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Objectives This study aimed to assess the comparative efficacy of 4 ablation strategies on the incidence rates of freedom from atrial fibrillation (AF) or atrial tachycardia (AT) through a 3-year follow-up in patients with persistent AF. Background The optimal substrate modification strategies using catheter ablation for patients with persistent AF remain unclear. Methods Patients with persistent AF were enrolled consecutively to undergo each of 4 ablation strategies: (a) Group 1 (Gp 1, n=69), pulmonary vein isolation (PVI) plus rotor ablation assisted by similarity index and phase mapping; (b) Gp 2 (n=75), PVI plus linear ablations at the left atrium; (c) Gp 3 (n=42), PVI plus elimination of complex fractionated atrial electrograms; (d) Gp 4 (n=67), PVI only. Potential confounders were adjusted via a multivariate survival parametric model. Results Baseline characteristics were similar across the 4 groups. At a follow-up period of 34.9±38.6 months, patients in Gp 1 showed the highest rate of freedom from AF compared with the other 3 groups (p=0.002), while patients in Gp 3 and 4 showed lower rates of freedom from AT than those of the other two groups (p=0.006). Independent predictors of recurrence of AF were the ablation strategy (p=0.002) and left atrial diameter (LAD) (p=0.01). Conclusion In patients with persistent AF, a substrate modification strategy using rotor ablation assisted by similarity index and phase mapping provided a benefit for maintaining sinus rhythm compared to the other strategies. Both ablation strategy and baseline LAD predicted the 3-year outcomes of freedom from AT/AF This article is protected by copyright. All rights reserved.

Background Atrial fibrillation (AF) increases the risk of stroke and mortality. However, rhythm control strategy did not reduce cardiovascular risks in short-term studies. We hypothesize that rhythm control better prevents stroke and mortality than rate control in AF patients over a long-term period. Methods AF patients aged ≥18 years were identified from Taiwan National Insurance Database. Patients using anti-arrhythmia drugs to control rhythm at a >30 defined daily dose (DDD) were defined as the rhythm control group. Patients who used rate control medications for >30 DDDs constituted the rate control group. Multivariate Cox hazards regression model was used to evaluate the hazard ratio (HR) for major adverse cardiovascular events (MACE), including ischemic/hemorrhagic stroke and mortality. Results A total of 11,968 AF patients were enrolled, and 2850 of them (654 in rhythm control group; 2196 in rate control group) were analyzed. During a 6.3 ± 3.7 year's follow-up, a total of 1101 MACE occurred. Compared to rate control group, rhythm control group displayed a lower rate of ischemic stroke (adjusted HR: 0.65, p = 0.002) and mortality (adjusted HR: 0.81, p = 0.009). The rhythm control group showed a lower incidence of MACE than that of the rate control group (adjusted HR: 0.82, p = 0.009). The reduction of stroke (p = 0.004), mortality (p = 0.006), and MACE (p = 0.007) risk was observed particularly in rhythm control patients with a CHA2DS2-VASc score of ≥3. Conclusions In patients with AF, rhythm control better prevents MACE risk than rate control over a long-term period, particularly in those at high risk (CHA2DS2-VASc score ≥3) for stroke.

The data relates to the cohort of patients with atrial fibrillation (AF) from the National Health Insurance Research Database of Taiwan, "Rhythm Control Better Prevents Stroke and Mortality than Rate Control Strategies in Patients with Atrial Fibrillation - A Nationwide Cohort Study" (Weng et al., in press). The AF patients might receive either rate or rhythm control strategy according to the medication used. The baseline medication in rate and rhythm control groups was included in this dataset. Multivariate Cox hazards regression model was used to evaluate the hazard ratio (HR) for major adverse cardiovascular events (MACE), including ischemic/hemorrhagic stroke and mortality in AF patients receiving rate or rhythm control. The occurrence of MACE was identified from the ICD-9 CM codes. The data also contains the HR for MACE stratified by the CHA2DS2-VASc score, baseline characteristics, and the duration of strategy employed of the AF patients.

Objectives This prospective study compared the efficacy of atrial substrate modification guided by a nonlinear phase mapping technique with that of conventional substrate ablation. Background The optimal ablation strategy for persistent atrial fibrillation (AF) was unknown. Methods In phase 1 study, we applied a cellular automation technique to simulate the electrical wave propagation to improve the phase mapping algorithm, involving analysis of high-similarity electrogram regions. In addition, we defined rotors and focal AF sources, using the physical parameters of the divergence and curvature forces. In phase 2 study, we enrolled 68 patients with persistent AF undergoing substrate modification into 2 groups, group-1 (n = 34) underwent similarity index (SI) and phase mapping techniques; group-2 (n = 34) received complex fractionated atrial electrogram ablation with commercially available software. Group-1 received real-time waveform similarity measurements in which a phase mapping algorithm was applied to localize the sources. We evaluated the single-procedure freedom from AF. Results In group-1, we identified an average of 2.6 ± 0.89 SI regions per chamber. These regions involved rotors and focal sources in 65% and 77% of patients in group-1, respectively. Group-1 patients had shorter ablation procedure times, higher termination rates, and significant reduction in AF recurrence compared to group-2 and a trend toward benefit for all atrial arrhythmias. Multivariate analysis showed that substrate mapping using nonlinear similarity and phase mapping was the independent predictor of freedom from AF recurrence (hazard ratio: 0.26; 95% confidence interval: 0.09 to 0.74; p = 0.01). Conclusions Our study showed that for persistent AF ablation, a specified substrate modification guided by nonlinear phase mapping could eliminate localized re-entry and non-pulmonary focal sources after pulmonary vein isolation.

ObjectiveWe sought to assess whether genetic risk factors for atrial fibrillation (AF) can explain cardioembolic stroke risk.MethodsWe evaluated genetic correlations between a previous genetic study of AF and AF in the presence of cardioembolic stroke using genome-wide genotypes from the Stroke Genetics Network (N = 3,190 AF cases, 3,000 cardioembolic stroke cases, and 28,026 referents). We tested whether a previously validated AF polygenic risk score (PRS) associated with cardioembolic and other stroke subtypes after accounting for AF clinical risk factors.ResultsWe observed a strong correlation between previously reported genetic risk for AF, AF in the presence of stroke, and cardioembolic stroke (Pearson r = 0.77 and 0.76, respectively, across SNPs with p < 4.4 × 10−4 in the previous AF meta-analysis). An AF PRS, adjusted for clinical AF risk factors, was associated with cardioembolic stroke (odds ratio [OR] per SD = 1.40, p = 1.45 × 10−48), explaining ∼20% of the heritable component of cardioembolic stroke risk. The AF PRS was also associated with stroke of undetermined cause (OR per SD = 1.07, p = 0.004), but no other primary stroke subtypes (all p > 0.1).ConclusionsGenetic risk of AF is associated with cardioembolic stroke, independent of clinical risk factors. Studies are warranted to determine whether AF genetic risk can serve as a biomarker for strokes caused by AF.

Background Sepsis will induce stroke, new-onset atrial fibrillation (AF) increase ischemic stroke (IS) in in-hospitalization and long-term period after sepsis. Physicians must alert this condition and given suitable treatment. Aim The associated of IS and new-onset AF in septicemia survivors after discharge have to be evaluated. Design The inpatient data was used of the Taiwan National Health Insurance Database (NHIRD) in 2010. We identified patients suffered their first occurrence of septicemia (International Classification of Disease, Ninth Revision, Clinical Modification [ICD-9-CM] is 038, 003.1, 036.1) and excluded less than 18 years old. Patients had AF (ICD-9-CM to 427.3×) during the same admission or after septicemia hospitalization discharged were defined as new-onset AF. The outcome was IS happened after septicemia discharge (ICD-9-CM as 433-437). Methods The factors related to IS after septicemia survival were established using multivariate logistic regression with forward stepwise selection. Results There were 1286 new-onset AF and 1026 IS happened after septicemia discharge. The crude odds ratio (OR) were 3.88 (95% confidence interval [C.I.]: 1.69-8.89) and 1.62 (95% C.I.: 1.14-2.3) in middle-aged and elderly septicemia survivors with new-onset AF induced IS. The risk of IS after septicemia survivors was noticed adjusted OR 1.74 (95% C.I.: 1.26-2.41) for new-onset AF. Conclusion The middle-aged and elderly septicemia survivors suffered from new-onset AF had increased incidence of IS within three months. New-onset AF was a mediator factor of IS in septicemia survivors of Asian population.

Nonlinear Analysis of Atrial Fibrillation. Introduction: Currently, the identification of complex fractionated atrial electrograms (CFEs) in the substrate modification is mostly based on cycle length-derived algorithms. The characteristics of the fibrillation electrogram morphology and their consistency over time are not clear. The aim of this study was to optimize the detection algorithm of crucial CFEs by using nonlinear measure electrogram similarity. Methods and Results: One hundred persistent atrial fibrillation patients that underwent catheter ablation were included. In patients who required CFE ablation (79%), the time-domain fibrillation signals (6 seconds) were acquired for a linear analysis (mean fractionation interval and dominant frequency [DF]) and nonlinear-based waveform similarity analysis of the local electrograms, termed the similarity index (SI). Continuous CFEs were targeted with an endpoint of termination. Predictors of the various signal characteristics on the termination and clinical outcome were investigated. Procedural termination was observed in 39% and long-term sinus rhythm maintenance in 67% of the patients. The targeted CFEs didn't differ based on the linear analysis modalities between the patients who responded and did not respond to CFE ablation. In contrast, the average SI of the targeted CFEs was higher in termination patients, and they had a better outcome. Multivariate regression analysis showed that a higher SI independently predicted sites of termination (≥0.57; OR = 4.9; 95% CI = 1.33–18.0; P = 0.017). Conclusions: In persistent AF patients, a cycle length-based linear analysis could not differentiate culprit CFEs from bystanders. This study suggested that sites with a high level of fibrillation electrogram similarity at the CFE sites were important for AF maintenance. (J Cardiovasc Electrophysiol, Vol. 24, pp. 280-289, March 2013)

Background Atrial fibrillation (AF) causes atrial remodeling, and the left atrium (LA) is the favored substrate for maintaining AF. It remains unclear if AF remodels both atria differently and contributes to LA arrhythmogenesis and thrombogenesis. Therefore, we wished to characterize the transcript profiles in the LA and right atrium (RA) in sinus rhythm (SR) and AF respectively. Methods Paired LA and RA appendages acquired from patients receiving cardiac surgery were used for ion-channel- and whole-exome-based transcriptome analysis. The ultrastructure was evaluated by immunohistochemistry. Results Twenty-two and twenty ion-channels and transporters were differentially expressed between the LA and RA in AF and SR, respectively. Among these, 15 genes were differentially expressed in parallel between AF and SR. AF was associated with increased LA/RA expression ratio in 9 ion channel-related genes, including genes related to calcium handling. In microarray, AF was associated with a differential LA/RA gene expression ratio in 309 genes, and was involved in atherosclerosis-related signaling. AF was associated with the upregulation of thrombogenesis-related genes in the LA appendage, including P2Y12, CD 36 and ApoE. Immunohistochemistry showed higher expressions of collagen-1, oxidative stress and TGF-β1 in the RA compared to the LA. Conclusions AF was associated with differential LA-to-RA gene expression related to specific ion channels and pathways as well as upregulation of thrombogenesis-related genes in the LA appendage. Targeting the molecular mechanisms underlying the LA-to-RA difference and AF-related remodeling in the LA appendage may help provide new therapeutic options in treating AF and preventing thromboembolism in AF.

Herpes zoster (HZ) is associated with complications such as postherpetic neuralgia (PHN) and HZ ophthalmicus (HZO). However, few studies have focused on identifying patients having a high risk of PHN and HZO according to the initial presentation sites. The current study investigated these factors in a nationwide population-based cohort derived from Taiwan’s Longitudinal Health Insurance Database. The results indicate that the initial presentation sites can predict the complication site of HZ. In this study, elderly patients were found to be more susceptible to HZ and were the first to present with neurological signs (HZN). Furthermore, compared with patients with HZO and other signs (HZT), those with HZN had a higher comorbidity risk. Patients with HZN showed a significantly higher visceral complication risk than did those with HZO (adjusted hazard ratio [HR] = 1.47, 95% confidence interval [CI] = 1.27–1.71). In addition, patients with HZT showed lower risks of ocular and neurological complications than did those with HZN after stratification by age and sex (adjusted HR = 0.46, 95% CI = 0.31–0.68 and HR = 0.73, 95% CI = 0.59–0.91, respectively).

Background— Identification of critical atrial substrates in patients with nonparoxysmal atrial fibrillation (AF) failing to respond to pulmonary vein isolation is important. This study investigated the signal characteristics, substrate nature, and ablation results of rotors during AF. Methods and Results— In total, 53 patients (age=55±8), 31 with persistent AF and 22 with long-lasting AF, underwent pulmonary vein isolation and substrate modification of complex fractionated atrial electrograms. Small-radius-reentrant rotors were identified from signal analyses of the dominant frequency and fractionation interval and nonlinear analyses (newly developed, beat-to-beat nonlinear measurement of the repetitiveness of the electrogram morphology >6 seconds). In 15% of the patients, activation maps demonstrated occurrences of rotor-like small-radius reentrant circuits (n=9; 1.1 per patient; cycle length=110±21 ms; diameter=11±6 mm) with fibrillation occurring outside these areas. Rotors were identified by conventional point-by-point mapping and signal analyses and were subsequently eradicated by catheter ablation in these patients. Persistent AF for P P Conclusions— Rotor-like re-entry with fibrillatory conduction was found in a limited number of patients with nonparoxysmal AF after pulmonary vein isolation. Those areas were characterized by rapid repetitive activity with a high degree of electrogram similarity.

Background— The characteristics of atrial electrograms associated with atrial fibrillation (AF) termination are controversial. We investigated the electrogram characteristics that indicate procedural AF termination during continuous complex fractionated electrogram ablation. Methods and Results— Fifty-two consecutive patients with persistent AF (47 men; aged 54±9 years), who underwent electrogram-based catheter ablation in the left atrium and coronary sinus after pulmonary vein isolation, were enrolled. The intracardiac bipolar atrial electrogram recordings were characterized by (1) fractionation interval (FI) analysis (>6 seconds), (2) kurtosis (shape of the FI histogram), and (3) skewness (asymmetry of the FI histogram). Sites showing complex, fractionated electrograms (mean FI ≤60 ms) were targeted, and AF was terminated in 20 patients (38%) after the pulmonary vein isolation. The conventional complex fractionated electrogram sites (mean ≤120 ms) in patients with AF termination exhibited higher median kurtosis (2.69 [interquartile range, 2.03–3.46] versus 2.35 [interquartile range, 1.79–2.48]; P =0.024) and higher complex fractionated electrogram-mean interval (102.7±19.8 versus 87.7±15.0; P =0.008) than patients without AF termination. Furthermore, AF termination sites had higher median kurtosis than targeted sites without AF termination (5.13 [interquartile range, 3.51–6.47] versus 4.18 [interquartile range, 2.91–5.34]; P P =0.007). Conclusions— A kurtosis analysis using the FI histogram may be a useful tool in identifying the critical substrate for persistent AF and potential responders to catheter ablation.