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Objectives This study sought to evaluate the safety and effectiveness of catheter ablation of persistent atrial fibrillation (PsAF) using a porous tip contact force–sensing catheter. Backg...

Purpose The prospective, multicenter SMART SF trial demonstrated the acute safety and effectiveness of the 56-hole porous tip irrigated contact force (CF) catheter for drug-refractory paroxysmal atrial fibrillation (PAF) ablation with a low primary adverse event rate (2.5%), leading to FDA approval of the catheter. Here, we are reporting the long-term effectiveness and safety results that have not yet been reported. Methods Ablations were performed using the 56-hole porous tip irrigated CF catheter guided by the 3D mapping system stability module. The primary effectiveness endpoint was freedom from atrial tachyarrhythmia (including atrial fibrillation, atrial tachycardia, and/or atrial flutter), based on electrocardiographic data at 12 months. Atrial tachyarrhythmia recurrence occurring 3 months post procedure, acute procedural failures such as lack of entrance block confirmation of all PVs, and undergoing repeat procedure for atrial fibrillation in the evaluation period (91 to 365 days post the initial ablation procedure) were considered to be effectiveness failures. Results Seventy-eight patients (age 64.8 ± 9.7 years; male 52.6%; Caucasian 96.2%) participated in the 12-month effectiveness evaluation. Mean follow-up time was 373.5 ± 45.4 days. The Kaplan-Meier estimate of freedom from 12-month atrial tachyarrhythmia was 74.9%. Two procedure-related pericardial effusion events were reported at 92 and 180 days post procedure. There were no pulmonary vein stenosis complications or deaths reported through the 12-month follow-up period. Conclusions The SMART SF 12-month follow-up evaluation corroborates the early safety and effectiveness success previously reported for PAF ablation with STSF.

Atrial fibrillation (AF) carries substantial morbidity and mortality. Evidence-based guidelines have been synthesized into emergency department (ED) AF care pathways, but the effectiveness and scalability of such approaches are not well established. We thus evaluated the impacts of an algorithmic care pathway for ED management of non-valvular AF (EDAFMP) on hospital use and care process measures.We deployed a voluntary-use EDAFMP in 4 EDs (1 tertiary hospital, 1 cardiac hospital, 2 community hospitals) of an integrated delivery organization using a multifaceted implementation approach. We compared outcomes between patients with AF treated using the EDAFMP and historical and contemporaneous "usual care" controls, using a propensity-score adjusted generalized estimating equation. Patients with an index ED encounter for a primary visit reason of non-valvular AF (and no excluding concurrent diagnoses) were eligible for inclusion.Preimplementation (January 1, 2016-December 31, 2016), 628 AF patients were eligible; postimplementation (September 1, 2017-June 30, 2019), 1296, including 271 (20.9%) treated with the EDAFMP, were eligible. EDAFMP patients were less likely to be admitted than both historical (adjusted odds ratio [aOR], 95% confidence interval [CI]: 0.45, 0.29-0.71) and contemporaneous controls (aOR, 95%CI: 0.63, 0.46-0.86). ED visits and hospital readmissions over 90 days subsequent to index ED encounters were similar between postimplementation EDAFMP and usual care groups. EDAFMP patients were more likely to be prescribed anticoagulation (38% v. 5%,EDAFMP use is associated with decreased hospital admission during an index ED encounter for non-valvular AF, and improved delivery of AF care processes.

Background: There is limited evidence on the long-term clinical benefits of catheter ablation in patients with persistent atrial fibrillation. Methods: PRECEPT was a prospective, multicenter, single-arm Food and Drug Administration–regulated investigational device exemption clinical study. Patients were followed up to 15 months after ablation. Outcomes included use of antiarrhythmic drugs, rate of cardioversions and cardiovascular hospitalization, Atrial Fibrillation Effect on Quality-of-Life score, and Canadian Cardiovascular Society Severity of Atrial Fibrillation score. Results: A total of 333 enrolled persistent atrial fibrillation patients underwent ablation. The cardioversion rate decreased by 83% at the 9- to 15-month follow-up. Antiarrhythmic drug utilization decreased by 69% at 12 to 15 months post-ablation. The Kaplan-Meier estimate of freedom from cardiovascular hospitalization was 84.2% (95% CI, 80.2%–88.2%) at 15 months. Consistent improvements in mean Atrial Fibrillation Effect on Quality-of-Life composite (+50.0) were seen at 6 months, sustained at 15 months, and exceeded the minimum clinically important difference. Improvements in Atrial Fibrillation Effect on Quality-of-Life scores were significantly better among participants without documented atrial arrhythmia recurrences. By Canadian Cardiovascular Society Severity of Atrial Fibrillation symptom classification, >80% of patients were asymptomatic (class 0) at 15 months post-ablation compared with only 0.7% at baseline. Conclusions: Contact force–guided radiofrequency ablation of persistent atrial fibrillation was associated with a significant decrease in antiarrhythmic drug use, cardioversion rate, and hospitalization. Clinically meaningful improvements in quality of life were observed in all patients. The majority of the patients (>80%) were asymptomatic at 15 months post-ablation. The positive clinical impact of improved quality of life and reduced health care utilization may help with shared decision-making in persistent atrial fibrillation treatment. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02817776.

This study sought to evaluate the safety and effectiveness of catheter ablation of persistent atrial fibrillation (PsAF) using a porous tip contact force-sensing catheter.Although the safety and effectiveness of catheter ablation of paroxysmal atrial fibrillation are established, there are limited data on outcomes in patients with PsAF. As such, no ablation catheter is currently approved by the Food and Drug Administration for PsAF ablation.The prospective, multicenter, nonrandomized PRECEPT (Prospective Review of the Safety and Effectiveness of the THERMOCOOL SMARTTOUCH SF Catheter Evaluated for Treating Symptomatic PersistenT AF) study was conducted at 27 sites in the United States and Canada. Enrollment criteria included documented symptomatic PsAF and nonresponse or intolerance to ≥1 antiarrhythmic drug (Class I or III). An individualized treatment approach was used including pulmonary vein isolation with ablation of additional targets permitted at the investigators' discretion. To optimize treatment outcomes, a 3-month post-ablation medication adjustment period followed by a 3-month therapy consolidation period were included. Arrhythmia recurrences were stringently monitored by monthly and symptomatic transtelephonic monitoring, electrocardiography, and Holter monitoring for up to 15 months after ablation.Of 381 enrolled participants, 348 had the investigational catheter inserted and underwent ablation. The primary adverse event rate was 4.1% (15 events in 14 participants). Kaplan-Meier analyses estimated a primary effectiveness success rate of 61.7% and a clinical success rate of 80.4% at 15 months.The results demonstrate the clinical safety and effectiveness of PsAF ablation using contact force-sensing technologies. The primary adverse event was within the expected range and similar to those reported in historical studies of paroxysmal AF ablation. (Prospective Review of the Safety and Effectiveness of the THERMOCOOL SMARTTOUCH SF Catheter Evaluated for Treating Symptomatic PersistenT AF; NCT02817776).

Aims THERMOCOOL SMARTTOUCH® SF Catheter is a new contact-force (CF)-sensing catheter with 56-hole porous tip designed for improved cooling and reduced fluid delivery compared with a standard 6-hole open-irrigated catheter. The SMART SF study examined the periprocedural safety, acute effectiveness, and procedural efficiency of the catheter for drug-refractory symptomatic paroxysmal atrial fibrillation (PAF) ablation. Methods and results The prospective, open-label, non-randomized SMART-SF was conducted at 17 US sites. Circumferential pulmonary vein (PV) isolation was performed with confirmation of entrance block in all PVs. Stable ablation sites were identified using CARTO VISITAG™ Module. Primary adverse events (AEs; ≤1 week of index procedure), periprocedural AEs within 30 days of ablation procedure, acute effectiveness (confirmation of entrance block for targeted PVs), CF, and procedural parameters were assessed. Overall, 165 patients were enrolled (mean age, 62.7 years; male, 57.9%; white, 97%; left ventricular ejection fraction, 60.1 ± 7%; left atrium diameter, 38.8 ± 6 mm); 159 underwent radiofrequency ablation and comprised the safety cohort. Primary safety performance criteria were met: primary AE rate was 2.5% (4/159; cardiac tamponade [n = 2], thrombo-embolism [n = 1], transient ischaemic attack [n = 1]). All primary AEs resolved/improved within the 1-month follow-up period. Acute procedural effectiveness was attained in 96.2% (95% confidence interval: 92.0-98.6%) of patients. Procedure time, fluoroscopy time, and fluid delivered were observed in comparison to predecessor catheters. Conclusion In the SMART-SF trial, the predetermined safety performance goal was met, demonstrating the safety and acute effectiveness of the THERMOCOOL SMARTTOUCH® SF Catheter for PAF ablation.

Background Recent economic trends influenced by healthcare reform, an aging population, changes in physician reimbursement, and increasing competition will have a significant impact on the electrophysiology workforce. Therefore, there is an important need to obtain information about the EP workforce to assess training of arrhythmic healthcare providers in order the meet the requisite societal need. This report summarizes the data collected by the HRS Workforce Study Task Force in relation to physician workforce issues. Objective The HRS Workforce Study Task Force was charged with conducting a comprehensive study to assess changes in the field of electrophysiology since the last workforce study conducted in 2001 and to identify the population and distribution of professionals who treat patients with heart rhythm disorders. Methods A series of comprehensive questionnaires were designed by the HRS Workforce Study Task Force to conduct online surveys with physicians, basic science researchers, and allied professionals. Data collected in the physician survey included: personal demographics and professional profile characteristics such as primary work setting and areas of affiliation; workload characteristics such as hours worked, time spent by activity, workload relative to capacity, competition for patients, volume by specific procedure, sources of referrals, income levels, personal mobility, and anticipated future changes in the respondent's practice. Survey responses were collated and analyzed by the Workforce Study Task Force. Results Work capacity is expected to increase to offset some of the economic drivers; however, recruitment of new EPs could be challenging and uncertain. Specifically, geographic mobility (>50 miles) appears to be minimal at present overall and unlikely to significantly change for the majority of physicians once they have established themselves in a given community following the completion of their training. Practice time is predominantly spent performing device implantations, device follow-ups and ablations. These activities are being tasked upon younger physicians, thereby suggesting a need for trained allied professionals to assume a greater role in device management. The perception of competition varied by respondent age and geographic location but, in general, was felt to be at least moderate by most respondents. Furthermore, there are concerns that increasing competition may dilute operator experience and potentially lower high quality outcomes if increasing competition leads to lower procedural volumes. Conclusion Based on findings from this study, the task force identified specific workforce (supply) trends and the key drivers of current and future challenges. Although specific areas will require further analysis, overall, the current EP workforce is stable, with the exception of geographic dispersion. However, the workforce must adapt to the key economic drivers (demand) and address future recruitment challenges.

In the present study we determined the long-term effects of persistent, local insulin-like growth factor I (IGF-I) expression on cardiac function in the SIS2 transgenic mouse. Cardiac mass/tibial length was increased in SIS2 mice by 10 wk of age; this cardiac hypertrophy became more pronounced later in life. Peak aortic outflow velocity, a correlate of cardiac output, was increased at 10 wk in SIS2 mice but was decreased at 52 wk. 72 wk SIS2 mouse hearts exhibited wide variability in the extent of cardiac hypertrophy and enlargement of individual cardiac myofibers. Sirius red staining revealed increased fibrosis in 72 wk SIS2 hearts. Persistent local IGF-I expression is sufficient to initially induce an analog of physiological cardiac hypertrophy in which peak aortic outflow velocity is increased relative to controls in the absence of any observed detrimental histological changes. However, this hypertrophy progresses to a pathological condition characterized by decreased systolic performance and increased fibrosis. Our results confirm the short-term systolic performance benefit of increased IGF-I, but our demonstration that IGF-I ultimately diminishes systolic performance raises doubt about the therapeutic value of chronic IGF-I administration. Considering these findings, limiting temporal exposure to IGF-I seems the most likely means of delivering IGF-I's potential benefits while avoiding its deleterious side effects.

Recent studies suggest that RhoA and Rac1 mediate hypertrophic signals in cardiac myocyte hypertrophy. However, effects on cardiac function caused by inhibition of their activity in the heart have yet to be evaluated. Cardiac-specific inhibition of Rho family protein activities was achieved by expressing Rho GDIalpha, an endogenous specific GDP dissociation inhibitor for Rho family proteins, using the alpha-myosin heavy-chain promoter. Increased expression of Rho GDIalpha led to atrial arrhythmias and mild ventricular hypertrophy in adult mice (4-7 months). However, left ventricular systolic and diastolic function was largely preserved before and after the development of cardiac hypertrophy, indicating that Rho GTPases are not required to maintain ventricular contractile function under basal physiological condition. Electrocardiography and intracardiac electrophysiological studies revealed first-degree atrioventricular (AV) block in the transgenic heart at 1 week of age, which further progressed into second-degree AV block at 4 weeks of age before the development of cardiac hypertrophy. Expression of connexin 40 dramatically decreased from 1 week to 4 weeks of age in the transgenic heart, which may contribute in part to the conduction defects in the transgenic mice. This study provides novel evidence for an important role of Rho GTPases in regulating AV conduction.

Adult transgenic mice with muscle-specific overexpression of insulin-like growth factor (IGF)-I have enlarged skeletal muscles. In this study, we; 1) characterized the development of muscle hypertrophy with respect to fiber type, age, and sex; 2) determined the primary anabolic process responsible for development of hypertrophy; and 3) identified secondary effects of muscle hypertrophy on body composition. Transgene expression increased with age and was present only in fibers expressing type IIB fast myosin heavy chain. Muscle masses were greater by 5 wk of age, and by 10 wk of age the differences were maximal despite continued transgene expression. Total DNA and RNA contents of the gastrocnemius muscle were greater for transgenic mice than for nontransgenic littermates. The differences were maximal by 5 wk of age and preceded the increase in protein mass. The accelerated protein deposition ceased when the protein/DNA ratio attained the same value as in nontransgenic controls. Despite localization of IGF-I expression to muscle without changes in plasma IGF-I concentrations, genotype also modified the normal age and sex effects on fat deposition and organ growth. Thus, enhanced DNA accretion by IGF-I was primarily responsible for stimulating muscle growth. In turn, secondary effects on body composition were incurred that likely reflect the impact of muscle mass on whole body metabolism.