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Introduction The efficacy of stereotactic body radiation therapy (SBRT) as an alternative treatment for recurrent ventricular tachycardia (VT) is still unclear. This study aimed to report the outcome of SBRT in VT patients with nonischemic cardiomyopathy (NICM). Methods The determination of the target substrate for radiation was based on the combination of CMR results and electroanatomical mapping merged with the real-time CT scan image. Radiation therapy was performed by Flattening-filter-free (Truebeam™) system, and afterward, patients were followed-up for 13.5±2.8 months. We analyzed the outcome of death, incidence of recurrent VT, ICD shocks, anti-tachycardia pacing (ATP) sequences, and possible irradiation side-effects. Results A total of 3 cases of NICM patients with anteroseptal scar detected by CMR. SBRT was successfully performed in all patients. During the follow-up, we found that VT recurrences occurred in all patients. In one patient, it happened during a 6-week blanking period, while the others happened afterward. Re-hospitalization due to VT only appeared in one patient. Through ICD interrogation, we found that all patients have reduced VT burden and ATP therapies. All of the patients died during the follow-up period. Radiotherapy-related adverse events did not occur in all patients. Conclusions SBRT therapy reduces the number of VT burden and ATP sequence therapy in NICM patients with VT, which had a failed previous catheter ablation. However, the efficacy and safety aspects, especially in NICM cases, remained unclear. This article is protected by copyright. All rights reserved.

Introduction A drug provocation test (DPT) is important for the diagnosis of Brugada syndrome (BrS). The link, however, between dynamic changes of ECG features after DPT and unstable ventricular arrhythmia (VA) in BrS remains unknown. Methods Between 2014 and 2019, we assessed 27 patients with BrS (median age: 37.0 [interquartile range, IQR: 22.0-51.0] years; 25 men], including 9 (33.3%) with a history of unstable VA and 18 (66.7%) without. All patients in the study presented with Brugada-like ECG features before DPT. The ECG parameters and dynamic changes (∆) in 12-lead ECGs recorded from the 2nd , 3rd , and 4th intercostal spaces (ICS) before and at 1, 6, 12, 18, 24 hours after DPT (oral flecainide 400 mg) were analyzed. Results The total amplitude of V1 at the 3rd ICS 18 and 24 hours after DPT was significantly lower in patients with history of unstable VA than in those without. Patients with BrS and unstable VAs had a significantly larger ∆ amplitude of V1 at the 2nd ICS 12 hours after DPT than in those without unstable VAs (0.28[0.18-0.41] mV vs. 0.08[0.01-0.15] mV, p=0.01). A multivariate analysis revealed that the amplitude of V1 at the 3rd ICS 18 and 24 hours after DPT and the ∆ amplitude of V1 at the 2nd ICS 12 hours after DPT were associated with history of unstable VA. Conclusion Nonuniform changes and spatiotemporal differences in precordial ECG features after DPT were observed in patients with BrS and these may be surrogate markers for risk stratification. This article is protected by copyright. All rights reserved.

INTRODUCTION Accurate identification of slow conducting regions in patients with scar-related atrial tachycardia (AT) is difficult using conventional electrogram annotation for cardiac electroanatomic mapping (EAM). Estimating delays between neighboring mapping sites is a potential option for activation map computation. We describe our initial experience with CARTO 3 Coherent Mapping (Biosense Webster Inc,) in the ablation of complex ATs. METHODS Twenty patients (58 ± 10 y/o, 15 males) with complex ATs were included. We created three-dimensional EAMs using CARTO 3 system with CONFIDENSE and a high-resolution mapping catheter (Biosense Webster Inc). Local activation time and coherent maps were used to aid in the identification of conduction isthmus (CI) and focal origin sites. System-defined slow or nonconducting zones and CI, defined by concealed entrainment (postpacing interval

Introduction We aimed to clarify the effect of vein of Marshall (VOM) ethanol infusion for treating VOM triggers and/or mitral flutter after first-attempt endocardial ablation in patients with nonparoxysmal atrial fibrillation (AF). Methods and results Of the 254 consecutive patients (age, 56 ± 10 years; 221 male) undergoing catheter ablation for drug-refractory nonparoxysmal AF, 32 (12.6%) received VOM ethanol infusion. The patients were stratified into group 1 (pulmonary vein isolation [PVI], substrate modification, VOM ethanol infusion), group 2 (PVI, substrate modification), and group 3 (PVI alone). Propensity-matched analysis (N = 128) of long-term outcomes (3.9 ± 0.5 years) revealed a higher AF recurrence risk in group 2 (hazard ratio [HR], 4.17; 95% confidence interval [95% CI], 1.63-10.69; P = .003) and group 3 (HR, 1.82; 95% CI, 1.09-3.04; P = .021) than in group 1, as well as a higher atrial arrhythmia recurrence risk in group 2 than in group 1 (HR, 2.42; 95% CI, 1.16-5.03; P = .018). A higher procedural termination rate was observed in group 1 than groups 2 and 3 (41.7% vs 17.2% vs 18.8%; P = .042). On multivariate analysis, VOM ethanol injection was an independent predictor of freedom from recurrence of AF (HR, 0.20; 95% CI, 0.08-0.52; P = .001) and atrial arrhythmia (HR, 0.35; 95% CI, 0.17-0.74; P = .005), whereas a left atrial diameter >45 mm and hypertension were independent risk factors for recurrence. Periprocedural complications rates were comparable among the groups. Conclusion Adjunctive VOM ethanol infusion is effective and safe for treating nonparoxysmal AF in patients with VOM triggers and/or refractory mitral flutter, providing good long-term freedom from AF and atrial arrhythmia.

INTRODUCTION Identifying the critical isthmus (CI) in scar-related macroreentrant atrial tachycardia (AT) is challenging, especially for patients with cardiac surgery. We aimed to investigate the electrophysiological characteristics of scar-related macroreentrant ATs in patients with and without cardiac surgery. METHODS A prospective study of 31 patients (mean age 59.4 ± 9.81 years old) with scar-related macroreentrant ATs were enrolled for investigation of substrate properties. Patients were categorized into the nonsurgery (n = 18) and surgery group (n = 13). The CIs were defined by concealed entrainment, conduction velocity less than 0.3 m/s, and the presence of local fractionated electrograms. RESULTS Among the 31 patients, a total of 65 reentrant circuits and 76 CIs were identified on the coherent map. The scar in the surgical group is larger than the nonsurgical group (18.81 ± 9.22 vs. 10.23 ± 5.34%, p = .016). The CIs in surgical group have longer CI length (15.27 ± 4.89 vs. 11.20 ± 2.96 mm, p = .004), slower conduction velocity (0.46 ± 0.19 vs. 0.69 ± 0.14 m/s, p

BACKGROUND: Epicardial adipose tissue is associated with coronary artery disease (CAD). Circulating endothelial progenitor cell (EPC) level represents a marker of endothelial dysfunction and vascular health. However, the relationship between epicardial fat and circulating EPC remains unknown. This study aimed to investigate association between echocardiographic epicardial fat thickness (EFT) and circulating EPC level. HYPOTHESIS: Epicardial fat causes inflammation and contributes to progression of CAD. METHODS: We enrolled 213 consecutive patients with stable angina, and EFT was determined by echocardiography. Quantification of EPC markers (defined as CD34 (+), CD34 (+) KDR (+), CD34 (+) KDR (+) CD133 (+) cells) in peripheral blood samples was used to measure circulating EPCs. All patients were divided into 3 tertiles according to EFT levels: group 1, low tertile of EFT; group 2, middle tertile of EFT; and group 3, high tertile of EFT. RESULTS: Among the 3 groups, CAD disease severity determined by SXscore was negatively correlated with EFT, but the difference did not reach statistical significance (P = 0.066). Additionally, patients in the high and middle tertiles of EFT had higher circulating EPC levels than did those in the low tertile of EFT (P = 0.001 and P < 0.001, respectively). In multivariate analysis, EPC level was significantly associated with echocardiographic EFT (standardized β = −0.233, P = 0.001), independent of multiple covariates. CONCLUSIONS: Epicardial adipose tissue is associated with circulating EPC levels. There was a trend between epicardial fat and severity of CAD, though analysis did not reach statistical significance, and this may be attributed to the interaction between several risk factors of CAD.

INTRODUCTION: Adjunctive driver-guided ablation in addition to pulmonary vein isolation has been proposed as a strategy to improve procedural success and outcomes for various populations with atrial fibrillation (AF). First, this study aimed to evaluate the different mapping techniques for driver/rotor identification and second to evaluate the benefits of driver/rotor-guided ablation in patients with paroxysmal and persistent AF (PerAF). METHODS: We searched the electronic database in PubMed using the keywords “atrial fibrillation,” “rotor,” “rotational driver,” “atrial fibrillation source,” and “drivers” for both randomized controlled trials and observational controlled trials. Clinical studies reporting efficacy or safety outcomes of driver-guided ablation for paroxysmal AF or (PerAF) were identified. We performed subgroup analyses comparing different driver mapping methods in patients with PerAF. The odds ratios (ORs) with random effects were analyzed. RESULTS: Out of 175 published articles, seven met the inclusion criteria, of which two were randomized controlled trials, one was quasiexperimental study, and four observational studies (three case-controlled studies and one cross-sectional study). Overall, adjunctive driver-guided ablation was associated with higher rates of acute AF termination (OR: 4.62, 95% confidence interval [CI]: 2.12–10.08; P < 0.001), lower recurrence of any atrial arrhythmia (OR: 0.44, 95% CI: 0.30–0.065; P < 0.001), and comparable complication incidence. CONCLUSIONS: Adjunctive driver-guided catheter ablation suggested an increased freedom from AF/AT relative to conventional strategies, irrespective of the mapping techniques. Furthermore, phase mapping appears to be superior to electrogram-based driver mapping in PerAF ablation.

Non-ischemic cardiomyopathies (NICMs) are composed of variable disease entities, including primary and secondary cardiomyopathies. Determining the etiology of NICM provides pivotal roles of not only the understanding of the individual pathogenesis, but also the clinical management, such as risk stratification, pharmacological treatment, and intervention therapies. Despite the diverse causes of NICM, these cases mostly require clinical attention owing to progressive myocardial injury, resulting in ventricular dysfunction and heart failure. The interaction between the diseased ventricular substrates and systemic/neurophysiological factors contributes to the cornerstones responsible for ventricular arrhythmogenesis and sudden cardiac death (SCD). Prevention of SCD and diminishing ventricular tachyarrhythmias are the important mainstays for the management of NICM patients. Given the understanding of the abnormal ventricular substrates and advancement of navigation systems, radiofrequency catheter ablation (RFCA) has become an adjunctive or alternative strategy for NICM patients who experience drug-refractory ventricular tachycardias (VTs). Successful ablation can frequently be achieved at the expense of an epicardial intervention. A recent study has proven the survival benefits for NICM patients who are free from recurrent VTs after a successful RFCA, regardless of the New York Heart Association (NYHA) functional class status or left ventricular ejection fraction. Additionally, recent evidence has highlighted the better delineation of a diseased myocardium through the incorporation of cardiovascular magnetic resonance imaging (CMRI) and 3-D mapping systems, which can facilitate the identification of critical ventricular arrhythmogenic substrates in NICM patients.