Physical Activity and Risk of Atrial Fibrillation: A Nationwide Cohort Study in General Population

Although exercise prevents cardiovascular disease and mortality, vigorous exercise and endurance athletics can cause atrial fibrillation (AF). However, no large cohort study has assessed the relationship between physical activity and AF in the general population. We assessed the effect of physical activity at different energy expenditures on the incidence of AF. We studied 501,690 individuals without pre-existing AF (mean age, 47.6 ± 14.3 years; 250,664 women [50.0%]) included in the Korean National Health Insurance Service database. The physical activity level was assessed using a standardized self-reported questionnaire at baseline. During a median follow-up of 4 years, 3,443 participants (1,432 women [41.6%]) developed AF. The overall incidence of AF at follow-up was 1.79 per 1,000 person-years. The subjects who met the recommended physical activity level (500-1,000 metabolic equivalent task [MET] minutes/week) had a 12% decreased AF risk (adjusted hazard ratio [HR]: 0.88, 95% confidence interval [CI]: 0.80-0.97), but not the insufficiently (1-500 MET-minutes/week; HR: 0.94, 95% CI: 0.86-1.03) and highly active subjects (≥1,000 MET-minutes/week; HR: 0.93, 95% CI: 0.85-1.03). The recommended minimum key target range of physical activity level was associated with the maximum benefit for reduced AF risk in the general population. The dose-response relationship between physical activity level and AF risk showed a U-shaped pattern. Although exceeding the key target range attenuated this benefit, it did not increase the AF risk beyond that during inactivity.ope

Effects of simvastatin on cardiac neural and electrophysiologic remodeling in rabbits with hypercholesterolemia

BACKGROUND: Significant cardiac neural and electrophysiologic remodeling occurs with hypercholesterolemia (HC). Whether simvastatin can reverse HC-induced remodeling is unclear. OBJECTIVE: The purpose of this study was to determine the mechanisms underlying the antiarrhythmic effects of statins. METHODS: Rabbits (N = 38) were fed HC chow (HC), standard chow (Control), HC chow followed by standard chow (Withdrawal), or HC chow and simvastatin (Statin) for 8 weeks. The hearts then were Langendorff-perfused for electrophysiologic studies. Nerves were identified by immunostaining of growth-associated protein-43 (GAP43) and tyrosine hydroxylase (TH). Action potential duration (APD) restitution in normal hearts with (N = 5) and without (N = 5) simvastatin therapy also was studied. RESULTS: Serum cholesterol levels (mg/dL) were 1,855 +/- 533 in HC, 50 +/- 21 in Control, 570 +/- 115 in Withdrawal, and 873 +/- 112 in Statin groups (P <.001). Compared with HC (16,700 +/- 5,342; 12,200 +/- 3,878 microm(2)/mm(2)), the Statin group had significantly reduced GAP43-positive (10,289 +/- 3,393 microm(2)/mm(2), P = .03) and TH-positive (7,685 +/- 2,959 microm(2)/mm(2), P = .04) nerve density, respectively. APD was longer in HC rabbits than in controls (192 +/- 20 ms vs 174 +/- 17 ms; P <.03). Withdrawal and Statin groups had less APD prolongation than HC group. Statin group has less repolarization heterogeneity than HC group (P <.01). Statin therapy flattened the slope of APD restitution in normal hearts. Ventricular fibrillation was either induced or occurred spontaneously in 79% of hearts in HC, 20% in Control, and 66% in Withdrawal groups. However, there was no VF in hearts of Statin group (P <.001). CONCLUSION: Simvastatin significantly reduced vulnerability to ventricular fibrillation via the mechanism of reduction of HC-induced neural and electrophysiologic remodelingope

Conduit Puncture for Electrophysiological Procedures in Patients with Fontan Circulation

Background: Electrophysiological procedures are challenging in patients who have undergone lateral tunnel or extracardiac conduit Fontan operation because the caval veins are not connected to the cardiac atria and ventricles. This study describes our experience in managing a series of patients with Fontan circulation requiring catheter ablation for arrhythmias. Methods: This study included eight consecutive patients with Fontan circulation who underwent catheter ablation or pacemaker implantation via Fontan conduit puncture [median age (interquartile range), 21.5 (16.0-25.8) years; 5 men]. Lateral tunnel and extracardiac conduit were equally distributed among the eight patients. A standard technique for conduit puncture and subsequent electrophysiologic procedure was used. The time taken for conduit puncture was compared for different types of conduits. Results: The median age of patients in this series was 21.5 years (interquartile range: 16.0-25.8 years). Fontan conduit puncture via right femoral vein under intracardiac echocardiographic guidance was successfully performed without complications in seven of the eight patients. Conduit puncture failed in one patient with extracardiac conduit made of the pericardium due to interruption of both femoral veins. In three patients with Fontan conduit made of pericardium, a Bronckenbrough transseptal needle or a radiofrequency transseptal needle with a snare was used. In four patients with Fontan conduit made of Gore-tex, a radiofrequency transseptal needle with a snare, and percutaneous transluminal angioplasty balloon were used. Fontan conduit puncture time was significantly longer in patients with conduit made of Gore-tex (median time, 91 min; interquartile range, 59.8-130.5 min) than in patients with conduit made of the pericardium (median time, 11.5 min; interquartile range, 10.0-18.3 min), respectively (p=0.020). Conclusions: Conduit puncture is feasible and safe in patients with lateral tunnel and extracardiac Fontan circulation. Puncture of the Gore-tex conduit is more difficult and time consuming than puncture of the pericardium conduit.ope

Prevalence and Characteristics of Atrial Tachycardia From Noncoronary Aortic Cusp During Atrial Fibrillation Catheter Ablation

Background and objectives: Atrial tachycardias (ATs) from noncoronary aortic cusp (NCC) uncovered after radiofrequency ablation for atrial fibrillation (AF) are rarely reported. This study was conducted to investigate the prevalence and clinical characteristics of NCC ATs detected during AF ablation and compare their characteristics with de novo NCC ATs without AF. Methods: Consecutive patients who underwent radiofrequency catheter ablation for AF were reviewed from the multicenter AF ablation registry of 11 tertiary hospitals. The clinical and electrophysiological characteristics of NCC AT newly detected during AF ablation were compared with its comparators (de novo NCC AT ablation cases without AF). Results: Among 10,178 AF cases, including 1,301 redo ablation cases, 8 (0.08%) NCC AT cases were discovered after pulmonary vein isolation (PVI; 0.07% in first ablation and 0.15% in redo ablation cases). All ATs were reproducibly inducible spontaneously or with programmed atrial stimulation without isoproterenol infusion. The P-wave morphological features of tachycardia were variable depending on the case, and most cases exhibited 1:1 atrioventricular conduction. AF recurrence rate after PVI and NCC AT successful ablation was 12.5% (1 of 8). Tachycardia cycle length was shorter than that of 17 de novo ATs from NCC (303 versus 378, p=0.012). No AV block occurred during and after successful AT ablation. Conclusions: Uncommon NCC ATs (0.08% in AF ablation cases) uncovered after PVI, showing different characteristics compared to de-novo NCC ATs, should be suspected irrespective of P-wave morphologies when AT shows broad propagation from the anterior interatrial septum.ope

Catheter Ablation of Atrial Fibrillation Raises the Plasma Level of NGF-β Which Is Associated with Sympathetic Nerve Activity

PURPOSE: The expression of nerve growth factor-β (NGF-β) is related to cardiac nerve sprouting and sympathetic hyper innervation. We investigated the changes of plasma levels of NGF-β and the relationship to follow-up heart rate variability (HRV) after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). MATERIALS AND METHODS: This study included 147 patients with AF (117 men, 55.8±11.5 years, 106 paroxysmal AF) who underwent RFCA. The plasma levels of NGF-β were quantified using double sandwich enzyme linked immunosorbent assay method before (NGF-β(pre)) and 1 hour after RFCA (NGF-β(post-1hr)). HRV at pre-procedure (HRV(pre)), 3 months (HRV(post-3mo)), and 1 year post-procedure (HRV(post-1yr)) were analyzed and compared with plasma levels of NGF-β. RESULTS: 1) The plasma levels of NGF-β significantly increased after RFCA (20.05±11.09 pg/mL vs. 29.60±19.43 pg/mL, p18 pg/mL, low frequency components (LF)/high-frequency components (HF) (p=0.003) and the number of atrial premature contractions (APCs, p=0.045) in HRV(post-3mo) were significantly higher than those with ≤18 pg/mL. 3) The LF/HF at HRV(post-3mo) was linearly associated with the NGF-β(pre) (B=4.240, 95% CI 1.114-7.336, p=0.008) and the NGF-β(post-1hr) (B=7.617, 95% CI 2.106-13.127, p=0.007). 4) Both NGF-β(pre) (OR=1.159, 95% CI 1.045-1.286, p=0.005) and NGF-β(post-1hr) (OR=1.098, 95% CI 1.030-1.170, p=0.004) were independent predictors for the increase of LF/HF at HRV(post-3mo). CONCLUSION: AF catheter ablation increases plasma level of NGF-β, and high plasma levels of NGF-β(pre) was associated with higher sympathetic nerve activity and higher frequency of APCs in HRV(post-3mo).ope

European Heart Rhythm Association (EHRA)/Heart Rhythm Society (HRS)/Asia Pacific Heart Rhythm Society (APHRS)/Latin American Heart Rhythm Society (LAHRS) expert consensus on risk assessment in cardiac arrhythmias: use the right tool for the right outcome, in the right population

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European Heart Rhythm Association (EHRA)/Heart Rhythm Society (HRS)/Asia Pacific Heart Rhythm Society (APHRS)/Latin American Heart Rhythm Society (LAHRS) expert consensus on risk assessment in cardiac arrhythmias: use the right tool for the right outcome, in the right population

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Electrophysiological Rotor Ablation in In-Silico Modeling of Atrial Fibrillation: Comparisons with Dominant Frequency, Shannon Entropy, and Phase Singularity.

BACKGROUND: Although rotors have been considered among the drivers of atrial fibrillation (AF), the rotor definition is inconsistent. We evaluated the nature of rotors in 2D and 3D in- silico models of persistent AF (PeAF) by analyzing phase singularity (PS), dominant frequency (DF), Shannon entropy (ShEn), and complex fractionated atrial electrogram cycle length (CFAE-CL) and their ablation. METHODS: Mother rotor was spatiotemporally defined as stationary reentries with a meandering tip remaining within half the wavelength and lasting longer than 5 s. We generated 2D- and 3D-maps of the PS, DF, ShEn, and CFAE-CL during AF. The spatial correlations and ablation outcomes targeting each parameter were analyzed. RESULTS: 1. In the 2D PeAF model, we observed a mother rotor that matched relatively well with DF (>9 Hz, 71.0%, p5.5 Hz, 39.7%, p<0.001), ShEn (upper 8.5%, 15.1%, p <0.001), and CFAE (lower 8.5%, 8.0%, p = 0.002). 3. In both the 2D and 3D models, virtual ablation targeting the upper 5% of the DF terminated AF within 20 s, but not the ablations based on long-lasting PS, high ShEn area, or lower CFAE-CL area. CONCLUSION: Mother rotors were observed in both 2D and 3D human AF models. Rotor locations were well represented by DF, and their virtual ablation altered wave dynamics and terminated AF.ope

Efficacy and safety of dronedarone versus placebo in patients with atrial fibrillation stratified according to renal function: Post hoc analyses of the EURIDIS-ADONIS trials

Background: The use of antiarrhythmic drugs (AADs) in patients with chronic kidney disease (CKD) is complex because impaired renal clearance can cause increased drug levels, and risk of intolerance or adverse events. Due to the propensity for CKD to occur alongside atrial fibrillation/atrial flutter (AF/AFL), it is essential that AAD safety and efficacy are assessed for patients with CKD. Hypothesis: Dronedarone, an approved AAD, may present a suitable therapeutic option for patients with AF/AFL and concomitant CKD. Methods: EURIDIS-ADONIS (EURIDIS, NCT00259428; ADONIS, NCT00259376) were identically designed, multicenter, double-blind, parallel-group trials investigating AF/AFL control with dronedarone 400 mg twice daily versus placebo (randomized 2:1). In this post hoc analysis, the primary endpoint was time to first AF/AFL. Patients were stratified according to renal function using the CKD-Epidemiology Collaboration equation and divided into estimated glomerular filtration rate (eGFR) subgroups of 30-44, 45-59, 60-89, and ≥90 ml/min. Time-to-events between treatment groups were compared using log-rank testing and Cox regression. Results: At baseline, most (86%) patients demonstrated a mild or mild-to-moderate eGFR decrease. Median time to first AF/AFL recurrence was significantly longer with dronedarone versus placebo for all eGFR subgroups except the 30 to 44 ml/min group, where the trend was similar but statistical power may have been limited by the small population. eGFR stratification had no significant effect on serious adverse events, deaths, or treatment discontinuations. Conclusions: This analysis suggests that dronedarone could be an effective therapeutic option for AF with an acceptable safety profile in patients with impaired renal function.ope

Coexisting sustained tachyarrthymia in patients with atrial fibrillation undergoing catheter ablation

BACKGROUND AND OBJECTIVES: During the index procedure of catheter ablation (CA) for atrial fibrillation (AF), it is important to assess whether other atrial or ventricular tachyarrhythmia coexist. Their symptoms are often attributed to residual tachycardia after successful elimination of AF by CA. This tachycardia could also be non-pulmonary vein (PV) foci initiated AF. This study examined the coexistence of other sustained tachyarrhythmia of patients who underwent radiofrequency CA (RFCA) for AF. SUBJECTS AND METHODS: Four hundred fifty-nine consecutive patients (375 males, aged 53.4+/-11.4 years) who underwent RFCA for AF were investigated. Atrial and ventricular programmed stimulation (PS) with or without isoproterenol infusion were performed, and spontaneously developed tachycardias were analyzed. RESULTS: Fifteen patients (3.3% of total) were diagnosed to have other sustained arrhythmias that included slow-fast type atrioventricular nodal reentrant tachycardia (AVNRT, n=6), atrioventricular reentrant tachycardia (AVRT, n=5) that utilized left posteroseptal (n=4) and parahisian bypass tract (n=1), atrial tachycardia (AT, n=2) originating from the foramen ovale (n=1) and the ostium of coronary sinus (n=1), sustained ventricular tachycardia (VT, n=2) involving one from the apical posterolateral wall of left ventricule in a normal heart and one from an anterolateral wall in an underlying myocardial infarction (MI). These sustained tachycardias were neither clinically documented nor had structural heart diseases, with the exception of one patient with MI associated VT. Two patients had the triple tachycardia; one involved AVNRT, AVRT, and AF, and the other involved VT, AT, and AF. All associated tachycardias were successfully eliminated by RFCA. CONCLUSION: Fifteen (3.3%) patients with AF had coexisting sustained tachycardia. RFCA was successful in these patients. Identification of tachycardia by PS before RFCA for AF should be done to maximize the efficacy of the first ablation session.ope