ablation at all sites to achieve acute and long-term success, particularly if none of the EASs is-30ms pre-QRS activation time.

Objectives This study sought to characterize ventricular tachycardia (VT) ablation outcomes across nonischemic cardiomyopathy (NICM) etiologies and adjust these outcomes by patient-related comorbidities that could explain differences in arrhythmia recurrence rates. Background Outcomes of catheter ablation of VT in patients with NICM could be related to etiology of NICM. Methods Data from 2,075 patients with structural heart disease referred for catheter ablation of VT from 12 international centers was retrospectively analyzed. Patient characteristics and outcomes were noted for the 6 most common NICM etiologies. Multivariable Cox proportional hazards modeling was used to adjust for potential confounders. Results Of 780 NICM patients (57 ± 14 years of age, 18% women, left ventricular ejection fraction 37 ± 13%), underlying prevalence was 66% for dilated idiopathic cardiomyopathy (DICM), 13% for arrhythmogenic right ventricular cardiomyopathy (ARVC), 6% for valvular cardiomyopathy, 6% for myocarditis, 4% for hypertrophic cardiomyopathy, and 3% for sarcoidosis. One-year freedom from VT was 69%, and freedom from VT, heart transplantation, and death was 62%. On unadjusted competing risk analysis, VT ablation in ARVC demonstrated superior VT-free survival (82%) versus DICM (p ≤ 0.01). Valvular cardiomyopathy had the poorest unadjusted VT-free survival, at 47% (p Conclusions Catheter ablation of VT in NICM is effective. Etiology of NICM is a significant predictor of outcomes, with ARVC, myocarditis, and DICM having similar but superior outcomes to hypertrophic cardiomyopathy, valvular cardiomyopathy, and sarcoidosis, after adjusting for potential covariates.

Objectives This study reports outcomes of bailout atrial balloon septoplasty (ABS) to overcome challenging left atrial (LA) access in patients undergoing atrial fibrillation (AF) ablation. Background Transseptal puncture (TSP) and LA access for AF ablation can be challenging in patients with prior atrial septal surgery, percutaneous closure, or scarred septum due to multiple prior TSPs. Methods The study identified patients who underwent AF ablation at 2 ablation centers from 2011 to 2017 with challenging TSP in whom bailout percutaneous ABS was performed to allow LA access. Following TSP, the transseptal sheath could not be advanced to the LA despite multiple attempts or approaches including use of a stiff wire sequentially in the left and right pulmonary veins, use of a stiff pigtail exchange wire advanced in the LA or left ventricle, or sequential dilation with progressively larger diameter long dilators. ABS was performed using a noncompliant balloon (diameter 4 to 10 mm) advanced over a stiff wire deployed in the left superior pulmonary vein, allowing passage of the transseptal sheaths for completion of the AF ablation procedure. Results Fifteen patients (mean age 54.4 ± 15.5 years, 9 women) with challenging TSP (7 patients with prior surgical ASD repair, 2 with percutaneous ASD closure devices, and 13 with ≥1 previous TSP) underwent bailout ABS for AF ablation. After TSP (radiofrequency assisted in 10 cases), ABS was successful and permitted access to the LA for ablation in all patients. Mean time required to perform ABS was 21.3 ± 19.4 min, and mean total procedure time was 241.1 ± 114.6 min (fluoroscopy time 62.0 ± 29.9 min). There were no procedural complications. Conclusions In patients undergoing AF ablation with difficult transseptal access due to scarred, surgically, or percutaneously repaired atrial septum, ABS is a safe and effective bailout strategy to obtain transseptal access.

The purpose of this study was to evaluate the characteristics and outcome of patients undergoing ablation after electrical storm (ES).Clinical and procedural characteristics, ventricular tachycardia (VT) recurrence, and mortality rates from 1940 patients undergoing VT ablation were compared between patients with and without ES.The group of 677 patients with ES (34.9%) were older, were more frequently men, and had a lower ejection fraction, more advanced heart failure, and a higher prevalence of cardiovascular comorbidities as compared with those without ES (86.1% patients with ES had ≥2 comorbidities vs 71.4%; P.001). Patients with ES had more inducible VTs (2.5 ± 1.8 vs 1.9 ± 1.9; P.001), required longer procedures (296.1 ± 119.1 minutes vs 265.7 ± 110.3 minutes; P.001), and had a higher in-hospital mortality (42 deaths [6.2%] vs 18 deaths [1.4%]; P.001). At 1-year follow-up, patients with ES experienced a higher risk of VT recurrence and mortality (32.1% vs 22.6% and 20.1% vs 8.5%; long-rank, P.001 for both). Among patients with ES, those without any inducible VT after ablation had a higher survival rate (86.3%) than did those with nonclinical VTs only (72.9%), those with clinical VTs inducible at programmed electrical stimulation (51.2%), and not-tested patients (65.0%) (long-rank, P.001 for all). In multivariate analysis, ES remained an independent predictor of in-hospital mortality, VT recurrence, and 1-year mortality (P.001).Patients with ES have a high risk of VT recurrence and mortality. Patient and procedure characteristics are consistent with advanced cardiac disease and longer and more complex procedures. In patients with ES, acute procedural success is associated with a significant reduction in VT recurrence and improved 1-year survival.

Background: Longstanding persistent (LSP) atrial fibrillation (AF) is the most challenging type of AF. In addition to pulmonary vein isolation, substrate modification and triggers ablation ...

Catheter ablation has become a widely available and accepted treatment to restore sinus rhythm in atrial fibrillation patients who fail antiarrhythmic drug therapy. Although generally safe, the procedure carries a non-negligible risk of complications, including periprocedural cerebral insults. Uninterrupted anticoagulation, maintenance of an adequate ACT during the procedure, and measures to avoid and detect thrombus build-up on sheaths and atheters during the procedure, appears useful to reduce the risk of embolic events. This is a review of the incidence, mechanisms, impact, and methods to reduce catheter ablation related cerebral insults.

The aim of this study was to evaluate the incidence and clinical implications of leaks (acute incomplete occlusion, early and late reopenings) following LAA ligation with the LARIAT device.Percutaneous LAA ligation with the LARIAT device may represent an alternative for stroke prevention in high-risk patients with atrial fibrillation with contraindications to oral anticoagulation.This was a retrospective, multicenter study of 98 consecutive patients undergoing successful LAA ligation with the LARIAT device. Leaks were defined as the presence of flow as evaluated by transesophageal echocardiography (TEE). TEE was performed during the procedure, at 6 and 12 months, and after thromboembolic events.Leaks were detected in 5 (5%), 14 (15%), and 19 (20%) patients at the 3 time points. During follow-up, 5 patients developed neurological events (4 strokes and 1 transient ischemic attack). Two occurred early (1 fatal stroke and 1 stroke with multiple recurrences in the following months), and TEE was not repeated after the events. The remaining 3 occurred late (after 6 months) and were associated with small leaks (5 mm). In 2 of 3 cases, such a small leak was missed by the standard evaluation on 2-dimensional TEE, being evident only with the aid of 3-dimensional imaging.Incomplete occlusion of the LAA after LARIAT ligation is relatively common and may be associated with thromboembolic events. Proper long-term surveillance with careful TEE should be considered to detect leaks, which can be managed with either resumption of oral anticoagulation or percutaneous transcatheter closure.

Background Focal impulse and rotor modulation (FIRM)-guided ablation targets sites that are thought to sustain atrial fibrillation (AF). Objective The purpose of this study was to evaluate the acute and mid-term outcomes of FIRM-guided only ablation in patients with nonparoxysmal AF. Methods We prospectively enrolled patients with persistent and long-standing persistent (LSP) AF at three centers to undergo FIRM-guided only ablation. We evaluated acute procedural success (defined as AF termination, organization, or ≥10% slowing), safety (incidence of periprocedural complications), and long-term success (single-procedure freedom from atrial tachycardia [AT]/AF off antiarrhythmic drugs [AAD] after a 2-month blanking period). Results Twenty-nine patients with persistent (N = 20) and LSP (N = 9) AF underwent FIRM mapping. Rotors were presents in all patients, with a mean of 4 ± 1.2 per patient (62% were left atrial); 1 focal impulse was identified. All sources were successfully ablated, and overall acute success rate was 41% (0 AF termination, 2 AF slowing, 10 AF organization). There were no major procedure-related adverse events. After a mean 5.7 months of follow-up, single-procedure freedom from AT/AF without AADs was 17%. Conclusion In nonparoxysmal AF patients, targeted ablation of FIRM-identified rotors is not effective in obtaining AF termination, organization, or slowing during the procedure. After mid-term follow-up, the strategy of ablating FIRM-identified rotors alone did not prevent recurrence from AT/AF.

It is unclear whether isolation of the left atrial posterior wall (LAPW) offers additional benefits over pulmonary vein antrum isolation (PVAI) alone in patients with persistent atrial fibrillation (AF).We sought to determine the impact of PVAI and LAPW isolation (PVAI+LAPW) versus PVAI alone on the outcome of ablation of persistent AF.During the first procedure, PVAI was performed in 20 patients (group 1), whereas in 32 patients (group 2), PVAI was extended to the left atrial (LA) septum and coronary sinus (CS), and isolation of the LAPW was targeted (ePVAI+LAPW). Isolation of the superior vena cava was achieved in both groups. All patients, regardless of arrhythmia recurrence, underwent a second procedure 3 months after the first procedure. In patients with reconnection of pulmonary veins or LAPW, reisolation was performed, and a third procedure was performed 3 months later to verify isolation. Patients entered follow-up only after PVAI (group 1) or PVAI+LAPW (group 2) isolation was proven.At the 1-, 2-, and 3-year follow-up examinations, the rates of freedom from atrial tachyarrhythmia without use of an antiarrhythmic drug were 20%, 15%, and 10% in group 1 and 65%, 50%, and 40% in group 2, respectively (log-rank P.001). The median recurrence-free survival time was 8.5 months (interquartile range 6.5-11.0) in group 1 and 28.0 months (interquartile range 8.5-32.0) in group 2.Proven isolation of the LAPW provides additional benefits over PVAI alone in the treatment of persistent AF and improves procedural outcome at follow-up. However, the ablation strategy of ePVAI+LAPW is still associated with a significant high incidence of very late recurrence of atrial tachyarrhythmia."Outcome of Atrial Fibrillation Ablation After Permanent Pulmonary Vein Antrum Isolation With or Without Proven Left Atrial Posterior Wall Isolation" (LIBERATION). ClinicalTrials.gov Identifier: NCT01660100.

Background Catheter ablation reduces ventricular tachycardia (VT) recurrence and implantable cardioverter defibrillator shocks in patients with VT and ischemic cardiomyopathy. The most effective catheter ablation technique is unknown. Objectives This study determined rates of VT recurrence in patients undergoing ablation limited to clinical VT along with mappable VTs (“clinical ablation”) versus substrate-based ablation. Methods Subjects with ischemic cardiomyopathy and hemodynamically tolerated VT were randomized to clinical ablation (n = 60) versus substrate-based ablation that targeted all “abnormal” electrograms in the scar (n = 58). Primary endpoint was recurrence of VT. Secondary endpoints included periprocedural complications, 12-month mortality, and rehospitalizations. Results At 12-month follow-up, 9 (15.5%) and 29 (48.3%) patients had VT recurrence in substrate-based and clinical VT ablation groups, respectively (log-rank p Conclusions An extensive substrate-based ablation approach is superior to ablation targeting only clinical and stable VTs in patients with ischemic cardiomyopathy presenting with tolerated VT. (Ablation of Clinical Ventricular Tachycardia Versus Addition of Substrate Ablation on the Long Term Success Rate of VT Ablation (VISTA); NCT01045668 )

Although cardiac resynchronization therapy (CRT) is an important treatment of symptomatic heart failure patients in sinus rhythm with low left ventricular ejection fraction and ventricular dyssynchrony, its role is not well defined in patients with atrial fibrillation (AF). CRT is not as effective in patients with AF because of inadequate biventricular capture and loss of atrioventricular synchrony. Both can be addressed with catheter ablation of AF. It is still unclear if these therapies offer additive benefits in patients with ventricular dyssynchrony. This article discusses the role and techniques of catheter ablation of AF in patients with heart failure, and its application in CRT recipients.

Background Transcatheter left atrial appendage (LAA) ligation may represent an alternative to oral anticoagulation for stroke prevention in atrial fibrillation. Objectives This study sought to assess the early safety and efficacy of transcatheter ligation of the LAA for stroke prevention in atrial fibrillation. Methods This was a retrospective, multicenter study of consecutive patients undergoing LAA ligation with the Lariat device at 8 U.S. sites. The primary endpoint was procedural success, defined as device success (suture deployment and Results A total of 154 patients were enrolled. Median CHADS2 score (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke, transient ischemic attack, or thromboembolism [doubled]) was 3 (interquartile range: 2 to 4). Device success was 94%, and procedural success was 86%. A major complication occurred in 15 patients (9.7%). There were 14 major bleeds (9.1%), driven by the need for transfusion (4.5%). Significant pericardial effusion occurred in 16 patients (10.4%). Follow-up was available in 134 patients at a median of 112 days (interquartile range: 50 to 270 days): Death, myocardial infarction, or stroke occurred in 4 patients (2.9%). Among 63 patients with acute closure and transesophageal echocardiography follow-up, there were 3 thrombi (4.8%) and 13 (20%) with residual leak. Conclusions In this initial multicenter experience of LAA ligation with the Lariat device, the rate of acute closure was high, but procedural success was limited by bleeding. A prospective randomized trial is required to adequately define clinical efficacy, optimal post-procedure medical therapy, and the effect of operator experience on procedural safety.

This article addresses the use of catheter ablation (CA) as first-line therapy for atrial fibrillation (AF). CA increases long-term freedom from AF, reduces hospitalizations, and improves quality of life compared with antiarrhythmic drug (AAD) therapy in patients with symptomatic AF who have already failed one AAD. The role of CA as first-line therapy for AF, however, is still controversial. Evidence from randomized controlled trials shows that CA is definitely superior to AADs as first-line therapy for relatively young patients with paroxysmal AF, with comparable complication rates and results consistently reproducible across different institutions, operators, and types of ablation approaches.

Permanent pulmonary vein isolation constitutes the main procedural goal of current approaches to atrial fibrillation (AF) catheter ablation, with established effectiveness as a stand-alone procedure in most patients with paroxysmal AF. In patients with AF of longer duration, however, the definition of the optimal procedural end point is still controversial. Based on analysis of data from 16 studies that have assessed the value of AF termination in predicting long-term procedural success, it is concluded that AF termination clearly represents an unreliable procedural end point during ablation of nonparoxysmal AF.

Sosa and colleagues first described a percutaneous approach (via the subxiphoid area) to access the pericardial space in 1996. Epicardial mapping and ablation is increasingly used for the treatment of supraventricular and ventricular arrhythmias and represents an adjunctive approach for challenging arrhythmias to improve procedural success rates. Epicardial ablation should be considered not only after the failure of an endocardial ablation but often as a first-line approach. Complications may occur during percutaneous access and epicardial ablation, and these might be reduced or avoided by improved operator skills and experience. New tools to access the epicardial space are being evaluated.

Background Islets of myocytes within fibrofatty scars represent the substrate for reentrant ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy (ARVC). Electroanatomic mapping can reliably identify such areas. Objective To prospectively test the association between late and fragmented electrograms within scar and arrhythmic events in patients with ARVC. Methods High-density right ventricle electroanatomic mapping was performed in 32 patients with ARVC without history of cardiac arrest or sustained ventricular arrhythmias. Standard definitions of electroanatomic scars and fragmented, isolated, and very late potentials were used. All patients received an implantable cardioverter-defibrillator for the primary prevention of sudden death. Results After a mean follow-up of 25 ± 7 months, 12 (38%) patients received appropriate implantable cardioverter-defibrillator shock for sustained ventricular arrhythmias. With the exception of a higher rate of previous syncope ( P = .053), patients with arrhythmic events at follow-up did not differ from those who remained free from arrhythmic events in terms of other clinical variables, including cardiac magnetic resonance findings. Electroanatomic scars were present in all patients. The distribution and extent of electroanatomic scars were similar in the 2 groups (38 ± 25 cm 2 vs 33 ± 20 cm 2 ; P = .51). However, patients with implantable cardioverter-defibrillator shock had a higher prevalence of fragmented electrograms (92% vs 20%; P P = .004), and of very late potentials (67% vs 25%; P = .030). Fragmented electrograms were the only variable independently associated with arrhythmic events at follow-up (hazard ratio 21; P = .015). Conclusion The presence of fragmented and delayed electrograms within the scar predicts arrhythmic events in ARVC.

Objectives This study investigated the left atrial appendage (LAA) by computed tomography (CT) and magnetic resonance imaging (MRI) to categorize different LAA morphologies and to correlate the morphology with the history of stroke/transient ischemic attack (TIA). Background LAA represents one of the major sources of cardiac thrombus formation responsible for TIA/stroke in patients with atrial fibrillation (AF). Methods We studied 932 patients with drug-refractory AF who were planning to undergo catheter ablation. All patients underwent cardiac CT or MRI of the LAA and were screened for history of TIA/stroke. Four different morphologies were used to categorize LAA: Cactus, Chicken Wing, Windsock, and Cauliflower. Results CT scans of 499 patients and MRI scans of 433 patients were analyzed (age 59 ± 10 years, 79% were male, and 14% had CHADS2 [Congestive heart failure, Hypertension, Age >75, Diabetes mellitus, and prior Stroke or transient ischemic attack] score ≥2). The distribution of different LAA morphologies was Cactus (278 [30%]), Chicken Wing (451 [48%]), Windsock (179 [19%]), and Cauliflower (24 [3%]). Of the 932 patients, 78 (8%) had a history of ischemic stroke or TIA. The prevalence of pre-procedure stroke/TIA in Cactus, Chicken Wing, Windsock, and Cauliflower morphologies was 12%, 4%, 10%, and 18%, respectively (p = 0.003). After controlling for CHADS2 score, gender, and AF types in a multivariable logistic model, Chicken Wing morphology was found to be 79% less likely to have a stroke/TIA history (odd ratio: 0.21, 95% confidence interval: 0.05 to 0.91, p = 0.036). In a separate multivariate model, we entered Chicken Wing as the reference group and assessed the likelihood of stroke in other groups in relation to reference. Compared with Chicken Wing, Cactus was 4.08 times (p = 0.046), Windsock was 4.5 times (p = 0.038), and Cauliflower was 8.0 times (p = 0.056) more likely to have had a stroke/TIA. Conclusions Patients with Chicken Wing LAA morphology are less likely to have an embolic event even after controlling for comorbidities and CHADS2 score. If confirmed, these results could have a relevant impact on the anticoagulation management of patients with a low-intermediate risk for stroke/TIA.

Objectives The purpose of this study was to evaluate the feasibility and safety of uninterrupted rivaroxaban therapy during atrial fibrillation (AF) ablation. Background Optimal periprocedural anticoagulation strategy is essential for minimizing bleeding and thromboembolic complications during and after AF ablation. The safety and efficacy of uninterrupted rivaroxaban therapy as a periprocedural anticoagulant for AF ablation are unknown. Methods We performed a multicenter, observational, prospective study of a registry of patients undergoing AF ablation in 8 centers in North America. Patients taking uninterrupted periprocedural rivaroxaban were matched by age, sex, and type of AF with an equal number of patients taking uninterrupted warfarin therapy who were undergoing AF ablation during the same period. Results A total of 642 patients were included in the study, with 321 in each group. Mean age was 63 ± 10 years, with 442 (69%) males and 328 (51%) patients with paroxysmal AF equally distributed between the 2 groups. Patients in the warfarin group had a slightly higher mean HAS- BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly, drugs/alcohol concomitantly) score (1.70 ± 1.0 vs. 1.47 ± 0.9, respectively; p = 0.032). Bleeding and embolic complications occurred in 47 (7.3%) and 2 (0.3%) patients (both had transient ischemic attacks) respectively. There were no differences in the number of major bleeding complications (5 [1.6%] vs. 7 [1.9%], respectively; p = 0.772), minor bleeding complications (16 [5.0%] vs. 19 [5.9%], respectively; p = 0.602), or embolic complications (1 [0.3%] vs. 1 [0.3%], respectively; p = 1.0) between the rivaroxaban and warfarin groups in the first 30 days. Conclusions Uninterrupted rivaroxaban therapy appears to be as safe and efficacious in preventing bleeding and thromboembolic events in patients undergoing AF ablation as uninterrupted warfarin therapy.