Search

The potential risk of embolic events during ablation in the left ventricle (LV) with a heated saline–enhanced radiofrequency (SERF) needle-tip ablation catheter has not been characterized. This study aimed to investigate the formation of microemboli or other untoward events during SERF ablation. Ninety-three radiofrequency (RF) ablation procedures were performed in the LV of 14 pigs by using a SERF catheter (35 W, 70 seconds, and 60°C; normal or degassed saline [NS or DS] irrigation with a flow rate of 10 mL/min) vs a standard irrigated-tip radiofrequency (S-RF) catheter (30 or 50 W, 30 seconds, and 17 mL/min). Microbubble formation was graded on the basis of intracardiac echocardiography. Microbubbles, microembolic signals, and microparticles were monitored using our established model. There was no significant difference in microbubble volume among SERF-NS, SERF-DS, and S-RF 30 W with "grade 1" intracardiac echocardiography microbubbles (median and 25th–75th percentiles 0.201 [0.011–3.13], 0.455 [0.06–2.66], and 0.004 μL [0.00–0.16 μL], respectively). There was no significant difference in microembolic signals among SERF-NS, SERF-DS, and S-RF 30 W with grade 1 bubbles (n = 8.0 ± 5.8, n = 7.6 ± 4.2, and n = 6.1 ± 6.1, respectively). Both SERF-NS and SERF-DS created larger lesions than did both S-RF 30 W and S-RF 50 W deliveries (mean 1241.5 ± 658.6, 1497.7 ± 893.4, 75.0 ± 24.8, and 184.0 ± 93.8 mm3; P <.001). There was no significant difference in microparticle incidence among groups (P =.675). No evidence of embolic events was found in the brain and other organs at the histology assessment. In the setting of SERF ablation, significantly large LV lesions can be created without any increment in embolic microbubble or particle events. Grade 1 microbubble is related to the efficacy and safety. [Display omitted] [ABSTRACT FROM AUTHOR]

The finding of unexpected variations in treatment benefits by geographic region in international clinical trials raises complex questions about the interpretation and generalizability of trial findings. We observed such geographical variations in outcome and in the effectiveness of atrial fibrillation (AF) ablation versus drug therapy in the Catheter Ablation vs Antiarrhythmic Drug Therapy for Atrial Fibrillation (CABANA) trial. This paper describes these differences and investigates potential causes. The examination of treatment effects by geographic region was a prespecified analysis. CABANA enrolled patients from 10 countries, with 1,285 patients at 85 North American (NA) sites and 919 at 41 non-NA sites. The primary endpoint was a composite of death, disabling stroke, serious bleeding, or cardiac arrest. Death and first atrial fibrillation recurrence were secondary endpoints. At least 1 primary endpoint event occurred in 157 patients (12.2%) from NA and 33 (3.6%) from non-NA sites over a median 54.9 and 40.5 months of follow-up, respectively (NA/non-NA adjusted hazard ratio (HR) 2.18, 95% confidence interval (CI) 1.48-3.21, P <.001). In NA patients, 78 events occurred in the ablation and 79 in the drug arm, (HR 0.91, 95% CI 0.66, 1.24) while 11 and 22 events occurred in non-NA patients (HR 0.51, 95% CI 0.25,1.05, interaction P =.154). Death occurred in 53 ablation and 51 drug therapy patients in the NA group (HR 0.96, 95% CI 0.65,1.42) and in 5 ablation and 16 drug therapy patients in the non-NA group (HR 0.32, 95% CI 0.12,0.86, interaction P =.044). Adjusting for baseline regional differences or prognostic risk variables did not account for the regional differences in treatment effects. Atrial fibrillation recurrence was reduced by ablation in both regions (NA: HR 0.54, 95% CI 0.46, 0.63; non-NA: HR 0.44, 95% CI 0.30, 0.64, interaction P =.322). In CABANA, primary outcome events occurred significantly more often in the NA group but assignment to ablation significantly reduced all-cause mortality in the non-NA group only. These differences were not explained by regional variations in procedure effectiveness, safety, or patient characteristics. ClinicalTrials.gov Identifier: NCT0091150; https://clinicaltrials.gov/study/NCT00911508 [ABSTRACT FROM AUTHOR]

Freedom from atrial arrhythmia (AA) recurrence ≥30 seconds after pulsed field ablation (PFA) in patients with atrial fibrillation (AF) was reported in PULSED AF (Pulsed Field Ablation to Irreversibly Electroporate Tissue and Treat AF; ClinialTrials.gov Identifier: NCT04198701). AA burden may be a more clinically meaningful endpoint. The purpose of this study was to determine the influence of monitoring strategies on AA detection and AA burden association with quality of life (QoL) and health care utilization (HCU) after PFA. Patients underwent 24-hour Holter monitoring at 6 and 12 months and weekly, and symptomatic transtelephonic monitoring (TTM). AA burden post-blanking was calculated as the greater of (1) percentage of AA on total Holter time; or (2) percentage of weeks with ≥1 TTM with AA out of all weeks with ≥1 TTM. Freedom from all AAs varied by >20% when differing monitoring strategies were used. PFA resulted in zero burden in 69.4% of paroxysmal atrial fibrillation (PAF) and 62.2% of persistent atrial fibrillation (PsAF) patients. Median burden was low (<9%). Most PAF and PsAF patients had ≤1 week of AA detection on TTM (82.6% and 75.4%) and <30 minutes of AA per day of Holter monitoring (96.5% and 89.6%), respectively. Only PAF patients with <10% AA burden averaged a clinically meaningful (>19 point) QoL improvement. PsAF patients experienced clinically meaningful QoL improvements irrespective of burden. Repeat ablations and cardioversions significantly increased with higher AA burden (P <.01). The ≥30-second AA endpoint is dependent on the monitoring protocol used. PFA resulted in low AA burden for most patients, which was associated with clinically relevant improvement in QoL and reduced AA-related HCU. [ABSTRACT FROM AUTHOR]

There are many challenges in the current landscape of electrophysiology (EP) clinical and translational research, including increasing costs and complexity, competing demands, regulatory requirements, and challenges with study implementation. This review seeks to broadly discuss the state of EP research, including challenges and opportunities. Included here are results from a Heart Rhythm Society (HRS) Research Committee member survey detailing HRS members' perspectives regarding both barriers to clinical and translational research and opportunities to address these challenges. We also provide stakeholder perspectives on barriers and opportunities for future EP research, including input from representatives of the U.S. Food and Drug Administration , industry, and research funding institutions that participated in a Research Collaboratory Summit convened by HRS. This review further summarizes the experiences of the heart failure and heart valve communities and how they have approached similar challenges in their own fields. We then explore potential solutions, including various models of research ecosystems designed to identify research challenges and to coordinate ways to address them in a collaborative fashion in order to optimize innovation, increase efficiency of evidence generation, and advance the development of new therapeutic products. The objectives of the proposed collaborative cardiac EP research community are to encourage and support scientific discourse, research efficiency, and evidence generation by exploring collaborative and equitable solutions in which stakeholders within the EP community can interact to address knowledge gaps, innovate, and advance new therapies. [ABSTRACT FROM AUTHOR]

Background: Cryoballoon ablation (CBA) as a first-line rhythm control strategy is superior to antiarrhythmic drugs (AADs) for preventing atrial fibrillation (AF) recurrence; the impact of first-line CBA on quality of life (QoL) and symptoms has not been well characterized.Methods: Patients aged 18 to 75 with symptomatic paroxysmal AF naïve to rhythm control therapy were randomized (1:1) to CBA (Arctic Front Advance, Medtronic) or AAD (Class I or III). Symptoms and QoL were assessed at baseline, 1, 3, 6, 9, and 12 months using the EHRA classification and Atrial Fibrillation Effect on QualiTy-of-Life (AFEQT) and SF-36v2 questionnaires. Symptomatic palpitations were evaluated via patient diary.Results: Overall, 107 patients were randomized to CBA and 111 to AAD; crossovers occurred in 9%. Larger improvements in the AFEQT summary, subscale and treatment satisfaction scores were observed at 12 months with CBA vs AAD (all P <0.05). At 12 months, the mean adjusted difference in the AFEQT summary score was 9.9 points higher in the CBA group (95% CI: 5.5 -14.2, P <0.001). Clinically important improvements in the SF-36 physical and mental component scores were observed at 12 months in both groups, with no significant between group differences at this timepoint. In the CBA vs AAD group, larger improvements in EHRA class were observed at 6, 9 and 12 months (P <0.05) and the incidence rate of symptomatic palpitations was lower (4.6 vs 15.2 days/year post-blanking; IRR: 0.30, P <0.001).Conclusions: In patients with symptomatic AF, first-line CBA was superior to AAD for improving AF-specific QoL and symptoms.Trial Registration: ClinicalTrials.gov number: NCT01803438. [ABSTRACT FROM AUTHOR]

Background: Recurrent arrhythmia following catheter ablation of atrial fibrillation (AF) may present early, during a standard 3-month blanking period. Early recurrence has been correlated to late recurrence, but the degree to which its absence predicts longer-term success has not been quantified.Objective: The purpose of this study was to explore and quantify the relationship between early and late arrhythmia recurrence, specifically the negative predictive value, that is, the degree to which absence of blanking period recurrence predicts absence of late recurrence.Methods: A systematic literature review and meta-analysis were conducted using statistical methods of a diagnostic test accuracy review. Studies of AF ablation using point-by-point radiofrequency, with repeated monitoring of arrhythmia recurrence including asymptomatic recurrence, and with separate data by AF type, were eligible.Results: Nine studies met the prespecified eligibility criteria. For paroxysmal AF, 89% (confidence interval [CI] 82%-94%) of patients free from early recurrence remained free from late recurrence. The estimate for persistent AF was similar (91%; CI 75%-97%). This finding was robust in sensitivity analyses. Patients with early recurrence had a wider range of likely outcomes with longer-term follow-up.Conclusion: Freedom from AF recurrence during the blanking period is highly predictive of longer-term success in catheter ablation. Clinical trials in this area may be able to leverage these findings to more quickly assess the potential utility of new ablation technologies and methods, for example, by using early surrogate measures of success. [ABSTRACT FROM AUTHOR]

Background: Irrigated needle catheter ablation is efficacious for creation of transmural lesions in the left ventricle (LV). However, interdependence of needle orientation and myocardial fiber orientation and the resulting influence on lesion creation remain unclear.Objective: The purpose of this study was to investigate the impact of myocardial fiber orientation on reproducibility and controllability of lesion creation in LV myocardium using a heated saline-enhanced radiofrequency (SERF) needle-tip catheter system.Methods: Eleven dogs underwent catheter ablation using this novel catheter. Ablative lesions were created using different power and ablation times (15-50 W; application 25-120 seconds; 60°C irrigation saline at 10 mL/min). Hearts were explanted, and lesions were evaluated using 3-T cardiac magnetic resonance (CMR), gross pathologic, and histologic investigations.Results: Forty-three of 57 lesions (75.4%) were transmural, and lesion depth reached approximately 90% of LV wall thickness. Lesion volume in both gross pathology and ex vivo CMR showed a positive linear correlation with power × radiofrequency (RF) time index (r = 0.637, P <.001; and r = 0.786, P <.001, respectively). Maximum width (circumferential direction of LV) and maximum length (long-axis direction) of all lesions were distributed in the middle layer of LV where myocardium runs circumferentially. Paired-sample t-test showed maximum lesion width was significantly greater than maximum lesion length by both CMR and gross pathologic evaluation (26.1 ± 9.6 mm vs 17.2 ± 6.7 mm, P <.001; and 22.5 ± 7.7 mm vs 18.6 ± 5.9 mm, P <.001, respectively).Conclusion: This catheter showed feasibility in creating transmural LV lesions. Power × RF time index was strongly correlated with lesion volume and predicted lesion size. More importantly, SERF lesions extended along the myocardial fiber orientation. [ABSTRACT FROM AUTHOR]

Background: Scar-related ventricular arrhythmias are common after myocardial infarction. Catheter ablation can improve prognosis, but the procedure is invasive and results are not always satisfactory. Noninvasive, catheter-free ablation using ionizing radiation has recently gained interest among electrophysiologists, but the tissue effects and physiological outcome have not been fully characterized.Objective: The purpose of this study was to investigate the structural effects of cardiac scanned pencil beam proton therapy on infarct scar, the time course of imaging biomarkers, arrhythmias, and cardiac function in a porcine model.Methods: Fourteen infarcted swine underwent proton beam treatment of the scar (40 or 30 Gy) and were followed for up to 30 weeks. Magnetic resonance imaging was performed every 4 weeks.Results: Treated scar areas showed a significantly lower fraction of surviving myocytes at 30 weeks compared to untreated scar (30.1% ± 18.5% and 59.9% ± 10.1% in treated and untreated infarct, respectively), indicating scar homogenization. Four animals died suddenly during follow-up, all from documented monomorphic ventricular tachycardia. Cardiac function remained stable over the course of the study. Distinct imaging morphologies corresponded to certain tissue dose ranges and time points.Conclusion: Radioablation of cardiac infarct scar leads to significant homogenization of the scar, replicating the histologic effects of radiofrequency ablation. These changes correspond to distinct imaging morphologies on delayed contrast-enhanced cardiac magnetic resonance imaging, enabling noninvasive confirmation of tissue ablation effects The present study is the first to thoroughly investigate the structural effects of cardiac proton beam therapy in infarcted myocardium. [ABSTRACT FROM AUTHOR]

Background: The cryoballoon (CB) catheter is an established tool for pulmonary vein isolation (PVI), but its use is limited for that purpose.Objective: The purpose of this study was to investigate the biophysical properties of a newly developed linear cryoablation catheter for creation of linear ablation lesions in an in vivo model.Methods: Twenty-nine dogs (14 acutely ablated, 15 chronically followed) underwent cryoablation using the linear cryoablation catheter. Regions of interest included the cavotricuspid isthmus (CTI), mitral isthmus (MI), left atrial (LA) roof, and LA posterior wall in an acute study. Cryoablations for CTI and MI were performed in 14 atrial fibrillation animals after PVI and followed over 1 month in the chronic study. Tissue temperature during cryoablation was monitored using implanted thermocouples in the regions of interest. Gross and microscopic pathologic characteristics of the lesions were assessed.Results: In acute animals, lesion length (transmurality) was CTI 34 ± 4 mm (89% ± 11%); MI 29 ± 4 mm (90% ± 13%); LA roof 19 ± 3 mm (90% ± 8%); and LA posterior wall 19 ± 2 mm (81% ± 13%), with 1 or 2 freezes. Chronic bidirectional block was achieved in 13 of 14 CTI (93%) and 10 of 14 MI (71%) ablations after 1-month follow-up and was consistent with lesion continuity and transmurality upon pathology. The lowest tissue temperature correlated well with the closest distance to the linear cryocatheter (r = 0.688; P <.001).Conclusion: This linear cryocatheter created continuous and transmural linear lesions with "single-shot" cryoenergy application and has the potential for clinical use in the setting of various arrhythmias. [ABSTRACT FROM AUTHOR]

Background: In the Catheter Ablation for Atrial Fibrillation with Heart Failure (CASTLE-AF) trial, catheter ablation reduced the risk of death and heart failure (HF) hospitalization in patients with atrial fibrillation and HF by 40%.Objectives: The study aimed to assess the generalizability of CASTLE-AF to routine clinical practice.Methods: Using a large US administrative database, we identified 289,831 patients with atrial fibrillation and HF treated with ablation (n = 7465) or medical therapy alone (n = 282,366) from January 1, 2008, through August 31, 2018. Patients were divided into 3 groups on the basis of trial eligibility: (1) eligible for CASTLE-AF, (2) failing to meet the inclusion criteria, and (3) meeting at least 1 of the exclusion criteria. Propensity score overlap weighting was used to balance ablated and drug-treated patients on 90 baseline characteristics. Cox proportional hazards regression was used to compare ablation with medical therapy for the primary outcome of a composite end point of all-cause mortality and HF hospitalization.Results: Only 7.8% of patients would have been eligible for the trial; 91.0% failed to meet the trial inclusion criteria; and 15.5% met the exclusion criteria. Ablation was associated with a lower risk of the primary outcome in the overall cohort (hazard ratio [HR] 0.81; 95% confidence interval [CI] 0.76-0.87; P < .001), in the trial-eligible cohort (HR 0.82; 95% CI 0.70-0.96; P = .01), and in patients who failed to meet inclusion criteria (HR 0.79; 95% CI 0.73-0.86; P < .001) but not in patients who met the exclusion criteria (HR 0.97; 95% CI 0.81-1.17). The relative risk reduction was consistent regardless of whether patients had HF with reduced left ventricular ejection fraction.Conclusion: The benefit associated with ablation appears to be more modest in practice than that reported in the CASTLE-AF trial. [ABSTRACT FROM AUTHOR]

Background: Radiofrequency current (RFC) catheter ablation for patients with paroxysmal atrial fibrillation (AF) has been shown to be safe and effective in first-line therapy. Recent data demonstrates that RFC ablation provides better clinical outcomes compared to antiarrhythmic drug (AAD) in the treatment of early AF disease. Furthermore, studies comparing RFC and cryoballoon have established comparable efficacy and safety of pulmonary vein isolation (PVI) for patients with symptomatic paroxysmal AF.Objectives: The Cryo-FIRST trial was designed to compare AAD treatment against cryoballoon PVI as a first-line therapy in treatment naïve patients with AF. Efficacy and safety will be compared between the two cohorts and amongst subgroups.Methods: The primary hypothesis is that cryoablation is superior to AAD therapy. To test this hypothesis, patients will be randomized in a 1:1 design. Using a 90-day blanking period, primary efficacy endpoint failure is defined as (at least) one episode of atrial arrhythmia with a duration >30 sec (documented by 7-day Holter or 12-lead ECG). Secondary endpoints (Quality-of-Life, rehospitalization, arrhythmia recurrence rate, healthcare utilization, and left atrial function) and adverse events will also be evaluated. Study enrollment will include 218 patients in up to 16 centers.Conclusions: This study will be a multi-national randomized controlled trial comparing cryoablation against AAD as a first-line treatment in patients with paroxysmal AF. The results may help guide the selection of patients for early AF disease therapy via cryoballoon ablation. [ABSTRACT FROM AUTHOR]

Background: Noninvasive cardiac ablation of ventricular tachycardia (VT) using radiotherapy has recently gained interest among electrophysiologists. The effects of left ventricular (LV) ablative radiation treatment on global LV function and volumes are unknown.Objective: The purpose of this study was to investigate the effects of noninvasive ablation on LV function over time.Methods: Twenty domestic swine underwent proton beam treatment of LV sites in a dose-finding design and were followed for up to 40 weeks by cardiac magnetic resonance imaging at 4-week intervals. Doses investigated were either 40 Gy at 1 site (n = 8) or 30 Gy at 2 sites (n = 4) in the low-dose group and 40 Gy at 3 sites (n = 8) in the high-dose group.Results: LV mean dose (13.2 ± 1.8 Gy vs 4.6 ± 1.8 Gy) and the volume receiving at least 20 Gy (V20Gy) (24.7% ± 4.8% vs 6.4% ± 3.0%) differed significantly between groups. Dose-dependent effects on left ventricular ejection fraction (LVEF) and LV end-diastolic volume became manifest about 3 months after treatment. LVEF decline was correlated to mean dose (correlation coefficient ρ = -0.69; P = .008) and V20Gy (ρ = -0.66; P = .01), as was LV dilation (ρ = 0.72; P = .005; and ρ = 0.75, P = .003 respectively).Conclusion: Possible adverse effects on LV function, seen about 3 months after treatment, are dose dependent. Therefore, precise target definition and focused energy delivery are paramount in catheter-free ablation. [ABSTRACT FROM AUTHOR]

The Catheter Ablation Versus Anti-arrhythmic Drug Therapy for Atrial Fibrillation (CABANA,NCT00911508)(1) trial is testing the hypothesis that the treatment strategy of percutaneous left atrial catheter ablation for the purpose of eliminating atrial fibrillation (AF) is superior to current state-of-the-art pharmacologic therapy. This international 140-center clinical trial was designed to randomize 2200 patients to a strategy of catheter ablation versus state-of-the-art rate or rhythm control drug therapy. Inclusion criteria include: 1) age> 65, or ≤65 with≥ 1 risk factor for stroke, 2) documented AF warranting treatment, and 3) eligibility for both catheter ablation and≥ 2 anti-arrhythmic or≥ 2 rate control drugs. Patients were followed every 3 to 6 months (median 4 years) and underwent repeat trans-telephonic monitoring, Holter monitoring, and CT/MR in a subgroup of patient studies to assess the impact of treatment on AF recurrence and atrial structure. With 1100 patients in each treatment arm, CABANA is projected to have 90% power for detecting a 30% relative reduction in the primary composite endpoint of total mortality, disabling stroke, serious bleeding, or cardiac arrest. Secondary endpoints include total mortality; mortality or cardiovascular hospitalization; a combination of mortality, stroke, hospitalization for heart failure or acute coronary artery events; cardiovascular death alone; and heart failure death, as well as AF recurrence, quality of life, and cost effectiveness. At a time when AF incidence is rising rapidly, CABANA will provide critical evidence with which to guide therapy and shape health care policy related to AF for years to come. [ABSTRACT FROM AUTHOR]

Introduction Whereas hadron therapy of static targets is clinically established, treatment of moving organs remains a challenge. One strategy is to minimize motion of surrounding tissue mechanically and to mitigate residual motion with an appropriate irradiation technique. In this technical note, we present and characterize such an immobilization technique for a novel noncancerous application: the irradiation of small targets in hearts with scanned carbon ion beams in a porcine model for elimination of arrhythmias. Material and methods A device for immobilization was custom-built. Both for the treatment planning 4D-CT scan and for irradiation, breath-hold at end-exhale was enforced using a remotely-controlled respirator. Target motion was thus reduced to heartbeat only. Positioning was verified by orthogonal X-rays followed by couch shift if necessary. Reproducibility of bony anatomy, diaphragm, and heart position after repositioning and between repeated breath-hold maneuvers was evaluated on X-rays and cardiac-gated 4D-CTs. Treatment was post hoc simulated on sequential 4D-CTs for a subset of animals, after immediate repositioning and after a delay of one week, similar to the delay between imaging and irradiation. Results Breath-hold without repositioning was highly reproducible with an RMS deviation of at most one millimeter. 4D-CTs showed larger deformations in soft tissue, but treatment simulation on sequential images resulted in full target coverage (V95 >95%). Conclusion The method of immobilization permitted reproducible positioning of mobile, thoracic targets for range-sensitive particle therapy. The presented immobilization strategy could be a reasonable approach for future animal investigations with the ultimate goal of translation to therapy in men. [ABSTRACT FROM AUTHOR]

Background: Repaired congenital heart disease (rCHD) is strongly associated with ventricular tachycardia (VT) as an important late cause of morbidity and mortality. Ventricular reentry most commonly includes anatomic isthmuses created during the repair procedures.Objective: The purpose of this study was to analyze the long-term outcomes of catheter ablation, a commonly used standalone or adjunctive therapy, in a cohort of rCHD patients.Methods: A retrospective analysis of 21 consecutive patients with rCHD (45.0 ± 3.0 years, 71.4% male) undergoing ablation for VT was performed. The primary composite outcome was defined as in-hospital arrhythmic death, out-of-hospital sudden cardiac death, or appropriate implantable cardioverter-defibrillator therapy.Results: At initial electrophysiologic study, 14 patients (66.7%) had reentrant VT through an electroanatomic isthmus; the remaining 7 patients (33.3%) demonstrated focal VT. Isthmus-dependent reentry was identified as the mechanism for VT in 14 patients (66.7%), and conduction block was confirmed in 8 of these patients (57.1%). No patients with confirmed block developed VT recurrence. During long-term follow-up (33 ± 7 months), 20 of 21 patients (95.2%) had not reached the primary composite outcome. Three patients died of nonarrhythmic causes.Conclusion: Catheter-based VT ablation in patients with rCHD is associated with a low rate of VT recurrence. Focal VT was not uncommon in this cohort. If a reentrant mechanism is present, confirmation of conduction block across the isthmus is vital to prevent recurrence. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation (AF) ablation is superior to pharmacologic therapy in achieving maintenance of normal sinus rhythm in selected patient populations. However, the procedure is resource intensive, and repeat ablations are sometimes required. We examined the predictors and trends of repeat ablation using a large national administrative claims database.Methods: Privately insured and Medicare Advantage patients who underwent catheter ablation for AF between January 1, 2004, and September 30, 2014, were included in the study. The primary outcome was repeat AF ablation during enrollment. We examined the associations between repeat ablation and patient demographics (age, gender, socioeconomic demographics), comorbid conditions (CHA2DS2-Vasc score and Charlson index), and year of the index ablation. Cox proportional hazard models were used to identify predictors of repeat ablation.Results: We included 8,648 adult patients in the analysis. Median age was 61.0 (interquartile range [IQR] 54-68) years, and 70.9% were men. Median follow-up was 1.1 (IQR 0.5-2.3) years. A total of 1,263 patients underwent repeat ablation (14.6%) over a total of 14,280 person-years (12.1% at 1 year). The hazard ratio (HR) for repeat ablation was higher in younger patients (HR 0.75 [0.61-0.91; P < .01] for age 65-75 and 0.55 [0.4-0.75; P < .001] for age ≥ 75 compared with age 18-54), those with higher household income (HR 1.24 [1-1.54; P < .05] for household income ≥ $100,000 compared with household income < $40,000), patients treated in the south (HR 1.15 [1-1.31]; P < .05), and those on antiarrhythmic medications (HR 1.15 [1.01-1.31]; P < .05). In particular, younger patients (ages 18-54 years) continued to undergo repeat ablations over the entire follow-up period, and the cumulative rate was approximately 40% among those followed for 5 years. Clinical characteristics including those included in the CHA2DS2-Vasc score and Charlson index did not predict likelihood of repeat ablation. The rate of repeat ablation remained constant over the available follow-up.Conclusion: Approximately 1 in 8 patients treated with catheter ablation for AF will undergo a second procedure within 1 year, although the rate is as high as 40% in young patients at 5 years. The rate of repeat ablation appears to be associated with demographic characteristics (younger age and higher household income) rather than medical comorbidities. [ABSTRACT FROM AUTHOR]

Unlabelled: As the number of patients undergoing catheter ablation for atrial fibrillation (AF) increases, there is a growing focus on optimizing the quality and efficiency of. Readmission is often considered an indicator of both quality and efficiency of care delivery. We sought to estimate rates and identify predictors of readmission after catheter ablation.Methods and Results: Using a large, national administrative claims database, we identified all AF patients who underwent catheter ablation between January 2009 and December 2013 (10,705 ablation cases). We examined incident readmission and the primary diagnosis during the readmission episode of care. We used Cox proportional hazard models to identify associations between readmission and patient and institutional characteristics. A total of 1,433 (13.4%) ablation patients were readmitted within 90 days of ablation for any cause, and 573 (5.4%) were admitted with AF as the primary diagnosis. There was a decline in all-cause (from 15.6% to 12.8%; P = .04) and AF-related (6.4%-5.0 %; P = .03) 90-day readmission over the study period. In a multivariate model, earlier year of ablation and each of 9 chronic conditions (alone or in combination) were independently associated with risk of readmission.Conclusions: Between 2009 and 2013, there was a reduction in 90-day readmission rates after AF ablation, suggesting improved periprocedural care of these patients. Identifying patients at high risk for readmission after catheter ablation for AF may offer an opportunity for early intervention and, ultimately, reduction in procedural morbidity and medical costs. [ABSTRACT FROM AUTHOR]

Background Stroke is the major cause of morbidity and mortality related to atrial fibrillation (AF). Catheter ablation for AF is effective in reducing AF burden, but its impact on long-term stroke risk is unknown. Objective We sought to evaluate the periprocedural and long-term stroke risk after catheter ablation or cardioversion for AF. Methods This retrospective, propensity-matched study using a national administrative claims database identified patients with AF who underwent catheter ablation and a comparison group (matched on age, sex, year of treatment, CHA 2 DS 2 -Vasc score, and Charlson index) who underwent cardioversion between 2005 and 2012. The primary end points were (1) time to first ischemic or hemorrhagic stroke or transient ischemic attack (TIA) and (2) time to first ischemic or hemorrhagic stroke excluding TIA. We compared periprocedural incident stroke (within 30 days of ablation or cardioversion) as well as total strokes between the 2 groups. Results A total of 24,244 patients (12,122 patients undergoing ablation and 12,122 patients undergoing cardioversion) were included in the analysis. Incident periprocedural stroke or TIA occurred in 0.5% of the ablation group and 0.3% of the cardioversion group ( P = .04). There was a significant initial risk of stroke/TIA with ablation within the first 30 days (rate ratio 1.53; P = .05). After 30 days, this risk was significantly lower in the ablation group (rate ratio 0.78; P = .03). Conclusion In patients with AF, there is a small periprocedural stroke risk with ablation in comparison to cardioversion. However, over longer-term follow-up, ablation is associated with a slightly lower rate of stroke. [ABSTRACT FROM AUTHOR]

Background: It is unknown whether radiofrequency ablation (RFA) or antiarrhythmic therapy is superior when treating patients with symptomatic premature ventricular contractions (PVCs). Objective: To determine the relative efficacy of RFA and antiarrhythmic drugs (AADs) on PVC burden reduction and increasing left ventricular systolic function. Methods: Patients with frequent PVCs (>1000/24 h) were treated either by RFA or with AADs from January 2005 through December 2010. Data from 24-hour Holter monitoring and echocardiography before and 6–12 months after treatment were compared between the 2 groups. Results: Of 510 patients identified, 215 (40%) underwent RFA and 295 (60%) received AADs. The reduction in PVC frequency was greater by RFA than with AADs (–21,799/24 h vs –8,376/24 h; P < .001). The left ventricular ejection fraction (LVEF) was increased significantly after RFA (53%–56%; P < .001) but not after AAD (52%– 52%; P = .6) therapy. Of 121 (24%) patients with reduced LVEF, 39 (32%) had LVEF normalization to 50% or greater. LVEF was restored in 25 of 53 (47%) patients in the RFA group compared with 14 of 68 (21%) patients in the AAD group (P = .003). PVC coupling interval less than 450 ms, less impaired left ventricular function, and RFA were independent predictors of LVEF normalization performed by using multivariate analysis. Conclusion: RFA appears to be more effective than AADs in PVC reduction and LVEF normalization. [Copyright &y& Elsevier]

Background: With the increasing use, complexity, anatomical approaches, and tools related to epicardial procedures, complications previously not seen during endovascular ablation are now well recognized with epicardial ablation. Whether newer approaches and the regional anatomy of the pericardial space contribute to unexpected complications after epicardial access (EpiAcc) is presently unknown. Objective: To characterize underreported, or novel, complications associated with percutaneous EpiAcc as part of an electrophysiology procedure. Methods: We retrospectively reviewed percutaneous EpiAcc as part of an ablation procedure from January 1, 2004, to December 31, 2011. Results: Of 116 attempts in 107 patients, 8 atypical ablation complications (no procedural deaths) were noted; complications included delayed pericarditis (2 weeks), chronic refractory pericarditis, requirement for snaring of broken intrapericardial wire, pleural perforation, phrenic nerve injury despite protective strategies, hemoperitoneum, and abdominal-pericardial fistula. Conclusion: Vigilance both during and after EpiAcc is needed to recognize these complications, some of which may be life-threatening. [Copyright &y& Elsevier]

Objectives: This study sought to assess the safety and effectiveness of a novel cryoballoon ablation technology designed to achieve single-delivery pulmonary vein (PV) isolation. Background: Standard radiofrequency ablation is effective in eliminating atrial fibrillation (AF) but requires multiple lesion delivery at the risk of significant complications. Methods: Patients with documented symptomatic paroxysmal AF and previously failed therapy with ≥1 membrane active antiarrhythmic drug underwent 2:1 randomization to either cryoballoon ablation (n = 163) or drug therapy (n = 82). A 90-day blanking period allowed for optimization of antiarrhythmic drug therapy and reablation if necessary. Effectiveness of the cryoablation procedure versus drug therapy was determined at 12 months. Results: Patients had highly symptomatic AF (78% paroxysmal, 22% early persistent) and experienced failure of at least one antiarrhythmic drug. Cryoablation produced acute isolation of three or more PVs in 98.2% and all four PVs in 97.6% of patients. PVs isolation was achieved with the balloon catheter alone in 83%. At 12 months, treatment success was 69.9% (114 of 163) of cryoblation patients compared with 7.3% of antiarrhythmic drug patients (absolute difference, 62.6% [p < 0.001]). Sixty-five (79%) drug-treated patients crossed over to cryoablation during 12 months of study follow-up due to recurrent, symptomatic AF, constituting drug treatment failure. There were 7 of the resulting 228 cryoablated patients (3.1%) with a >75% reduction in PV area during 12 months of follow-up. Twenty-nine of 259 procedures (11.2%) were associated with phrenic nerve palsy as determined by radiographic screening; 25 of these had resolved by 12 months. Cryoablation patients had significantly improved symptoms at 12 months. Conclusions: The STOP AF trial demonstrated that cryoballoon ablation is a safe and effective alternative to antiarrhythmic medication for the treatment of patients with symptomatic paroxysmal AF, for whom at least one antiarrhythmic drug has failed, with risks within accepted standards for ablation therapy. (A Clinical Study of the Arctic Front Cryoablation Balloon for the Treatment of Paroxysmal Atrial Fibrillation [Stop AF]; NCT00523978) [Copyright &y& Elsevier]

Rationale and Objectives: Patients with atrial fibrillation undergo structural remodeling resulting in increased pulmonary vein sizes. Studies have demonstrated that these changes are reversible following successful ablation therapy. To date, analyses of pulmonary vein structure have focused on measurements at the pulmonary vein ostia, and the full extent of reverse remodeling along the length of the pulmonary veins has not yet been fully characterized. Materials and Methods: An automated, three-dimensional method is proposed that quantifies pulmonary vein geometry starting at the ostia and extending several centimeters into the veins. A centerline is tracked along the length of the pulmonary vein, and orthogonal planes are computed along the curve. The method was validated against manual measurements on each of the four pulmonary veins for 10 subjects. The proposed methodology was used to analyze the pulmonary veins in 21 patients undergoing cardiac ablation therapy with preoperative and postoperative computed tomographic scans. Results: Validation results demonstrated that the automated measurements closely followed the manual measurements, with an overall mean difference of 11.50 mm2. Significant differences in cross-sectional area at the two time points were observed at all pulmonary vein ostia and extending for 2.0 cm (excluding the 0.5-cm interval) into the left inferior pulmonary vein, 3.5 cm into the left superior pulmonary vein, and 2.0 cm into the right superior pulmonary vein. Conclusions: Quantitative analysis along the length of the pulmonary veins can be accomplished using centerline tracking and measurements from orthogonal planes along the curve. The patient study demonstrated that reverse structural remodeling following ablation therapy occurs not only at the ostia but for several centimeters extending into the pulmonary veins. [ABSTRACT FROM AUTHOR]

Background: It is known that statins are effective in preventing atrial fibrillation (AF) in patients undergoing cardiac surgery. Objective: The purpose of this study was to evaluate the efficacy of statins in preventing AF recurrence following left atrial ablation. Methods: One hundred twenty-five patients who had no statin indication undergoing catheter ablation due to drug-refractory paroxysmal (n = 90) or persistent (n = 35) AF were randomized in a prospective, double-blind, placebo-controlled trial to receive 80 mg atorvastatin (n = 62) or placebo (n = 63) for 3 months. The primary endpoint was freedom from symptomatic AF at 3 months. Secondary endpoints included freedom from any atrial arrhythmia recurrence irrespective of symptoms, quality of life (QoL), and reduction in C-reactive protein (CRP). Results: At 3 months, 95% of patients in the atorvastatin group were free of symptomatic AF compared with 93.5% in the placebo group (P = .75). Similarly, 85% of patients treated in the atorvastatin group remained free of any recurrent atrial arrhythmia vs 88% of patients in the placebo group (P = .37). Mean CRP levels decreased in the atorvastatin group (mean change −0.75 ± 3, P = .02) and increased in the placebo group (mean change 2.1 ± 19.9, P = .48). Mean QoL score improved significantly in both groups (mean change 13.14 ± 18.2 in the atorvastatin group and 11.10 ± 17.7 in the placebo group, P = .53). Conclusion: In patients with no standard indication for statin therapy, treatment with atorvastatin 80 mg/day following AF ablation does not decrease the risk of AF recurrence in the first 3 months and should not be routinely administered to prevent periprocedural arrhythmias. [ABSTRACT FROM AUTHOR]

Background: Cardiac resynchronization therapy (CRT) is a therapy of proven benefit in patients with advanced heart failure. Identifying potential responders remains challenging, and whether the etiology of the heart failure is related to the potential hemodynamic benefit and long-term outcome of CRT is unclear. Objective: The purpose of this study was to evaluate whether heart failure etiology (ischemic cardiomyopathy [ICM] vs nonischemic dilated cardiomyopathy [DCM]) was associated with CRT outcome and implantable cardioverter-defibrillator (ICD) shocks. Methods: The study included 503 CRT recipients (CRT-D 90%) in a longitudinal CRT database: ICM (n = 312) and DCM (n = 191). Clinical variables and echocardiographic measures preimplant and postimplant were collected. Actuarial survival and ICD therapy data were assessed with Kaplan-Meier curve and log rank tests. Results: Pre-CRT, ICM patients were older and had higher creatinine levels (P <.001). At median follow-up of 7.1 months, the DCM group experienced greater improvement in left ventricular ejection fraction (8.3% ± 10% vs 6.2% ± 10%, P = .05) and left ventricular end-diastolic volumes than did those with ICM (−28%.4 ± 53 mL vs −15.3 ± 46 mL, P = .024). Survival estimates at 4 years were 55% for ICM and 77% for DCM groups (P <.001), respectively, whereas no significant difference in the incidence of appropriate/inappropriate ICD shocks was observed. The ICM group remained at higher risk for death compared to the DCM group after controlling for preimplant variables (hazard ratio 1.6, 95% confidence interval 1.1–2.3, P = .008). Conclusion: In response to CRT and in contrast to ICM, DCM patients experienced greater improvement in left ventricular systolic function and reverse remodeling while also sustaining a greater survival benefit. [ABSTRACT FROM AUTHOR]

Background: Cryoenergy is being increasingly used for atrial fibrillation (AF) ablation, but the thermal effect of cryoenergy on the esophagus remains undefined. Objective: This study examines the esophageal effects of cryoenergy used during AF ablation. Methods: Catheter ablation was performed using a cryoballoon catheter in 67 AF patients (Cryoballoon group), and a spot cryocatheter to complete irrigated radiofrequency lesion sets at segments in close proximity to the esophagus in 7 AF patients (Cryo-Focal group). A temperature probe monitored the luminal esophageal temperature (LET) in all patients; LET changes did not guide therapy. Post-procedural endoscopy was performed on 35 of 67 (52%) Cryoballoon and all Cryo-Focal patients. Results: Significant LET decreases (>1°C) occurred in 62 of 67 (93%) Cryoballoon patients. LET continued to decrease after termination of cryoablation before recovering to normal. Temperature decreases were more pronounced during ablation at the inferior (3.1°C) than superior pulmonary veins (1.5°C); the lowest observed temperature was 0°C. Post-procedural endoscopy showed esophageal ulcerations in 6 of 35 (17%) patients. There were no atrial-esophageal fistulas, and all ulcers had healed on follow-up endoscopy. Patients with and without ulceration differed with respect to mean LET nadir, cumulative LET decrease, and number of LETs <30°C. In the Cryo-Focal group, 6 ± 2 spot cryolesions per patient resulted in 1.3 ± 1 LET decreases per patient, and an absolute nadir of 32.5°C. Conclusion: Cryoballoon ablation can cause significant LET decreases, resulting in reversible esophageal ulcerations in 17% of patients. No ulcerations occurred with adjunctive spot cryoablation at regions near the esophagus during radiofrequency ablation procedures. [Copyright &y& Elsevier]