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Pericardial bleeding is a rare but life-threatening complication of atrial fibrillation (AF) ablation. Patients taking uninterrupted oral anticoagulation (AC) may be at increased risk for refractory bleeding despite pericardiocentesis and administration of protamine. In such cases, andexanet alfa can be given to reverse rivaroxaban or apixaban. In this study, we aim to describe the rate of acute hemostasis and thromboembolic complications with andexanet for refractory pericardial bleeding during AF ablation.In this multicenter, case series, participating centers identified patients who received a dose of apixaban or rivaroxaban within 24 hours of AF ablation, developed refractory pericardial bleeding during the procedure despite pericardiocentesis and administration of protamine and received andexanet. Eleven patients met inclusion criteria, with mean age of 73.5 ± 5.3 years and median CHAIn patients on uninterrupted apixaban or rivaroxaban, who develop refractory pericardial bleeding during AF ablation, andexanet can achieve hemostasis thereby avoiding the need for emergent surgery. However, there is a risk of thromboembolism following administration. This article is protected by copyright. All rights reserved.

The subcutaneous (S-) implantable cardioverter-defibrillator (ICD) is an alternative to the transvenous (TV-) ICD that is increasingly implanted in younger patients; data on the safety and effectiveness of the S-ICD in older patients are lacking.The purpose of this study was to compare outcomes among older patients who received an S- or TV-ICD.The authors compared S-ICD and single-chamber TV-ICD implants in Fee-For-Service Medicare beneficiaries using the National Cardiovascular Data Registry ICD Registry. Outcomes were ascertained from Medicare claims data. Cox regression or competing-risk models (with TV-ICD as reference) with overlap weights were used to compare death and nonfatal outcomes (device reoperation, device removal for infection, device reoperation without infection, and cardiovascular admission), respectively. Recurrent all-cause readmissions were compared using Anderson-Gill models.A total of 16,063 patients were studied (age 72.6 ± 5.9 years, 28.4% women, ejection fraction 28.3 ± 8.9%). Compared with TV-ICD patients (n = 15,072), S-ICD patients (n = 991, 6.2% overall) were more often Black, younger, and dialysis dependent and less likely to have history of atrial fibrillation or flutter. In adjusted analyses, there were no differences between device type and risk of all-cause mortality (HR: 1.020; 95% CI: 0.819-1.270), device reoperation (subdistribution [s] HR: 0.976; 95% CI: 0.645-1.479), device removal for infection (sHR: 0.614; 95% CI: 0.138-2.736), device reoperation without infection (sHR: 0.975; 95% CI: 0.632-1.506), cardiovascular readmission (sHR: 1.087; 95% CI: 0.912-1.295), or recurrent all-cause readmission (HR: 1.072; 95% CI: 0.990-1.161).In a large representative national cohort of older patients undergoing ICD implantation, risk of death, device reoperation, device removal for infection, device reoperation without infection, and cardiovascular and all-cause readmission were similar among S- and TV-ICD recipients.

While obesity has been shown to be associated with elevated risk for Sudden Cardiac Death (SCD), studies examining its effect on outcomes in SCD victims have shown conflicting results. We aimed to describe the body mass index (BMI) distribution in a nationwide cohort of patients admitted for an out of hospital SCD (OHSCD), and the relationship between BMI and in‐hospital mortality. We drew data from the U.S. National Inpatient Sample (NIS), to identify cases of OHSCD. Patients were divided into six groups based on their BMI (underweight, normal weight, overweight, obese I, obese II, extremely obese). Socio‐demographic and clinical data were collected, mortality and length of stay were analyzed. Multivariate analysis was performed to identify predictors of mortality. Among a weighted total of 2330 hospitalizations for OHSCD in patients with documented BMI, the mean age was 62.3 ± 29 years, 52.4% were male and 62% were white. The overall rate of in‐hospital mortality was 69.3%. A U‐shaped relationship between the BMI and mortality was documented, as patients with 25

BACKGROUND Catheter ablation (CA) for ventricular arrhythmias (VAs) is increasingly utilized in recent years. We aimed to investigate the nationwide trends in utilization and procedural complications of CA for VAs in patients with mechanical valve (MV) prosthesis. METHODS We drew data from the US National Inpatient Sample database to identify cases of VA ablations, including premature ventricular contraction and ventricular tachycardia, in patients with MVs, between 2003 and 2015. Sociodemographic and clinical data were collected and the incidence of catheter ablation complications, mortality, and length of stay were analyzed. We compared the outcomes to a propensity-matched cohort of patients without prior valve surgery. RESULTS The study population included a weighted total of 647 CA cases in patients with prior MVs. The annual number of ablations almost doubled, from 34 ablations on average during the "early years" (2003-2008) to 64 on average during the "late years" (2009-2015) of the study (p = .001). Length of stay at the hospital did not differ significantly between patients with MVs and 649 matched patients without prior MVs (5.4 ± 0.4, 4.7 ± 0.3 days, respectively, p = .12). The data revealed a trend toward a higher incidence of complications (12.6% vs. 7.5% respectively, p = .14) and mortality (3.7% vs. 0.7%, respectively, p = .087) among patients with MVs compared to the matched control group, not reaching statistical significance. CONCLUSION The data show increased utilization of VA ablations in patients with MVs and a trend toward a higher incidence of in-hospital mortality and complications compared to the propensity-matched control group without MVs.

We report a case of catheter ablation of Brugada syndrome in a patient with refractory ventricular fibrillation despite quinidine therapy. We performed epicardial substrate mapping, which identified an area of abnormal fractionated, prolonged electrogram in the anterior right ventricular outflow tract. Warm saline infusion into the pericardial space induced further delay of the local electrogram, consistent with Brugada syndrome physiology. Coronary angiography confirmed that the area was distant from major coronary arteries. Ablation was performed in this area, which eliminated local abnormal electrograms and led to the disappearance of coved-type ST elevation in V1–V2. No ventricular fibrillation had recurred by five months of follow-up.

Atrial fibrillation (AF) and heart failure (HF) are the 2 emerging epidemics in global cardiovascular disease. AF remains the most common cardiac arrhythmia, affecting over 33 million adults worldwide, and continues to increase in prevalence as the populations of many nations age. The prevalence of HF also surges, now afflicting 37 million adults globally. Interestingly, these 2 disease processes share many of the same risk factors and stem from many of the same pathophysiologic derangements, with AF occurring in over half of all patients with HF and HF occurring in over one third of all patients with AF. Furthermore, exacerbation of one of these ailments often drives decompensation or compromises therapy of the other, and it has been widely reported that coexistence of AF in patients with HF portends a poorer prognosis. As a result, many clinicians now routinely face the problem of AF in the patient with HF. In this review, we highlight the fundamental pathologic forces embedded in the relationship between AF and HF and then proceed to a discussion on the management of these complex patients with a detailed exploration of the clinical data.

This clinical review focuses on both current devices approved by the United States Food and Drug Administration and investigational devices available for left atrial appendage (LAA) closure. Specifically, the article describes the anatomical considerations that are particularly relevant from a procedural standpoint. In addition, we have also focused on the technical aspects of the procedure.

Highlights •Ambulatory cardiac monitoring devices allow collection of long-term data for diagnostics of clinical relevance. •Recent advancements have enabled affordable and reliable devices for early detection of important physiological events. •Improving adoption in the general population is leading to new paradigms of health care and personalized medicine.

Background Data regarding the use of high-power short-duration (HPSD) radiofrequency (RF) in combination with half-normal saline irrigation for catheter irrigation is limited. Objectives This study investigated the safety and efficacy of using HPSD RF ablation in combination with half-normal saline irrigation for the treatment of AF. Methods One hundred consecutive patients with AF underwent RF ablation using HPSD combined with half-normal saline for catheter irrigation. In addition, the following ablation strategies were used: 1 mm tags for the display of ablation lesions on the mapping system, high-frequency jet ventilation (HFJV), low contact force, pacing after ablation to verify areas of noncapture, atrial/ventricular pacing at 500 to 700 ms to aid in catheter stability, use of two skin electrodes to reduce impedance, and post-ablation adenosine infusion. Power was started at 40-45 W and was modulated manually based on impedance changes. Results The average age of patients was 65.2 years and 70% were male. Forty-seven percent had paroxysmal AF and the average CHA2 DS2 -VASc score was 2.1±1.6. The average power and lesion duration were 38.1 ± 3.3 W and 8.1 ± 2.3 seconds, respectively. During a median follow-up period of 321 ± 139 days, 89% of the patients remained free from any atrial arrhythmias after a single RF ablation procedure. No procedure-related death, stroke, pericardial effusion, or atrioesophageal fistula occurred during follow-up. Conclusions Catheter ablation using HPSD RF lesions in combination with half-normal saline irrigation and is safe and effective, and results in high rate of freedom from AF. This article is protected by copyright. All rights reserved.

Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death. We developed a 12-lead, blue-tooth/Smart-Phone (Android) based electrocardiogram (ECG) acquisition and monitoring system (cvrPhone), and an application to estimate RA, in real-time. In in-vivo swine studies (N = 17), 12-lead ECG signals were recorded at baseline and following coronary artery occlusion. RA was estimated using the Fast Fourier Transform (FFT) method using a custom developed algorithm in JAVA. Underlying ischemia was detected using a custom developed ischemic index. RA from each lead showed a significant (p

Background Left atrial appendage closure (LAAC) is an alternative to long-term anticoagulation for thromboembolic protection in patients with atrial fibrillation (AF) and high bleeding risk. Short-term Warfarin use following LAAC is well-studied, while data pertaining to novel oral anticoagulant (NOAC) use in this setting is less robust. Specifically, data regarding the safety and efficacy of postprocedural NOAC use in high-risk patients is lacking. Objective To compare the safety and efficacy of Warfarin and NOAC use in a high-risk patient population undergoing LAAC with the WATCHMAN device. Methods From November 2015 to October 2017, 97 patients underwent LAAC with the WATCHMAN device. All patients were discussed at a multidisciplinary meeting prior to device implantation. Longitudinal data were collected and analyzed for a composite endpoint of stroke and death at 8 months, and major bleeding at 3 and 6 months. Results Among the 90 patients included in the safety and efficacy analysis, 43 were prescribed Warfarin and 47 were prescribed NOACs. Baseline characteristics were comparable between study groups. There were no procedural complications and no significant differences in the incidence of death and stroke at 8 months or major bleeding at 3 and 6 months. Conclusion For patients with AF at high risk of both thromboembolic and hemorrhagic events, NOACs as compared to Warfarin, seem to be safe and effective for short-term anticoagulation following LAAC with the WATCHMAN device. Further validation in large randomized controlled trials is required.

Objectives The aim of this study was to assess the variations in ventricular arrhythmia (VA) occurrence according to seasons, months of the year, days of the week, and the time of day in a large implantable cardioverter-defibrillator patient population. Background Limited data exist on how VA occurrence varies as a function of time. Methods Data from 6 prospective studies were pooled to assess VA frequency over time. All adjudicated episodes of VAs ≤500 ms were included. VA distribution as a function of hour, day, month, and season were assessed through the construction of 4 negative binomial models. The models included a random patient effect and offset for days spent in each time period. Results Among 3,969 patients, 7,126.8 cumulative device-years with an average follow-up duration of 1.8 ± 1.4 years/patient were analyzed. VA occurrence was higher in the spring than the summer (0.86% vs. 0.70%; p = 0.009) but not significantly different from the fall (0.74%; p = 0.069) or winter (0.84%; p = 0.732). The estimated probability of occurrence of at least 1 VA episode in each 1-h block during the hours of 8 am to 10 pm over 365 days (0.10% to 0.12%) was higher (estimated 35% to 63% higher) than the referent period of midnight to 1 am (0.07%). No significant variations in VA occurrence were observed according to weekday and individual months of the year. Conclusions Significantly higher VA occurrence in the spring and during the hours of 8 am to 10 pm were observed. Additional studies are needed to further understand the reasons for these observations, which may involve variations in temperature or differences in catecholamine triggers.

Ambulatory monitoring devices are enabling a new paradigm of healthcare by continuously collecting, processing, and interpreting long-term data aiming to provide reliable clinical diagnoses. These devices are becoming increasingly popular, both among healthcare practitioners and patients, for long-term continuous monitoring of cardiac diseases. Advancements in the fields of hardware technologies and software algorithms have enabled solutions that are both affordable and reliable, allowing monitoring of vulnerable populations from the comfort of their homes. These devices provide early detection of important physiological events, providing patients with timely alerts to seek medical attention. In this chapter, we aim to summarize recent developments and challenges in the area of ambulatory and remote monitoring solutions for cardiac and respiratory diagnostics. We present solutions based on wearable devices, smartphones/tablets, as well as implantable sensors. Finally, we present an overview of the limitations of current technologies, their effectiveness, and adoption by the general population, and we discuss some of the recently proposed methods that may help overcome those challenges.

With the ever-increasing amount of biomedical data gathered by hospital monitors, wearable devices, and the Internet of Things (IoT) and also with the advancement in artificial intelligence (AI) and computational hardware, there is an explosion of interest in applying AI in solving problems in biomedicine and healthcare. This chapter provides a basic introduction to AI and explains the motivation for using AI in medicine. The main body of this chapter summarizes the recent applications of AI to improve patients’ cardiovascular and respiratory system outcomes. At the end, the limitations and the forecasted future of AI in medicine are also discussed.

The future of the American Board of Internal Medicine Maintenance of Certification (MOC) program is at a crossroads. The current MOC program lacks a clear visible mission, adds to modern health care’s onerous bureaucracy, and thus pulls physicians from the most important humanistic aspects of their profession. The aim of the MOC program should be to promote the best patient care by ensuring certified physicians maintain core skills through continuous education and evaluation. The program should focus on education and be designed with the rigorous obligations of practicing physicians in mind. Moving forward, the American Board of Internal Medicine should cocreate MOC with the physician community and apply innovative adult education techniques. Over time, data-driven methods and member feedback should be used to provide continuous program improvement. This review describes the origins of the current state of MOC, explores its evidence base, provides examples of model programs for the maintenance of complex professional skills, and outlines guiding principles for the future of MOC.

Introduction: The subcutaneous (S-) implantable cardioverter defibrillator (ICD) is an alternative to the transvenous (TV-) ICD that is increasingly implanted in younger patients. However, data on the safety and effectiveness of the S-ICD in older patients are lacking. Methods: We compared S-ICD and single chamber TV-ICD implants in Medicare beneficiaries (≥65yrs) using National Cardiovascular Data Registry ICD Registry data from 9/28/2012 through 12/31/2017. We excluded patients with prior pacemaker or ICD, an indication for pacing or resynchronization, and those undergoing implant in an acute setting. Mortality status was determined using the Medicare master summary beneficiary file. Cox regression analyses with overlap weights were used to compare all-cause mortality. Mean cumulative counts of all-cause readmissions were compared among for Fee for Service beneficiaries. Results: A total of 23,717 patients met inclusion criteria [mean age 72.7±5.8 years, 29% female, 69% ischemic heart disease, 33% atrial arrhythmias, 49% NYHA II, 31.7% NYHA III, ejection fraction (EF) 28±9%, 3% dialysis dependent, 20% with prior ventricular tachycardia]. Compared to TV-ICD patients (n=22,264), S-ICD patients (n=1,453, 6% overall) were more often male, black, diabetic, dialysis dependent and were less likely to have atrial or ventricular arrhythmias or ischemic heart disease. There was no difference in age or EF between the 2 groups. In adjusted analyses, during a median follow-up of 2.3 years (IQR: 1.2 - 3.5), there was no difference between the 2 groups in all-cause mortality (HR 1.04, CI 0.91-1.17, Figure A ) or readmissions (based on overlap of confidence intervals, Figure B ). Conclusions: In a large representative cohort of older patients undergoing ICD implant, all-cause mortality and readmission were similar among S-ICD and TV-ICD recipients. These findings support use of the S-ICD for the prevention of sudden cardiac death in appropriately selected older patients.

Ventricular tachyarrhythmias have heterogeneous etiologies, clinical consequences, and treatment strategies. Distinguishing ventricular tachyarrhythmias from supraventricular tachycardia (SVT) with aberrancy clinically and on the surface electrocardiogram can be challenging, yet has substantial therapeutic implications. A wide body of randomized clinical trial data has emerged addressing the efficacy of implantable cardioverter defibrillators (ICDs) for the prevention of sudden cardiac death.

Radiofrequency ablation (RFA) remains a highly effective therapy in the management of paroxysmal atrial fibrillation (PAF) and is an important therapeutic option in the management of persistent atrial fibrillation (PeAF) when clinically indicated. Lesion size is influenced by many parameters, which include those related to energy application (RFA power, temperature, and time), delivery mechanism (electrode size, orientation, and contact force), and the environment (blood flow and local tissue contact, stability, and local impedance). Successful durable RFA is dependent on achieving lesions that are reliably transmural and contiguous, whilst also avoiding injury to the surrounding structures. This review focuses on the variables that can be adjusted in connection with RFA to achieve long-lasting lesions that enable patients to derive the maximum sustained benefit from pulmonary vein isolation and additional lesion sets if utilized.

A 67-year-old female with prior medical history of HTN and asthma presented with acute-onset dyspnea and nausea for 4 days prior to admission. Upon initial encounter in the emergency room, she was found to have findings of abnormal pulmonary infiltrates and consequent workup revealed COVID-19. During further hospital course, the patient developed abnormal EKG and echocardiographic findings consistent with stress-induced cardiomyopathy.

Background Atrial fibrillation (AF) is common and bears a major clinical impact in patients with hypertrophic cardiomyopathy (HCM). We aimed to investigate the use and real‐world safety of catheter ablation for AF in patients with HCM. Methods and Results We drew data from the US National Inpatient Sample to identify cases of AF ablation in HCM patients between 2003 and 2015. Sociodemographic and clinical data were collected, and incidence of catheter ablation complications, mortality, and length of stay were analyzed, including trends between the early (2003–2008) and later (2009–2015) study years. Among a weighted total of 1563 catheter ablation cases in patients with HCM, the median age was 62 (interquartile range, 52–72), 832 (53.2%) were male, and 1150 (73.6%) were white. The average annual volume of AF ablations in patients with HCM doubled between the early and the later study period (79–156). At least 1 complication occurred in 16.1% of cases, and the in‐hospital mortality rate was 1%. Cardiac and pericardial complications declined from 8.8% to 2.3% and from 2.8% to 0.9%, respectively, between the early and the later study years ( P Conclusions Despite some decline in procedural complications over the years, catheter ablation for AF is still associated with a relatively high periprocedural morbidity and even mortality in patients with HCM. This emphasizes the importance of careful clinical consideration, by an experienced electrophysiologist, in referring patients with HCM for an AF ablation.

Background: Repolarization alternans (RA) has been implicated in the pathogenesis of ventricular arrhythmias and sudden cardiac death. Methods: We have developed a real-time, closed-loop system to record and analyze RA from multiple intracardiac leads, and deliver dynamically R-wave triggered pacing stimuli during the absolute refractory period. We have evaluated the ability of this system to control RA and reduce arrhythmia susceptibility, in vivo. Results: R-wave triggered pacing can induce RA, the magnitude of which can be modulated by varying the amplitude, pulse width, and size of the pacing vector. Using a swine model (n=9), we demonstrate that to induce a 1 µV change in the alternans voltage on the body surface, coronary sinus and left ventricle leads, requires a delivered charge of 0.04±0.02, 0.05±0.025, and 0.06±0.033 µC, respectively, while to induce a one unit change of the K score , requires a delivered charge of 0.93±0.73, 0.32±0.29, and 0.33±0.37 µC, respectively. For all body surface and intracardiac leads, both Δ(alternans voltage) and ΔK score between baseline and R-wave triggered paced beats increases consistently with an increase in the pacing pulse amplitude, pulse width, and vector spacing. Additionally, we show that the proposed method can be used to suppress spontaneously occurring alternans (n=7), in the presence of myocardial ischemia. Suppression of RA by pacing during the absolute refractory period results in a significant reduction in arrhythmia susceptibility, evidenced by a lower S rank score during programmed ventricular stimulation compared with baseline before ischemia. Conclusions: We have developed and evaluated a novel closed-loop method to dynamically modulate RA in a swine model. Our data suggest that suppression of RA directly reduces arrhythmia susceptibility and reinforces the concept that RA plays a critical role in the pathophysiology of arrhythmogenesis.

BACKGROUND: Dual-source computed tomography (CT) can evaluate left ventricular (LV) dyssynchrony, myocardial scar and coronary venous anatomy in patients undergoing cardiac resynchronization therapy (CRT). OBJECTIVE: We aim to determine if dual-source CT predicts clinical CRT outcomes and reduces intra-procedural time. METHODS: In this prospective study, 54 patients scheduled for CRT (age 63±11, 74% male) underwent pre-procedural CT to assess their venous anatomy as well as CT-derived dyssynchrony metrics and myocardial scar. Based on the 1:1 randomization, the implanting physician had pre-implant knowledge of the venous anatomy in half the patients. In blinded analyses, we measured time-to-maximal wall thickness and inward motion to determine 1) CT global and segmental dyssynchrony and 2) concordance of lead location to regional LV mechanical contraction. Endpoints were 6-month CRT response by Heart Failure Clinical Composite Score and 2-year major adverse cardiac events (MACE). RESULTS: There were 72% CRT responders and 17% with MACE. Two wall motion dyssynchrony indices (global and opposing anteroseptal-inferolateral walls) predicted MACE (p

Catheter ablation and antiarrhythmic drugs (AADs) are the most common rhythm-control strategies for atrial fibrillation (AF). Data comparing the rate of stroke and cardiovascular events between the treatment strategies are limited. Therefore, this observational study uses claims data to compare rate of cardiovascular hospitalization and stroke for patients with AF treated with ablation or AADs. Patients in the MarketScan dataset with AF between January 2010 and December 2014 were categorized in the ablation group if an atrial catheter ablation was performed, or in the AAD group if a relevant AAD was prescribed for AF but no ablation was performed. One year of history was required, and the index event was selected as the most recent ablation or AAD prescription closest to January 1, 2013. A 2:1 propensity score match was performed for age, gender, co-morbidities, and total medical cost in the year before index event. Outcomes included thromboembolic event (ischemic stroke, transient ischemic attack, or systemic embolism) and all cardiovascular hospitalizations. Of the 164,639 patients in the AAD group, 29,456 were matched to the 14,728 ablation patients. There were no significant differences in age (64 ± 10 in both groups), gender (58% male), or CHA2DS2-VASc score (3.2 ± 1.3). Risk of hospitalization with primary diagnosis of thromboembolic event was 41% greater in the AADs group (p

Atrial fibrillation is commonly coexistent with heart failure, and the management of the heart failure patient would be incomplete without an appreciation for atrial fibrillation management. There are many complications associated with oral anticoagulation in the prevention of stroke related to atrial fibrillation. In recent years, the advent of several percutaneous left atrial appendage (LAA) occlusion/closure strategies has sought to provide an alternative treatment modality. Here, we systematically review the published literature to investigate the efficacy and safety of percutaneous LAA occlusion/closure devices. We searched PubMed, EMBASE, Cochrane database of systematic reviews, and the FDA Medical Devices database. Using prespecified criteria, we identified studies of the Amplatzer Cardiac Plug (St. Jude Medical), Amplatzer Amulet (St. Jude Medical), Lariat suture delivery device (SentreHeart), and Watchman device (Boston Scientific). We analyzed 2 randomized controlled trials (RCT) and 15 non-randomized registries that satisfied the study criteria. The two RCT both studied the Watchman device versus standard warfarin therapy; the studies indicate that the Watchman may be non-inferior to warfarin. Long-term efficacy outcomes for the Watchman device are promising. Data regarding the Amplatzer Cardiac Plug, Amplatzer Amulet, and Lariat suture delivery device are limited by the paucity of RCT data. High-quality prospective research is needed to directly compare LAA occlusion/closure strategies against one another as well as versus the direct oral anticoagulation medications. Data regarding the role of LAA occlusion in the heart failure population are lacking.

Objectives This study sought to investigate the utilization of and in-hospital complications in patients undergoing catheter ablation in the United States from 2000 to 2013 by using the National Inpatient Sample and Nationwide Inpatient Sample. Background Catheter ablation has become a mainstay in the treatment of a wide range of cardiac arrhythmias. Methods This study identified patients 18 years of age and older who underwent inpatient catheter ablation from 2000 to 2013 and had 1 primary diagnosis of any of the following arrhythmias: atrial fibrillation, atrial flutter, supraventricular tachycardia, or ventricular tachycardia. Results An estimated total of 519,951 (95% confidence interval: 475,702 to 564,200) inpatient ablations were performed in the United States between 2000 and 2013. The median age was 62 years (interquartile range: 51 to 72 years), and 59.3% of the patients were male. The following parameters showed increasing trends during the study period: annual volume of ablations, number of hospitals performing ablations, mean age and comorbidity index of patients, rate of ≥1 complication, and length of stay (p Conclusions From 2000 to 2013, there was a substantial increase in the annual number of in-hospital catheter ablation procedures, as well as the rate of periprocedural complications nationwide. Low-volume centers had a significantly higher rate of complications.

We investigated the rates and reasons for crossover to alternative treatment strategies and its impact on mortality in patients who were enrolled in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial. Over a mean follow-up period of 3.5 years, 842 patients underwent crossover to the alternative treatment arms in AFFIRM. The rate of crossover from rhythm to rate control (594/2,033, 29.2%) was more frequent than the rate of crossover from rate to rhythm control (248/2,027, 12.2%, P < 0.0001). The leading reasons for crossover from rhythm to rate control were failure to achieve or maintain sinus rhythm (272/594, 45.8%) and intolerable adverse effects (122/594, 20.5%). In comparison, the major reasons for crossover from rate to rhythm control were failure to control atrial fibrillation symptoms (159/248, 64.1%) and intolerable adverse effects (9/248, 3.6%). This difference in crossover pattern was statistically significant (P < 0.0001). There was a significantly decreased risk of all-cause mortality (adjusted HR: 0.61, 95% CI: 0.48-0.78, P < 0.0001) and cardiac mortality (adjusted hazard ratio [HR]: 0.61, 95% confidence interval [CI]: 0.43-0.88, P = 0.008) in the subgroup of patients who crossed over from rhythm to rate control as compared to those who continued in rhythm control. There was a nonsignificant trend toward decreased all-cause (adjusted HR: 0.76, 95% CI: 0.53-1.10, P = 0.14) and cardiac mortality (adjusted HR: 0.70, 95% CI: 0.42-1.18, P = 0.18) in patients who crossed over from rate to rhythm control as compared to those who continued rate control.

Atrial fibrillation (AF) is an age-related arrhythmia of enormous socioeconomic significance. In recent years, our understanding of the basic mechanisms that initiate and perpetuate AF has evolved rapidly, catheter ablation of AF has progressed from concept to reality, and recent studies suggest lifestyle modification may help prevent AF recurrence. Emerging developments in genetics, imaging, and informatics also present new opportunities for personalized care. However, considerable challenges remain. These include a paucity of studies examining AF prevention, modest efficacy of existing antiarrhythmic therapies, diverse ablation technologies and practice, and limited evidence to guide management of high-risk patients with multiple comorbidities. Studies examining the long-term effects of AF catheter ablation on morbidity and mortality outcomes are not yet completed. In many ways, further progress in the field is heavily contingent on the feasibility, capacity, and efficiency of clinical trials to incorporate the rapidly evolving knowledge base and to provide substantive evidence for novel AF therapeutic strategies. This review outlines the current state of AF prevention and treatment trials, including the foreseeable challenges, as discussed by a unique forum of clinical trialists, scientists, and regulatory representatives in a session endorsed by the Heart Rhythm Society at the 12th Global CardioVascular Clinical Trialists Forum in Washington, DC, December 3-5, 2015.