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Background: Percutaneous endocardial left atrial appendage occlusion (LAAO) is an alternative therapy for stroke prevention in patients with atrial fibrillation who are poor candidates for oral anticoagulants. Oral anticoagulation is generally discontinued 45 days following successful LAAO. Real-world data on early stroke and mortality following LAAO are lacking. Methods: Using International Classification of Diseases, Tenth Revision , Clinical-Modification codes, we performed a retrospective observational registry analysis to examine the rates and predictors of stroke, mortality, and procedural complications during index hospitalization and 90-day readmission among 42 114 admissions in the Nationwide Readmissions Database for LAAO between 2016 and 2019. Early stroke and mortality were defined as events occurring during index admission or 90-day readmission. Data on timing of early strokes post-LAAO were collected. Multivariable logistic regression modeling was used to ascertain predictors of early stroke and major adverse events. Results: LAAO was associated with low rates of early stroke (0.63%), early mortality (0.53%), and procedural complications (2.59%). Among patients who had readmissions with strokes after LAAO, the median time from implant to readmission was 35 days (interquartile range, 9–57 days); 67% of readmissions with strokes occurred P -for-trend Conclusions: In this contemporary real-world analysis, the early stroke rate after LAAO was low, with the majority occurring within 45 days of device implantation. Despite an increase in LAAO procedures between 2016 and 2019, there with a significant decline in early strokes after LAAO during that period.

Background Electrocardiographic (ECG) criteria have been proposed to localize the site of origin of outflow region ventricular arrhythmias (VAs). Many factors influence the QRS morphology of VAs and may limit the accuracy of these criteria. Objective The purpose of this study was to assess the accuracy of ECG criteria that differentiate right from left outflow region VAs and localize VAs within the aortic sinus of Valsalva (ASV). Methods One hundred one patients (mean age 52 ± 16 years; 55 [54%] women) undergoing catheter ablation of right ventricular outflow tract (RVOT) or ASV VAs with a left bundle branch block, inferior axis morphology were studied. ECG measurements including V2 transition ratio, transition zone index, R-wave duration index, R/S amplitude index, V2S/V3R index, V1–3 QRS morphology, R-wave amplitude in the inferior leads were tabulated for all VAs. Comparisons were made between the predicted site of origin using these criteria and the successful ablation site. Results Patients had successful ablation of 71 RVOT and 38 ASV VAs. For the differentiation of RVOT from ASV VAs, the positive predictive values and negative predictive values for all tested ECG criteria ranged from 42% to 75% and from 71% to 82%, respectively, with the V2S/V3R index having the largest area under the curve of 0.852. Morphological QRS criteria in leads V1 through V3 did not localize ASV VAs. The maximum R-wave amplitude in the inferior leads was the sole criterion demonstrating a significant difference between right ASV, right-left ASV commissure, and left ASV sites. Conclusion ECG criteria for differentiating right from left ventricular outflow region VAs and for localizing ASV VAs have a limited accuracy.

Left bundle branch area pacing (LBBP) has emerged as an alternative method for conduction system pacing. While initial experience with delivery systems allowing lumenless and stylet-driven lead implantation for LBBP has been described, data comparing outcomes of stylet-driven versus lumenless lead implantation for LBBP are limited. In this study, we compare success rates and outcomes of LBBP with stylet-driven versus lumenless lead delivery systems.Eighty-three consecutive patients (mean age 74.1 ± 11.2 years; 56 (68%) male) undergoing attempted LBBP at a single institution were identified. Cases were grouped by lead delivery systems used: stylet-driven (n = 53) or lumenless (n = 30). Baseline characteristics and procedural findings were recorded and compared between the cohorts. Medium term follow-up data on ventricular lead parameters were also compared.Baseline characteristics were similar between groups. Successful LBBP was achieved in 77% of patients, with similar success rates between groups (76% in stylet-driven, 80% in lumenless, p = 0.79), and rates of adjudicated LBB capture and other paced QRS parameters were also similar. Compared with the lumenless group, the stylet-driven group had significantly shorter procedure times (90 ± 4 vs 112 ± 31 min, p = 0.004) and fluoroscopy times (10 ± 5 vs 15 ± 6 min, p = 0.003). Ventricular lead parameters at medium term follow-up were similar, and rates of procedural complications and need for lead revision were low in both groups.Delivery systems for stylet-driven and for lumenless leads for LBBP have comparable acute success rates. Long-term follow-up of lead performance following use of the various delivery systems is warranted. This article is protected by copyright. All rights reserved.

INTRODUCTION The real-world distribution of hospital atrial fibrillation (AF) ablation volume and its impact on outcomes are not well-established. We sought to examine patient characteristics, complications, and readmissions after AF ablation stratified by hospital procedural volume. METHODS AND RESULTS Using the nationally representative inpatient Nationwide Readmissions Database, we evaluated 54 597 admissions for AF ablation between 2010 and 2014. Hospitals were categorized according to tertiles of annual AF ablation volume. Index complications, 30-day readmissions, and early mortality were examined. Multivariable logistic regression was performed to assess the predictors of adverse outcomes. Between 2010 and 2014, low volume tertile hospitals accounted for 79.3% of hospitals performing AF ablations. When stratified by first, second, and third volume tertiles, complication and early mortality rates were higher in low volume centers (8.9% and 0.67% vs 6.1% and 0.33%, vs 4.5% and 0.16%, respectively; P

Robotic technology has emerged as an important tool to facilitate catheter ablation of arrhythmias. Robotic cardiac electrophysiology technology includes remote magnetic navigation and manual robotic navigation. Robotics can confer advantages with respect to ease of catheter manipulation in anatomically challenging spaces, minimization of fluoroscopic exposure to both patients and operators, and reduction in operator fatigue. This review provides a comprehensive summary of robotic electrophysiology technology, its practical applications and its safety and efficacy for targeting cardiac arrhythmias.

Limited real-world data exist on early outcomes in patients with heart failure with preserved ejection fraction (HFpEF) undergoing atrial fibrillation (AF) ablation.The purpose of this study was to examine and compare rates of index procedural complications and 30-day readmissions after AF ablation in patients with HFpEF, with heart failure with reduced ejection fraction (HFrEF), and without heart failure.Using the Nationwide Readmissions Database (NRD), we examined 50,299 admissions of adults with heart failure undergoing AF catheter ablation between 2010 and 2014. Using ICD-9-CM codes, we identified procedural complications and causes of readmission after AF ablation.From 2010 to 2014, the prevalence of HFpEF among patients undergoing AF ablation increased from 3.05% to 7.35% (Rates of 30-day readmissions after AF ablation are high in patients with HFpEF. However, after adjustment for age and comorbidities, complications and early mortality after AF ablation between patients with HFpEF and those without heart failure are comparable.

Introduction: Atypical atrial flutter (aAFL) has been described in the absence of prior atrial interventions, but prognosis for these patients after catheter ablation is poorly defined. This study was designed to define characteristics and ablation outcomes in patients with de novo aAFL. Methods: Patients with non-CTI flutter, without prior ablation or cardiac surgery, were identified from an institutional database. Clinical, mapping, ablation, and follow up data were compared to an equally sized group of randomly selected patients with typical flutter (tAFL). Results: The 35 patients with aAFL had 45 mapped non-CTI flutters. aAFL patients had similar age, gender, cardiovascular comorbidities, and LA size compared to tAFL, except aAFL patients had higher LVEF (54 ± 12 vs 46 ± 19%, p=0.04). Cycle length of aAFL was longer (268 [IQR 231, 310] vs 230 [220, 250] msec, p=0.0006). aAFL localized to the RA in 16, LA in 28, and biatrial in 1. Mechanisms were macroreentry in 23 (8 RA, 15 LA) and localized reentry in 22 (8 RA, 14 LA). Areas of scar predominated in the lateral/posterior RA (N=9), anterior LA (N=14), and posterior LA (N=6). Most common LA circuits were perimitral reentry (N=8) and roof dependent (N=8), including dual loop reentry. Localized reentry occurred most commonly in the anterior LA (N=7) or involved the pulmonary veins (N=4). Ablation was acutely successful for 41/45 aAFLs (91%) and for all tAFL. After median follow-up of 33 [6.6, 55] mo, atrial arrhythmias recurred in 23/34 aAFL patients (68%) and 24/35 tAFL patients (69%); those with aAFL had earlier recurrences (1.9 [0.43, 11] vs 19 [2.3, 36] mo, p=0.01). First recurrences after aAFL ablation were more likely to be AFL rather than AF (83% vs 17%) whereas tAFL patients were more likely to recur with AF (24% AFL vs 76% AF, p Conclusions: Patients with de novo aAFL tend to have spontaneous scar, commonly in the lateral/posterior RA and anterior LA, consistent with an atrial myopathy. Ablation can be accomplished with high acute success, but recurrent atrial arrhythmias are common, most re-presenting with atrial tachycardias. Future studies should clarify if a substrate-based approach or adjunctive antiarrhythmic drugs would result in better long term outcomes.

Although procedure-related deaths during index admission following catheter ablation of AF have been reported to be low, adverse outcomes can occur after discharge. There are limited data on mortality early after AF ablation.This study aimed to identify rates, trends, and predictors of early mortality post-atrial fibrillation (AF) ablation.Using the all-payer, nationally representative Nationwide Readmissions Database, we evaluated 60,203 admissions of patients 18 years of age or older for AF ablation between 2010 and 2015. Early mortality was defined as death during initial admission or 30-day readmission. Based on International Classification of Diseases-9th Revision, Clinical Modification codes, we identified comorbidities, procedural complications, and causes of readmission following AF ablation. Multivariable logistic regression was performed to assess predictors of early mortality.Early mortality following AF ablation occurred in 0.46% cases, with 54.3% of deaths occurring during readmission. From 2010 to 2015, quarterly rates of early mortality post-ablation increased from 0.25% to 1.35% (p 0.001). Median time from ablation to death was 11.6 (interquartile range [IQR]: 4.2 to 22.7) days. After adjustment for age and comorbidities, procedural complications (adjusted odds ratio [aOR]: 4.06; p 0.001), congestive heart failure (CHF) (aOR: 2.20; p = 0.011) and low AF ablation hospital volume (aOR: 2.35; p = 0.003) were associated with early mortality. Complications due to cardiac perforation (aOR: 2.98; p = 0.007), other cardiac (aOR: 12.8; p 0.001), and neurologic etiologies (aOR: 8.72; p 0.001) were also associated with early mortality.In a nationally representative cohort, early mortality following AF ablation affected nearly 1 in 200 patients, with the majority of deaths occurring during 30-day readmission. Procedural complications, congestive heart failure, and low hospital AF ablation volume were predictors of early mortality. Prompt management of post-procedure complications and CHF may be critical for reducing mortality rates following AF ablation.

Premature ventricular contractions (PVCs) are a common arrhythmia that may cause symptoms of variable severity. PVCs have recently garnered interest in their ability to induce adverse structural heart remodeling in an entity known as PVC-induced cardiomyopathy. This entity is a retrospective diagnosis that likely remains under-recognized and may occur concurrently with other forms of cardiomyopathy. The appropriate identification and management of PVCs in the setting of associated cardiomyopathy may have a significant impact on cardiac function and the clinical course, including recovery of left ventricular ejection fraction and improvement in patient functional status. Treatment consists of catheter ablation and/or antiarrhythmic drug therapy, but continued monitoring and follow-up are required, as the recurrence of high PVC burden may lead to redevelopment of cardiomyopathy.

Left atrial tachycardias (ATs) most commonly occur after catheter or surgical ablation of atrial fibrillation and in patients with atrial myopathies. Pre-existing scar in the left atrium (LA) can result in complex circuits, sometimes with narrow channels that can be detected with high-resolution mapping. The most common forms of macroreentrant AT from the LA are variants of peri-mitral and roof-dependent reentry. Localized reentrant rhythms occur in the setting of fibrosis that gives rise to slow conduction and may occur adjacent to areas of prior ablation. The approach to treating these ATs involves first identifying the left atrial origin, defining the tachycardia circuit - which can be facilitated by ultrahigh density mapping and entrainment - and selecting a suitable isthmus to target for ablation. An important endpoint in ablating left atrial flutters is to establish and confirm bidirectional line of the block. Challenges in ablating these ATs include the presence of multiple tachycardias, defining circuits with complex activation patterns and achieving durable lines of block, particularly in the lateral mitral isthmus. Progress in treating these arrhythmias has come from new mapping technologies and the recognition of epicardial connections that allow for persistent conduction across ablation lesions. Also, advances in delivering energy to obtain complete transmural lesions promise to improve the long-term success of ablating ATs from the LA.

Background Ablation of atrial tachycardia (AT) that occurs after cardiac surgery or prior ablation often requires complex lesion sets. In combination with the pre-existing atrial scar, these lesion sets may result in inadvertent intra-atrial conduction block. This study reports the phenomenon of incidental isolation of right atrial (RA) regions that occurs secondary to AT ablation, which in some cases results in profound bradycardia due to sinus exit block. Methods and results Intracardiac electrograms were examined in consecutive patients who underwent AT ablation in the RA. Cases of localized isolation of the RA were defined as areas that developed electrical dissociation during ablation. Of 132 patients having ablation in both the RA free wall and the cavotricuspid isthmus (CTI), 10 (7.6%) developed unintentional isolation of the lateral RA. Five of these patients had prior mitral valve surgery, comprising 12.2% of all 41 patients with mitral surgery who underwent ablation in the CTI and the RA free wall. All patients with regional isolation had a pre-existing scar in the lateral wall of the RA. In six patients, isolation of the lateral RA resulted in profound bradycardia due to exit block from the peri-sinus node myocardium. Conclusions Complex ablation lesions in patients with prior valve surgery, prior ablation, or atrial myopathy may result in unintended localized conduction block in the RA. In some cases, isolation of the lateral RA can result in complete sinus exit block with profound bradycardia requiring pacemaker implantation.

Atrial tachycardias (ATs) may be classified into three broad categories: focal ATs, macroreentry and localised reentry – also known as ‘microreentry’. Features that distinguish these AT mechanisms include electrogram characteristics, responses to entrainment and pharmacological sensitivities. Focal ATs may occur in structurally normal hearts but can also occur in patients with structural heart disease. These typically arise from preferential sites such as the valve annuli, crista terminalis and pulmonary veins. Macro-reentrant ATs occur in the setting of atrial fibrosis, often after prior catheter ablation or post atriotomy, but also de novo in patients with atrial myopathy. High-resolution mapping techniques have defined details of macro-reentrant circuits, including zones of conduction block, scar and slow conduction. Localised reentry occurs in the setting of diseased atrial myocardium that supports very slow conduction. A characteristic feature of localised reentry is highly fractionated, low-amplitude electrograms that encompass most of the tachycardia cycle length over a small diameter. Advances in understanding the mechanisms of ATs and their signature electrogram characteristics have improved the efficacy and efficiency of catheter ablation.

Aims Although catheter ablation has emerged as an important therapy for patients with symptomatic atrial fibrillation (AF), there are limited data on sex-based differences in outcomes. We sought to compare in-hospital outcomes and 30-day readmissions of women and men undergoing AF ablation. Methods and results Using the United States Nationwide Readmissions Database, we analysed patients undergoing AF ablation between 2010 and 2014. Based on ICD-9-CM codes, we identified co-morbidities and outcomes. Multivariable logistic regression and inverse probability-weighting analysis were performed to assess female sex as a predictor of endpoints. Of 54 597 study patients, 20 623 (37.7%) were female. After adjustment for age, co-morbidities, and hospital factors, women had higher rates of any complication [adjusted odds ratio (aOR) 1.39; P Conclusions Independent of age, co-morbidities, and hospital factors, women have higher rates of complications and readmissions following AF ablation. Sex-based differences and disparities in the management of AF need to be explored to address these gaps in outcomes.

Outcomes data regarding atrial fibrillation treatment in chronic kidney disease are lacking. Available data and unanswered questions in this realm will be discussed, along with how the present manuscript fits into the overall literature of this field.

Introduction The impact of atrial arrhythmias on coronavirus disease 2019 (COVID‐19)‐associated outcomes are unclear. We sought to identify prevalence, risk factors and outcomes associated with atrial arrhythmias among patients hospitalized with COVID‐19. Methods An observational cohort study of 1053 patients with severe acute respiratory syndrome coronavirus 2 infection admitted to a quaternary care hospital and a community hospital was conducted. Data from electrocardiographic and telemetry were collected to identify atrial fibrillation (AF) or atrial flutter/tachycardia (AFL). The association between atrial arrhythmias and 30‐day mortality was assessed with multivariable analysis. Results Mean age of patients was 62 ± 17 years and 62% were men. Atrial arrhythmias were identified in 166 (15.8%) patients, with AF in 154 (14.6%) patients and AFL in 40 (3.8%) patients. Newly detected atrial arrhythmias occurred in 101 (9.6%) patients. Age, male sex, prior AF, renal disease, and hypoxia on presentation were independently associated with AF/AFL occurrence. Compared with patients without AF/AFL, patients with AF/AFL had significantly higher levels of troponin, B‐type natriuretic peptide, C‐reactive protein, ferritin and d‐dimer. Mortality was significantly higher among patients with AF/AFL (39.2%) compared to patients without (13.4%; p

Idiopathic sustained focal right ventricular tachycardia (VT) is most frequently due to outflow tract (OT) tachycardia. This arrhythmia is recognized by its characteristic ECG pattern and sensitivity to adenosine. However, there are other forms of idiopathic, focal sustained VT that originate from the right ventricle (RV), which are less well appreciated and easily overlooked. This review will identify the characteristic features and electrophysiologic properties of these forms of RV VT, including those originating from the tricuspid annulus, right ventricular papillary muscles, and moderator band as well as variants of classic RVOT tachycardia and those due to microreentry in the presence of preclinical disease. Recognition of these subtypes of focal RV tachycardia should facilitate targeted therapy.

Aims Due to the complex anatomy of the left ventricular (LV) and right ventricular (RV) papillary muscles (PMs), PM ventricular arrhythmias (VAs) can be challenging to target with ablation. We sought to compare the outcomes of robotic magnetic navigation-guided (RMN) ablation and manual ablation of VAs arising from the LV and RV PMs. Methods and results We evaluated 35 consecutive patients (mean age 65 ± 12 years, 69% male) who underwent catheter ablation of 38 VAs originating from the LV and RV PMs as confirmed by intracardiac echocardiography. Catheter ablation was initially performed using RMN-guidance in 24 (69%) patients and manual guidance in 11 (31%) patients. Demographic and procedural data were recorded and compared between the two groups. The VA sites of origin were mapped to 20 (53%) anterolateral LV PMs, 14 (37%) posteromedial LV PMs, and 4 (11%) RV PMs Acute successful ablation was achieved for 20 (74%) VAs using RMN-guided ablation and 8 (73%) VAs using manual ablation (P = 1.000). Fluoroscopy times were significantly lower among patients undergoing RMN ablation compared to patients undergoing manual ablation [median 7.3, interquartile range (IQR) 3.9-18 vs. 24 (16-44) min; P = 0.005]. Retrograde transaortic approach was used in 1 (4%) RMN patients and 5 (46%) manual patients (P = 0.005). No procedural complications were seen in study patients. Conclusion Use of an RMN-guided approach to target PM VAs results in comparable success rates seen with manual ablation but with lower fluoroscopy times and decreased use of transaortic retrograde access.

Background Left atrial thrombus (LAT) and dense spontaneous echocardiographic contrast (SEC) detected by transesophageal echocardiography (TEE) in patients on continuous direct oral anticoagulants (DOAC) therapy before catheter ablation of atrial fibrillation (AF) or atrial flutter (AFL) have been described. Objective We sought to compare rates of TEE-detected LAT and dense SEC among patients taking different DOACs. Methods We evaluated 609 consecutive patients from 3 tertiary hospitals (median age 65 years; interquartile range 58–71 years; 436 (72%) men) who were on ≥4 weeks of continuous DOAC therapy (dabigatran, n=166 [27%]; rivaroxaban, n=257 [42%]; or apixaban, n=186 [31%]) undergoing TEE before catheter ablation of AF/AFL. Demographic, clinical, and TEE data were collected for each patient. Results Despite ≥4 weeks of continuous DOAC therapy, 17 patients (2.8%) had LAT and 15 patients (2.5%) had dense SEC detected by TEE. The rates of LAT were 3.0%, 3.5%, and 1.6% for patients on dabigatran, rivaroxaban, and apixaban, respectively ( P = .482). The rates of dense SEC were 1.2%, 3.5%, and 2.2% for patients on dabigatran, rivaroxaban, and apixaban, respectively ( P = .299). Congestive heart failure (odds ratio 4.4; 95% confidence interval 1.6–12; P = .003) and moderate/severe left atrial enlargement (odds ratio 3.1; 95% confidence interval 1.1–8.6; P = .026) were independent predictors of LAT. Conclusion In this study, ∼3% of patients on continuous DOAC therapy had LAT detected before catheter ablation of AF/AFL. Specific DOAC therapy did not significantly affect the rates of LAT detection.

Introduction Recovery of conduction has been demonstrated in >50% of patients who receive pacemakers (PPMs) for high-degree atrioventricular block (HD-AVB) after transcatheter aortic valve replacement (TAVR). Little information is available about the time course of conduction recovery in these patients and if any features predict early recovery of conduction. Methods A retrospective review was performed of patients who underwent TAVR with balloon and self-expanding valves who required PPMs for HD-AVB. Serial PPM interrogations were analyzed to detect recovery of AV conduction. Analysis was performed to identify predictors and timing of conduction recovery. Results Of a total population of 578 patients, 54 (9%) received PPMs for HD-AVB. In multivariate analysis, predictors of HD-AVB requiring a PPM included age (p = 0.014), right bundle branch block (OR 7.33 [3.64-14.8], p

While outcomes after de novo cardiac resynchronization therapy (CRT) implantations have been reported, there are limited data on CRT upgrade procedures.The purpose of this study was to examine trends and in-hospital outcomes of patients undergoing CRT upgrade procedures by using a large national inpatient database.Using the National Inpatient Sample database, we identified all patients undergoing CRT upgrade and de novo CRT implants between 2003 and 2013. Rates of in-hospital adverse events such as death, cardiac perforation, pneumothorax, and lead revision were examined. Multivariate regression analysis was performed to compare outcomes after CRT upgrade and those after de novo CRT implant procedures.Between 2003 and 2013, 19,546 CRT upgrade procedures and 464,246 de novo CRT implants were recorded. Rates of in-hospital mortality of patients undergoing CRT upgrade were significantly higher than those of patients undergoing de novo CRT implant (1.9% vs 0.8%; P.001). Compared with de novo CRT implants, CRT upgrades were independently associated with increased mortality (adjusted odds ratio [OR] 1.91; 95% confidence interval [CI] 1.67-2.19; P.001), cardiac perforation (OR 3.20; 95% CI 2.71-3.77; P.001), and need for lead revision (OR 2.09; 95% CI 1.88-2.3; P.001).In a large national inpatient cohort, CRT upgrade procedures were associated with higher rates of in-hospital mortality and procedural complications as compared with de novo CRT implants.

S-ICD Candidacy Among Ventricularly Paced PatientsIntroduction The subcutaneous implantable cardioverter defibrillator (ICD) has emerged as a viable therapeutic option for patients who are deemed high risk for sudden cardiac death. Previous studies have shown that 7–15% of patients are not candidates for the S-ICD based on their intrinsic QRS/T-wave morphology. Presently, it is not known if the S-ICD can be considered as supplementary therapy in patients who are ventricularly paced. We sought to determine the proportion of ventricularly paced patients who would qualify for an S-ICD. Methods and Results We evaluated 100 patients with transvenous pacemakers/ICDs, including 25 biventricular devices to determine S-ICD candidacy during right ventricular (RV) pacing and biventricular pacing based on the recommended QRS:T-wave ratio screening template. Fifty-eight percent of patients qualified for an S-ICD based on their QRS morphology during ventricular pacing. More patients during biventricular pacing met criteria compared to during RV pacing alone (80% vs. 46%, P

Introduction The role of focal impulse and rotor modulation (FIRM)-guided ablation for the treatment of atrial fibrillation (AF) remains unclear. Previous studies on the FIRM-guided ablation outcomes have been limited by a focus on AF termination as an endpoint and by patient population heterogeneity. We sought to determine differences in rates of AF termination, inducibility, and recurrence in patients with persistent AF undergoing first-time ablation with a FIRM-guided approach compared with patients undergoing conventional ablation. Methods and results Eight-five consecutive patients (38 FIRM, 47 conventional) with persistent AF undergoing first-time ablation were retrospectively analyzed. There were no significant differences in the rates of AF termination in the FIRM group compared to the conventional group (26% vs 15%; P = .15). Rates of inducible AF after ablation were 37% in the FIRM group and 30% in the conventional group (P = .32). Over a median follow-up of 2.4 years, the rates of freedom from AF were similar between the FIRM and conventional groups (1-year freedom from AF 65% vs 50%, respectively; P = .18). Procedural termination of AF with either FIRM ablation or conventional ablation was not associated with any significant reduction in AF recurrence. Conclusion A FIRM-guided approach was not associated with a significant difference in freedom from AF when compared to conventional ablation. Termination of AF with ablation was not associated with increased freedom from AF. While AF termination using substrate-based ablation may have mechanistic implications for understanding AF rotor physiology, its impact on clinical outcomes remains unclear.

In some elderly patients with atrial fibrillation, especially in combination with heart failure, a rate control strategy may be preferred. When pharmacological therapy is ineffective or not tolerated, it is reasonable to perform atrioventricular (AV) node ablation with ventricular pacing. We describe a case in which this approach was necessary for management. However, the presence of periprocedural, drug-induced AV block just before ablation provided a unique and challenging circumstance. We discuss the steps taken to ensure a successful procedure.

Background: Patients undergoing catheter ablation of myocardial infarction–associated ventricular tachycardia (VT) have significant comorbidities that can increase the risks of adverse outcomes. The rates of readmissions after VT ablation are unknown. We sought to examine in-hospital outcomes, costs, and 30-day readmissions after catheter ablation of myocardial infarction–associated VT. Methods: Using the Nationwide Readmissions Database, we evaluated 4109 admissions for catheter ablation of myocardial infarction–associated VT occurring between 2010 and 2015. On the basis of International Classification of Diseases, Ninth Revision, Clinical Modification and Clinical Classification Software codes, we identified comorbidities, procedural complications, 30-day readmissions, and costs associated with VT ablation. Results: The index admission in-hospital mortality rate and procedural complication rate after VT ablation were 2.7% and 11.5%, respectively. Independent predictors of mortality included pulmonary hypertension, lung disease, obesity, and coagulopathy. Following discharge after VT ablation, the 30-day readmission rate was 19.2% with a median time to readmission of 10.0 days (IQR, 3.8–17.6 days) and an in-hospital mortality rate of 2.9%. Cardiac causes accounted for 74% of readmissions, with VT and congestive heart failure constituting 41% and 14% of all readmissions, respectively. Pulmonary hypertension, congestive heart failure, smoking, chronic pulmonary disease, and prolonged index hospitalization were significant independent predictors of 30-day readmission. After adjustment, 30-day readmissions were associated with a 38.9% increase in cumulative hospitalization costs. Conclusions: Thirty-day readmissions after catheter ablation of VT occur in nearly 1 out of 5 cases, with the majority of readmissions being caused by recurrent VT or congestive heart failure. Baseline comorbidities are significant predictors of procedural mortality, complications, and readmissions. Strategies to reduce recurrent VT postablation by improving procedural success, optimizing postablation heart failure treatment, and ensuring close postdischarge follow-up may help reduce readmissions and healthcare costs.

Left atrial thrombus (LAT) may be detected by transesophageal echocardiography (TEE) in patients with atrial fibrillation (AF) or flutter (AFL) despite continuous anticoagulation therapy. We sought to examine the rates and timing of LAT resolution in response to changes in anticoagulation regimen. A retrospective study of 1517 consecutive patients on ≥ 4 weeks continuous oral anticoagulation (OAC) undergoing TEE prior to either direct current cardioversion or catheter ablation for AF or AFL was performed. Patients who had LAT on index TEE imaging and had follow-up TEEs were analyzed. Despite ≥ 4 weeks of continuous anticoagulation therapy, 63 (4.2%) patients had LAT. Forty-four patients (median age 67 [IQR 58, 74]; 33 [75%] male; 25 [57%] on direct oral anticoagulant [DOAC]) had follow-up TEEs performed. Upon detection of LAT on index TEE, 8 patients switched from warfarin to a DOAC, 21 patients switched from a DOAC to warfarin or another DOAC, and 15 patients remained on the same OAC. Over median 4.2 months (IQR 2.9, 6.6), LAT resolution was seen in 25 (57%) patients. Of the 25 patients who had LAT resolution, 7 (28%) required TEE imaging > 6 months after index TEE to show clearance of thrombus. Rates of LAT resolution were similar between patients who had alterations in OAC and those who did not (52 vs. 60%; P = 0.601). After initial detection of left atrial thrombus despite uninterrupted anticoagulation for atrial fibrillation or flutter, > 40% patients have persistent clot despite additional extended anticoagulation.