The cardiovascular benefits of physical activity are indisputable. Nevertheless, growing evidence suggests that both atrial fibrillation and right ventricular arrhythmia can be caused by intense ...exercise in some individuals. Exercise-induced atrial fibrillation is most commonly diagnosed in middle-aged, otherwise healthy men who have been engaged in endurance training for >10 years, and is mediated by atrial dilatation, parasympathetic enhancement, and possibly atrial fibrosis. Cardiac ablation is evolving as a first-line tool for athletes with exercise-induced arrhythmia who are eager to remain active. The relationship between physical activity and right ventricular arrhythmia is complex and involves genetic and physical factors that, in a few athletes, eventually lead to right ventricular dilatation, followed by subsequent myocardial fibrosis and lethal ventricular arrhythmias. Sinus bradycardia and atrioventricular conduction blocks are common in athletes, most of whom remain asymptomatic, although incomplete reversibility has been shown after exercise cessation. In this Review, we summarize the evidence supporting the existence of exercise-induced arrhythmias and discuss the specific considerations for the clinical management of these patients.
First-in-man studies of leadless pacemakers have demonstrated high rates of implant success, and safety and efficacy objectives were achieved. Outside of the investigational setting, there are ...concerns, particularly over cardiac effusion and perforation, device dislodgement, infection, telemetry, and battery issues.
The acute performance of the Micra transcatheter pacemaker from a worldwide Post-Approval Registry is reported.
The registry is an ongoing prospective single-arm observational study designed to assess the safety and effectiveness of Micra in the post-approval setting. The safety end point was system- or procedure-related major complications at 30 days post implant. We compared the major complication rate with that of the 726 patients from the investigational study. Electrical performance was also characterized.
The device was successfully implanted in 792 of 795 registry patients (99.6%) by 149 implanters at 96 centers in 20 countries. Through 30 days post implant, a total of 13 major complications occurred in 12 patients, for a major complication rate of 1.51% (95% confidence interval, 0.78%-2.62%). Major complications included cardiac effusion/perforation (1, 0.13%), device dislodgement (1, 0.13%), and sepsis (1, 0.13%). After adjusting for baseline differences, the rate of major complications in the registry trended lower than the investigational trial (odds ratio, 0.58, 95% confidence interval, 0.27-1.25; P = .16). Early pacing capture thresholds were low and stable.
Performance of the Micra transcatheter pacemaker in a real-world setting demonstrates a high rate (99.6%) of implant success and low rate (1.51%) of major complications through 30 days post implant. In particular, the rates of pericardial effusion, device dislodgement, and infection were low, reinforcing the positive results seen in the investigational study.
Catheter ablation (CA) is a highly effective therapy for the treatment of paroxysmal atrial fibrillation (AF) when compared with antiarrhythmic drug therapy (ADT). No randomized studies have compared ...the two strategies in persistent AF. The present randomized trial aimed to compare the effectiveness of CA vs. ADT in treating persistent AF.
Patients with persistent AF were randomly assigned to CA or ADT (excluding patients with long-standing persistent AF). Primary endpoint at 12-month follow-up was defined as any episode of AF or atrial flutter lasting >24 h that occurred after a 3-month blanking period. Secondary endpoints were any atrial tachyarrhythmia lasting >30 s, hospitalization, and electrical cardioversion. In total, 146 patients were included (aged 55 ± 9 years, 77% male). The ADT group received class Ic (43.8%) or class III drugs (56.3%). In an intention-to-treat analysis, 69 of 98 patients (70.4%) in the CA group and 21 of 48 patients (43.7%) in the ADT group were free of the primary endpoint (P = 0.002), implying an absolute risk difference of 26.6% (95% CI 10.0-43.3) in favour of CA. The proportion of patients free of any recurrence (>30 s) was higher in the CA group than in the ADT group (60.2 vs. 29.2%; P < 0.001) and cardioversion was less frequent (34.7 vs. 50%, respectively; P = 0.018).
Catheter ablation is superior to medical therapy for the maintenance of sinus rhythm in patients with persistent AF at 12-month follow-up.
NCT00863213 (http://clinicaltrials.gov/ct2/show/NCT00863213).
The role of high-intensity exercise and other emerging risk factors in lone atrial fibrillation (Ln-AF) epidemiology is still under debate. The aim of this study was to analyse the contribution of ...each of the emerging risk factors and the impact of physical activity dose in patients with Ln-AF.
Patients with Ln-AF and age- and sex-matched healthy controls were included in a 2:1 prospective case-control study. We obtained clinical and anthropometric data transthoracic echocardiography, lifetime physical activity questionnaire, 24-h ambulatory blood pressure monitoring, Berlin questionnaire score, and, in patients at high risk for obstructive sleep apnoea (OSA) syndrome, a polysomnography. A total of 115 cases and 57 controls were enrolled. Conditional logistic regression analysis associated height odds ratio (OR) 1.06 1.01-1.11, waist circumference (OR 1.06 1.02-1.11), OSA (OR 5.04 1.44-17.45), and 2000 or more hours of cumulative high-intensity endurance training to a higher AF risk. Our data indicated a U-shaped association between the extent of high-intensity training and AF risk. The risk of AF increased with an accumulated lifetime endurance sport activity ≥ 2,000 h compared with sedentary individuals (OR 3.88 1.55-9.73). Nevertheless, a history of <2000 h of high-intensity training protected against AF when compared with sedentary individuals (OR 0.38 0.12-0.98).
A history of ≥ 2,000 h of vigorous endurance training, tall stature, abdominal obesity, and OSA are frequently encountered as risk factors in patients with Ln-AF. Fewer than 2000 total hours of high-intensity endurance training associates with reduced Ln-AF risk.
Abstract
Aims
Our objectives were to compare effectiveness and long-term prognosis after epicardial thoracoscopic atrial fibrillation (AF) ablation vs. endocardial catheter ablation, in patients with ...prior failed catheter ablation or high risk of failure.
Methods and results
Patients were randomized to thoracoscopic or catheter ablation, consisting of pulmonary vein isolation with optional additional lines (2007–2010). Patients were reassessed in 2016/2017, and those without documented AF recurrence underwent 7-day ambulatory electrocardiography. The primary rhythm outcome was recurrence of any atrial arrhythmia lasting >30 s. The primary clinical endpoint was a composite of death, myocardial infarction, or cerebrovascular event, analysed with adjusted Cox proportional hazard ratios (HRs). One hundred and 24 patients were randomized with 34% persistent AF and mean age 56 years. Arrhythmia recurrence was common at mean follow-up of 7.0 years, but substantially lower with thoracoscopic ablation: 34/61 (56%) compared with 55/63 (87%) with catheter ablation adjusted HR 0.40, 95% confidence interval (CI) 0.25–0.64; P < 0.001. Additional ablation procedures were performed in 8 patients (13%) compared with 31 (49%), respectively (P < 0.001). Eleven patients (19%) were on anti-arrhythmic drugs at end of follow-up with thoracoscopy vs. 24 (39%) with catheter ablation (P = 0.012). There was no difference in the composite clinical outcome: 9 patients (15%) in the thoracoscopy arm vs. 10 patients (16%) with catheter ablation (HR 1.11, 95% CI 0.40–3.10; P = 0.84). Pacemaker implantation was required in 6 patients (10%) undergoing thoracoscopy and 3 (5%) in the catheter group (P = 0.27).
Conclusion
Thoracoscopic AF ablation demonstrated more consistent maintenance of sinus rhythm than catheter ablation, with similar long-term clinical event rates.
Abstract Objectives The aim of this study was to test the feasibility and usefulness of a new delayed-enhancement cardiac magnetic resonance (DE-CMR)–guided approach to ablate gaps in redo ...procedures. Background Recurrences of atrial fibrillation (AF) after pulmonary vein isolation (PVI) may be related to gaps at the ablation lines. DE-CMR allows identification of radiofrequency lesions and gaps (CMR gaps). Methods Fifteen patients undergoing repeated AF ablations were included (prior procedure was PVI in all patients and roof-line ablation in 8 patients). Pre-procedure 3-dimensional (3D) DE-CMR was performed with a respiratory-navigated (free-breathing) and electrocardiographically gated inversion-recovery gradient-echo sequence (voxel size 1.25 × 1.25 × 2.5 mm). Endocardium and epicardium were manually segmented to create a 3D reconstruction (DE-CMR model). A pixel signal intensity map was projected on the DE-CMR model and color-coded (thresholds 40 ± 5% and 60 ± 5% of maximum intensity). The DE-CMR model was imported into the navigation system to guide the ablation of CMR gaps, with the operator blinded to electrical data. Fifteen conventional procedures were used as controls to compare procedural duration, radiofrequency, and fluoroscopy times. Results Fifteen patients (56 pulmonary veins PVs; 57 ± 8 years of age; 9 with paroxysmal AF) were analyzed. In total, 67 CMR gaps were identified around PVs (mean 4.47 gaps/patient; median length 13.33 mm/gap) and 9 at roof line. All of the electrically reconnected PVs (87.5%) had CMR gaps. The site of electrical PV reconnection (assessed by circular mapping catheter) matched with a CMR gap in 79% of PVs. CMR-guided ablation led to reisolation of 95.6% of reconnected PVs (median radiofrequency time of 13.3 interquartile range: 7.5 to 21.7 min/patient) and conduction block through the roof line in all patients (1.4 interquartile range: 0.7 to 3.1 min/patient). Compared with controls, the CMR-guided approach shortened radiofrequency time (1,441 ± 915 s vs. 930 ± 662 s; p = 0.026) but not the procedural duration or fluoroscopy time. Conclusions DE-CMR can successfully guide repeated PVI procedures by accurately identifying and localizing gaps and may reduce procedural duration and radiofrequency application time.
Abstract
Aims
Edoxaban is a direct factor Xa inhibitor approved for stroke prevention in atrial fibrillation (AF). Uninterrupted edoxaban therapy in patients undergoing AF ablation has not been ...tested.
Methods and results
The ELIMINATE-AF trial, a multinational, multicentre, randomized, open-label, parallel-group study, was conducted to assess the safety and efficacy of once-daily edoxaban 60 mg (30 mg in patients indicated for dose reduction) vs. vitamin K antagonists (VKAs) in AF patients undergoing catheter ablation. Patients were randomized 2:1 to edoxaban vs. VKA. The primary endpoint (per-protocol population) was time to first occurrence of all-cause death, stroke, or International Society of Thrombosis and Haemostasis-defined major bleeding during the period from the end of the ablation procedure to end of treatment (90 days). Overall, 632 patients were enrolled, 614 randomized, and 553 received study drug and underwent ablation; 177 subjects underwent brain magnetic resonance imaging to assess silent cerebral infarcts. The primary endpoint (only major bleeds occurred) was observed in 0.3% (1 patient) on edoxaban and 2.0% (2 patients) on VKA hazard ratio (95% confidence interval): 0.16 (0.02–1.73). In the ablation population (modified intent-to-treat population including patients with ablation), the primary endpoint was observed in 2.7% of edoxaban (N = 10) and 1.7% of VKA patients (N = 3) between start of ablation and end of treatment. There were one ischaemic and one haemorrhagic stroke, both in patients on edoxaban. Cerebral microemboli were detected in 13.8% (16) patients who received edoxaban and 9.6% (5) patients in the VKA group (nominal P = 0.62).
Conclusion
Uninterrupted edoxaban therapy represents an alternative to uninterrupted VKA treatment in patients undergoing AF ablation.
Despite substantial technological and procedural advances that have improved the efficacy and safety of AF ablation in recent years, the long‐term durability of ablation lesions is still not ...satisfactory. There also remains concern regarding rare but potentially life‐threatening procedure‐related complications like cardiac tamponade and atrioesophageal fistulae. Current ablation strategies are aiming to optimize the trade‐off between efficacy and safety, where more extensive ablation appears to inevitably increase the risk of collateral injury. However, new forms of energy application may have the potential to resolve this quandary. The emerging concept of high power‐short duration radiofrequency ablation features a more favorable lesion geometry that appears ideally suited to create contiguous lesions in the thin‐walled atrium. Moreover, novel non‐thermal ablation methods based on electroporation appear to provide a unique selectivity for cardiomyocytes and to spare surrounding tissues composed of other cell types. Both, high power‐short duration and electroporation ablation might have the potential to break the trade‐off between effective lesions and collateral damage and to substantially improve risk‐benefit ratios in AF ablation. In addition, both approaches lead to considerable reductions in ablation times. However, their putative benefits regarding efficacy, efficiency, and safety remain to be proven in randomized controlled trials.
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