Retrograde coronary venous ethanol ablation for ventricular tachycardia in a patient with inaccessible substrate due to previous surgery.

INTRODUCTION: Catheter-based radiofrequency (RF) ablation is generally regarded as the standard approach for patients with ventricular tachycardia (VT) refractory to antiarrhythmic drug therapy and may be considered as a first-line approach when there is a preference to avoid these agents. Patients with a history of cardiac surgery may have VT substrate inaccessible to catheter ablation due to intervening prosthetic materials or scar. METHODS AND RESULTS: This article describes a 55-year-old patient with a history of surgically repaired subvalvular aortic stenosis and subsequent valve-sparing root replacement who presented with sustained VT. After RF ablation failed due to VT substrate "guarded" by graft material, retrograde coronary venous ethanol ablation (RCVEA) was employed to successfully treat the clinical VT. CONCLUSION: RCVEA ablation can be useful for treating VT when conventional ablation is limited by inaccessible substrate due to prior cardiac surgery.

Utility of noninvasive electrocardiographic imaging in the localization of nonpulmonary vein triggers of atrial fibrillation determined by pacing common trigger sites.

INTRODUCTION: Identifying the origin of nonpulmonary vein atrial fibrillation (AF) triggers (NPVTs) after pulmonary vein isolation (PVI) can be challenging. We aimed to determine if noninvasive electrocardiographic imaging (ECGi) could localize pacing from common NPVT sites. ECGi combines measured body surface potentials with heart-torso geometry acquired from computed tomography (CT) to generate an activation map. METHODS: In 12 patients with AF undergoing first time ablation, the ECGi vest was fitted for preprocedural CT scan and worn during the procedure. After PVI, we performed steady-state pacing from 15 typical anatomic NPVT sites at a cycle length of 700-800 ms. We co-registered the invasive anatomic map with the CT-based ECGi epicardial activation map to compare ECGi predicted to true pacing origin. RESULTS: In the study cohort (67% male, 58% persistent AF, and 67% with left atrial dilation), 148 (82%) pacing sites had both capture and adequate anatomy acquired from the three-dimensional mapping system to co-register with ECGi activation map. Median distance between true pacing sites and point of earliest epicardial activation derived from the ECGi maps for all sites was 17 mm (interquartile range, 10-22 mm). Assuming paced sites treated as regions with a radius of 2.5 cm, the earliest activation site on ECGi map falls within the region with 94% accuracy. CONCLUSION: ECGi can approximate the origin of paced beats from common NPVT sites to within a median distance of 17 mm. A rapidly identified region may then be the focus of more detailed catheter-based mapping techniques to facilitate successful localization and ablation of NPVTs.

Dronedarone treatment following cardioversion in patients with atrial fibrillation/flutter: A post hoc analysis of the EURIDIS and ADONIS trials.

INTRODUCTION: The phase 3 EURIDIS and ADONIS studies evaluated dronedarone for atrial fibrillation (AF)/atrial flutter (AFL) recurrence in patients with nonpermanent AF. Here we assessed whether patient characteristics and/or treatment outcomes in these studies differed based on the need for cardioversion before randomization. METHODS: Time to adjudicated first AF/AFL recurrence, symptomatic recurrence, cardiovascular hospitalization/death, and AF hospitalization, and safety were assessed by cardioversion status. RESULTS: Of 1237 patients randomized (2:1 dronedarone:placebo), 364 required baseline cardioversion (dronedarone 243, placebo 121). Patients requiring cardioversion had a greater prevalence of cardiovascular comorbidities and shorter times to first AF/AFL recurrence compared with those not requiring cardioversion. Dronedarone was associated with longer median time to first AF/AFL recurrence vs placebo regardless of cardioversion status (cardioversion: 50 vs 15 days, hazard ratio [HR] 0.76; 95% confidence interval [CI], 0.59-0.97; P = .02; non-cardioversion: 150 vs 77 days, HR 0.76; 95% CI, 0.64-0.90; P < .01). Dronedarone was similarly associated with prolonged median time to symptomatic recurrence vs placebo in the cardioversion (347 vs 87 days, HR 0.65; 95% CI, 0.49-0.87) and non-cardioversion (288 vs 120 days, HR 0.74; 95% CI, 0.62-0.90) populations. Risk of cardiovascular hospitalization/death and first AF hospitalization was lower with dronedarone vs placebo regardless of cardioversion status, but differences were not statistically significant. The safety of dronedarone was similar in both groups. CONCLUSION: Patients requiring baseline cardioversion represent a distinct population, having more underlying cardiovascular disease and experiencing a shorter time to AF/AFL recurrences. Dronedarone was associated with improved efficacy vs placebo regardless of cardioversion status.

Two- and Three-dimensional Transthoracic Echocardiographic Assessment of Tricuspid Valve Prolapse with Mid-to-Late Systolic Tricuspid Regurgitation.

We present the two-dimensional echocardiographic findings of tricuspid valve prolapse with mid-to-late systolic tricuspid regurgitation and describe the incremental value provided by live/real time three-dimensional transthoracic echocardiography. We also discuss a potential pitfall when assessing the severity of regurgitation in this setting.

Incremental value of live/real time three-dimensional transthoracic echocardiography over two-dimensional echocardiography in hypertrophic cardiomyopathy with mid-ventricular obstruction and apical aneurysm.

We describe a case of hypertrophic cardiomyopathy with mid-left ventricular obstruction and apical aneurysm containing thrombi where live/real time three-dimensional transthoracic echocardiography provided incremental value over two-dimensional echocardiography in assessing the findings.

Incremental value of live/real time three-dimensional transesophageal echocardiography over the two-dimensional modality in the assessment of cardiac lymphoma.

We describe a case of cardiac lymphoma where live/real time three-dimensional transesophageal echocardiography provided additional information compared to two-dimensional transesophageal echocardiography regarding the extent of tumor infiltration. In addition, it gave a quantitative assessment of the tumor burden by providing its volume.

Incremental value of live/real time three-dimensional transesophageal echocardiography over the two-dimensional technique in the assessment of primary cardiac malignant fibrous histiocytoma.

We describe a case of primary cardiac malignant fibrous histiocytoma where live/real time three-dimensional transesophageal echocardiography added incremental value to the two-dimensional modalities. Specifically, the three-dimensional technique allowed us to delineate the true extent and infiltration of the tumor, to identify characteristics of the tumor mass suggestive of its malignant nature, and to quantitatively assess the total tumor burden.

Incremental Value of Three-Dimensional Transesophageal Echocardiography over the Two-Dimensional Technique in the Assessment of a Thrombus in Transit through a Patent Foramen Ovale.

We report a case of a right atrial thrombus traversing a patent foramen ovale into the left atrium, where three-dimensional transesophageal echocardiography provided considerable incremental value over two-dimensional transesophageal echocardiography in its assessment. As well as allowing us to better spatially characterize the thrombus, three-dimensional transesophageal echocardiography provided a more quantitative assessment through estimation of total thrombus burden.

Predictors of nonpulmonary vein triggers for atrial fibrillation: A clinical risk score.

BACKGROUND: Targeting non-pulmonary vein triggers (NPVTs) after pulmonary vein isolation may reduce atrial fibrillation (AF) recurrence. Isoproterenol infusion and cardioversion of spontaneous or induced AF can provoke NPVTs but typically require vasopressor support and increased procedural time. OBJECTIVE: The purpose of this study was to identify risk factors for the presence of NPVTs and create a risk score to identify higher-risk subgroups. METHODS: Using the AF ablation registry at the Hospital of the University of Pennsylvania, we included consecutive patients who underwent AF ablation between January 2021 and December 2022. We excluded patients who did not receive NPVT provocation testing after failing to demonstrate spontaneous NPVTs. NPVTs were defined as non-pulmonary vein ectopic beats triggering AF or focal atrial tachycardia. We used risk factors associated with NPVTs with P <.1 in multivariable logistic regression model to create a risk score in a randomly split derivation set (80%) and tested its predictive accuracy in the validation set (20%). RESULTS: In 1530 AF ablations included, NPVTs were observed in 235 (15.4%). In the derivation set, female sex (odds ratio [OR] 1.40; 95% confidence interval [CI] 0.96-2.03; P = .080), sinus node dysfunction (OR 1.67; 95% CI 0.98-2.87; P = .060), previous AF ablation (OR 2.50; 95% CI 1.70-3.65; P <.001), and left atrial scar (OR 2.90; 95% CI 1.94-4.36; P <.001) were risk factors associated with NPVTs. The risk score created from these risk factors (PRE2SSS2 score; [PRE]vious ablation: 2 points, female [S]ex: 1 point, [S]inus node dysfunction: 1 point, left atrial [S]car: 2 points) had good predictive accuracy in the validation cohort (area under the receiver operating characteristic curve 0.728; 95% CI 0.648-0.807). CONCLUSION: A risk score incorporating predictors for NPVTs may allow provocation of triggers to be performed in patients with greatest expected yield.

Sinus rhythm electrocardiographic abnormalities, sites of origin, and ablation outcomes of ventricular premature depolarizations initiating ventricular fibrillation.

BACKGROUND: Ventricular fibrillation (VF) can be initiated by ventricular premature depolarizations (VPDs) in the absence of obvious structural abnormalities. OBJECTIVE: The purpose of this study was to determine the prevalence of 12-lead electrocardiographic (ECG) sinus rhythm reduced QRS amplitude, QRS fractionation (QRSf), and early repolarization (ER) pattern, and the outcome of catheter ablation and VPD anatomic distribution in patients with VPDs initiating VF. METHODS: We compared a cohort with no apparent structural heart disease and VPDs initiating VF (group 1; n = 42) to a reference cohort (group 2; n = 61) of patients with no structural heart disease and symptomatic unifocal VPDs. RESULTS: A reduced QRS amplitude (<0.55 mV) in aVF (59% vs 10%; P <.001), QRSf in ≥2 contiguous leads (50% vs 16%; P <.001), and ER pattern (21.4% vs 1.6%; P = .01) were more common in group 1 than in group 2. At least 1 abnormal ECG finding was present in 34 group 1 patients (81%) vs 17 group 2 patients (28%) (P <.001). VPD origin included right ventricular and left ventricular distal Purkinje system and moderator band/papillary muscles in 83% of group 1 patients vs 18% of group 2 patients (P <.001). VF was eliminated with a single ablation procedure in 77% of group 1 patients with at least 2 years of follow-up. CONCLUSION: A reduced QRS amplitude (<0.55 mV) in aVF, QRSf in ≥2 contiguous leads, and/or an ER pattern are frequently observed in patients with VPDs initiating VF. VPDs initiating VF typically originate from the distal Purkinje system and papillary muscles and can be successfully eliminated with catheter ablation.

Septal Substrate Ablation Guided by Delayed Transmural Conduction Times: A Novel Ablation Approach to Target Intramural Substrates.

BACKGROUND: Intraprocedural identification of intramural septal substrate for ventricular tachycardia (ISS-VT) in nonischemic cardiomyopathy (NICM) is challenging. Delayed (>40 ms) transmural conduction time (DCT) with right ventricular basal septal pacing has been previously shown to identify ISS-VT. OBJECTIVES: This study sought to determine whether substrate catheter ablation incorporating areas of DCT may improve acute and long-term outcomes. METHODS: We included patients with NICM and ISS-VT referred for catheter ablation between 2016 and 2020. ISS-VT was defined by the following: 1) confluent septal areas of low unipolar voltage (<8.3 mV) in the presence of normal or minimal bipolar abnormalities; and 2) presence of abnormal electrograms in the septum. Substrate ablation was guided by the following: 1) activation and/or entrainment mapping for tolerated VT and pace mapping with ablation of abnormal septal electrograms for unmappable VTs (n = 57, Group 1); and 2) empirically extended to target areas of DCT during right ventricular basal septal pacing regardless of their participation in inducible VT(s) but sparing the conduction system when possible (n = 24, Group 2). RESULTS: There were no significant baseline differences between Groups 1 and 2. Noninducibility of any VT programmed stimulation at the end of ablation was higher in Group 2 compared with Group 1 (80% vs 53%; P = 0.03). At 12-month follow-up, single-procedure VT-free survival was significantly higher (79% vs 46%; P = 0.006) and the time to VT recurrence was longer (mean 10 ± 3 months vs 7 ± 4 months; P = 0.02) in Group 2 compared with Group 1. CONCLUSIONS: In patients with NICM and ISS-VT, a substrate ablation strategy that incorporates areas of DCT appears to improve freedom from recurrent VT.

Identifying Origin of Nonpulmonary Vein Triggers Using 2 Stationary Linear Decapolar Catheters: A Novel Algorithm.

BACKGROUND: Targeting nonpulmonary vein triggers (NPVTs) of atrial fibrillation (AF) after pulmonary vein isolation can be challenging. NPVTs are often single ectopic beats with a surface P-wave obscured by a QRS or T-wave. OBJECTIVES: The goal of this study was to construct an algorithm to regionalize the site of origin of NPVTs using only intracardiac bipolar electrograms from 2 linear decapolar catheters positioned in the posterolateral right atrium (along the crista terminalis with the distal bipole pair in the superior vena cava) and in the proximal coronary sinus (CS). METHODS: After pulmonary vein isolation in 42 patients with AF, pacing from 15 typical anatomic NPVT sites was conducted. For each pacing site, the electrogram activation sequence was analyzed from the CS catheter (simultaneous/chevron/inverse chevron/distal-proximal/proximal-distal) and activation time (ie, CSCTAT) between the earliest electrograms from the 2 decapolar catheters was measured referencing the earliest CS electrogram; a negative CSCTAT value indicates the crista terminalis catheter electrogram was earlier, and a positive CSCTAT value indicates the CS catheter electrogram was earlier. A regionalization algorithm with high predictive value was defined and tested in a validation cohort with AF NPVTs localized with electroanatomic mapping. RESULTS: In the study patient cohort (71% male; 43% with persistent AF, 52% with left atrial dilation), the algorithm grouped with high precision (positive predictive value 81%-99%, specificity 94%-100%, and sensitivity 30%-94%) the 15 distinct pacing sites into 9 clinically useful regions. Algorithm testing in a 98 patient validation cohort showed predictive accuracy of 91%. CONCLUSIONS: An algorithm defined by the activation sequence and timing of electrograms from 2 linear multipolar catheters provided accurate regionalization of AF NPVTs to guide focused detailed mapping.

Predictors of dronedarone plasma drug concentrations and effect on atrial fibrillation/atrial flutter recurrence: Analyses from the EURIDIS and ADONIS studies.

BACKGROUND: In this post hoc analysis, we assessed patient characteristics as predictors of dronedarone trough concentrations and characterized the relationship of trough concentrations of dronedarone with its efficacy and safety. HYPOTHESIS: Dronedarone is recommended as a 400 mg twice daily dose taken orally with meals. We hypothesize that drug concentration/bioavailability of dronedarone, measured as above- and below-median trough concentrations, does not impact the efficacy outcomes. METHODS: Average trough concentrations (Ctrough_avg ) across multiple timepoints were calculated for each patient, and patient Ctrough_avg values were categorized as below-median or above-median concentrations. The effect of patient baseline characteristics on dronedarone Ctrough_avg was assessed in the below-median versus above-median groups. The effect of dronedarone in each Ctrough_avg group versus placebo on risk of first atrial fibrillation/atrial flutter (AF/AFL) recurrence and safety was also evaluated. RESULTS: Overall, 1795 plasma samples were available from 507 dronedarone-treated patients. An above-median Ctrough_avg was associated with age ≥75 years, female sex, lower weight, higher pacemaker use, and higher oral anticoagulant use. The risk of adjudicated first AF/AFL recurrence was significantly lower with dronedarone versus placebo in the below-median (hazard ratio [HR]: 0.71; 95% confidence interval [CI]: 0.56-0.91; p = .0054) and above-median groups (HR: 0.63; 95% CI: 0.50-0.81; p = .0002). No difference in risk of AF/AFL recurrence was observed between the above- and below-median groups. Safety and tolerability of dronedarone were similar between groups. CONCLUSION: Significant reduction in AF/AFL recurrence was observed in patients treated with dronedarone versus placebo, regardless of dronedarone concentrations above or below the median value.

Impact of dronedarone on patients with atrial fibrillation and diabetes: A sub-analysis of the ATHENA and EURIDIS/ADONIS studies.

AIM: This post hoc analysis evaluated efficacy and safety of dronedarone in atrial fibrillation (AF) and atrial flutter (AFL) patients with/without diabetes. METHODS: Patients were categorized according to baseline diabetes status. Time-to-event analyses were performed using Kaplan-Meier method. Hazard-ratios were assessed using Cox models. RESULTS: 945/4628 (dronedarone = 482; placebo = 463) patients in ATHENA and 215/1237 (dronedarone = 148; placebo = 67) patients in EURIDIS/ADONIS studies had diabetes. In ATHENA, there were higher rates of CV hospitalization/death in patients with diabetes (39.5%) than without diabetes (34.7%). Incidence of first CV hospitalization/death was lower in patients with diabetes treated with dronedarone (35.1%) than placebo (44.1%), and time to this event was longer in those treated with dronedarone than placebo (log-rank p = 0.005). Median AF/AFL recurrence time was longer in patients treated with dronedarone than placebo in patients with diabetes (ATHENA: 722 vs 527 days, log-rank p = 0.004; EURIDIS/ADONIS: 100 vs 23 days, log-rank p = 0.15) or without diabetes (ATHENA: 741 vs 492 days, log-rank p < 0.0001; EURIDIS/ADONIS: 120 vs 59 days, log-rank p = 0.0002). Occurrence of any treatment-related adverse events with dronedarone was similar for patients with/without diabetes and was comparable to placebo. CONCLUSIONS: Dronedarone reduced incidence of CV hospitalization/death, AF/AFL recurrence and increased time to these events in AF/AFL patients with/without diabetes. TRIAL REGISTRATION: Not applicable, as it was a post hoc analysis. This article is based on previously conducted studies (ATHENA: NCT00174785, EURIDIS: NCT00259428, and ADONIS: NCT00259376).

Efficacy and safety of dronedarone versus placebo in patients with atrial fibrillation stratified according to renal function: Post hoc analyses of the EURIDIS-ADONIS trials.

BACKGROUND: The use of antiarrhythmic drugs (AADs) in patients with chronic kidney disease (CKD) is complex because impaired renal clearance can cause increased drug levels, and risk of intolerance or adverse events. Due to the propensity for CKD to occur alongside atrial fibrillation/atrial flutter (AF/AFL), it is essential that AAD safety and efficacy are assessed for patients with CKD. HYPOTHESIS: Dronedarone, an approved AAD, may present a suitable therapeutic option for patients with AF/AFL and concomitant CKD. METHODS: EURIDIS-ADONIS (EURIDIS, NCT00259428; ADONIS, NCT00259376) were identically designed, multicenter, double-blind, parallel-group trials investigating AF/AFL control with dronedarone 400 mg twice daily versus placebo (randomized 2:1). In this post hoc analysis, the primary endpoint was time to first AF/AFL. Patients were stratified according to renal function using the CKD-Epidemiology Collaboration equation and divided into estimated glomerular filtration rate (eGFR) subgroups of 30-44, 45-59, 60-89, and ≥90 ml/min. Time-to-events between treatment groups were compared using log-rank testing and Cox regression. RESULTS: At baseline, most (86%) patients demonstrated a mild or mild-to-moderate eGFR decrease. Median time to first AF/AFL recurrence was significantly longer with dronedarone versus placebo for all eGFR subgroups except the 30 to 44 ml/min group, where the trend was similar but statistical power may have been limited by the small population. eGFR stratification had no significant effect on serious adverse events, deaths, or treatment discontinuations. CONCLUSIONS: This analysis suggests that dronedarone could be an effective therapeutic option for AF with an acceptable safety profile in patients with impaired renal function.

The Role of the Food and Drug Administration in Drug Development: On the Subject of Proarrhythmia Risk.

The Food and Drug Administration (FDA) is responsible for the regulation of the pharmaceutical industry in the interest of protecting public health. The aim of this review was to outline the evolution and current role of the FDA in the development and approval of new drugs. Additionally, we describe current assessments of proarrhythmia risk to illustrate recent FDA initiatives intended to harness information technology to modernize the regulatory process. In order to identify the literature required to produce this review, search tools such as PubMed and Google Scholar were used to locate relevant web pages and articles. The job of the FDA is not only to ensure that high standards for drug efficacy and safety are applied to products available to American consumers and patients but also to balance the lengthy, costly process of maintaining these standards against the pressure to provide access to effective treatments earlier and without surplus expenditures. In order to provide expedited access to the newest effective therapies for critically ill patients in the safest way possible, the FDA has developed several accelerated pathways to fast-track drug approval. Through partnerships with industry and academic institutions, research is being conducted into how information technology can be integrated into the drug development process to improve its cost-effectiveness.

How to Prescribe Drugs With an Identified Proarrhythmic Liability.

This is an article in the Journal of Clinical Pharmacology's Core Entrustable Professional Activities in Clinical Pharmacology series that discusses drug-induced proarrhythmia and is offered as a teaching aid for medical students and residents. Drugs from diverse pharmacological classes can lead to multiple types of arrhythmias including the polymorphic ventricular tachycardia torsades de pointes (TdP). Although typically occurring in self-limiting bursts with or without associated symptoms, which can range from mild lightheadedness and palpitations to syncope and seizures, TdP can also occasionally progress to ventricular fibrillation and sudden cardiac death. To provide patients with the optimal therapeutic benefits of potentially proarrhythmic drugs, prescribers are responsible for obtaining a good understanding of the compound's benefit-risk properties and perform a judicious assessment of the patient's clinical characteristics and individual risk factors. Dose adjustments and/or additional monitoring of electrocardiograms and electrolyte balances may be appropriate in some cases. This article explains the pharmacological mechanism of action of drug-induced proarrhythmia associated with compounds that prolong the repolarization period, illustrates how this liability is conveyed in a drug's prescribing information (label), details the clinical characteristics of patients most susceptible to this type of proarrhythmia, and describes interventions that can be made if TdP occurs. Three clinical vignettes are provided at the end of the article to highlight the relevance of the preceding discussions.

Bretylium, a Class III Antiarrhythmic, Returns to the Market.

Bretylium, with an extensive pharmacologic and medicinal history, was approved by the United States Food and Drug Administration in 1986 for "short-term prevention and treatment of ventricular fibrillation (VF) and treatment of life-threatening ventricular arrhythmias and ventricular tachycardia (VT) unresponsive to adequate doses of a first-line antiarrhythmic agent, such as lidocaine." The NDA sponsor withdrew bretylium from the market in 2011, largely due to unavailability of raw materials required for its production; prior to this, bretylium was removed from the 2000 ACLS Guidelines algorithm for VF/pulseless VT given the challenges obtaining raw materials for drug manufacture. Recently, bretylium has been reintroduced into the US market by a generic pharmaceutical company with the same indications as before. This article provides a history of the salient trials evaluating the efficacy and safety of bretylium and looks to the future as bretylium finds its place in the modern day management of ventricular arrhythmia.

Cardiovascular Complications of Marijuana and Related Substances: A Review.

The recreational use of cannabis has sharply increased in recent years in parallel with its legalization and decriminalization in several countries. Commonly, the traditional cannabis has been replaced by potent synthetic cannabinoids and cannabimimetics in various forms. Despite overwhelming public perception of the safety of these substances, an increasing number of serious cardiovascular adverse events have been reported in temporal relation to recreational cannabis use. These have included sudden cardiac death, vascular (coronary, cerebral and peripheral) events, arrhythmias and stress cardiomyopathy among others. Many of the victims of these events are relatively young men with few if any cardiovascular risk factors. However, there are reasons to believe that older individuals and those with risk factors for or established cardiovascular disease are at even higher danger of such events following exposure to cannabis. The pathophysiological basis of these events is not fully understood and likely encompasses a complex interaction between the active ingredients (particularly the major cannabinoid, Δ9-tetrahydrocannabinol), and the endo-cannabinoid system, autonomic nervous system, as well as other receptor and non-receptor mediated pathways. Other complicating factors include opposing physiologic effects of other cannabinoids (predominantly cannabidiol), presence of regulatory proteins that act as metabolizing enzymes, binding molecules, or ligands, as well as functional polymorphisms of target receptors. Tolerance to the effects of cannabis may also develop on repeated exposures at least in part due to receptor downregulation or desensitization. Moreover, effects of cannabis may be enhanced or altered by concomitant use of other illicit drugs or medications used for treatment of established cardiovascular diseases. Regardless of these considerations, it is expected that the current cannabis epidemic would add significantly to the universal burden of cardiovascular diseases.

Embolic and Other Adverse Outcomes in Symptomatic Versus Asymptomatic Patients With Atrial Fibrillation (from the ORBIT-AF Registry).

Asymptomatic atrial fibrillation (AF) is being increasingly diagnosed via implantable devices, screening, and inpatient telemetry. Management of asymptomatic AF is controversial, in part, because the associated risks have not been well described. We examined the incidence of major adverse outcomes in patients with asymptomatic versus symptomatic AF using Outcomes Registry for Better Informed Treatment of Atrial, a nationwide US registry of AF patients. We compared stroke and/or non-central nervous system (CNS) embolism, major adverse cardiovascular and neurologic events, bleeding, and death in 9,319 asymptomatic (defined by European Heart Rhythm Association score = 1 or "no symptoms") versus symptomatic patients. Overall, median (interquartile) age was 75 (67 to 82) years, 3,944 (42%) were women, and 38% versus 37% were asymptomatic based on physician versus patient-reported symptoms. Compared with those with symptoms, physician-defined asymptomatic patients were less likely to be woman (35%/47%) or be on an antiarrhythmic agent (22%/33%), but were more likely to have permanent and/or persistent AF (51%/40%). CHA2DS2-VASc scores did not vary by symptom status. After adjustment, risk of first stroke and/or non-CNS embolism (hazard ratio [HR] 0.85 [95% confidence interval {CI} 0.63 to 1.16], p = 0.32), major adverse cardiovascular and neurologic events (HR 0.88 [95% CI 0.76 to 1.03], p = 0.11), bleeding (HR 0.85 [95% CI 0.72 to 1.00], p = 0.05), and death (HR 0.99 [95% CI 0.87 to 1.13], p = 0.88) were similar in asymptomatic (European Heart Rhythm Association = 1) and symptomatic AF, respectively. Prospective, randomized studies are needed to further define associated adverse events and delineate optimal prophylactic therapies in patients with asymptomatic AF.