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Due to the still relatively high recurrence rate after atrial fibrillation (AF) ablation procedure, new tools and strategies to improve postablation freedom from AF are necessary. Recently, the new EnSite X EP cardiac mapping system has received the FDA authorization for its use. DiamondTemp™ is a new radiofrequency (RF) catheter commercialized by Medtronic company with accreditation for pulmonary veins isolation (PVI). The efficacy of this catheter in paroxysmal AF was confirmed by a recent publication (DIAMOND-AF). Currently, a new study is being carried out to validate the usefulness of this catheter in persistent AF: The DIAMOND-AF II. It seems interesting to describe and illustrate the combination of these two new technologies through a case report on persistent AF ablation. [ABSTRACT FROM AUTHOR]

Broadband satellite systems will need specific functions and interfaces in order to fit seamlessly into an end-to-end Next Generation Network (NGN) Quality of Service (QoS) architecture. This paper will define NGN overall architecture, showing how the coupling between Application/session layers and Network/transport layers can achieve end-to-end QoS support. Possible integration scenarios of satellite access into such architectures will be depicted, with a special emphasis on transparent and regenerative satellite architectures based on DVB-RCS [ETSI EN 301 790 v1.1.2 (2003)] type of access. Detailed architectures proposed by two recent research projects, IST Satellite Broadband Multimedia System for IPv6 (SATIP6) [http://satip6.tilab.com] and ESA Integrated Resources and QoS Management in DVB-RCS networks (QoSforRCS) [22nd AIAA Int. Communications Satellite Systems Conference; http://telecom.estec.esa.nl], will be presented. On the one hand, we will develop a “QoS assured” architecture proposed in the frame of QoSforRCS that provides dynamic Service Level Agreement (SLA) management and strict QoS control. The Admission Control (AC) function is located in the satellite Hub which allows fine control and billing by the Service Providers. On the other hand, a “QoS enabled” architecture proposed in the frame of SATIP6 is presented: it allows simple QoS differentiation between applications based on configuration by the end user or the subscriber's network administrator. This architecture may include AC function and is designed for Virtual Private Network (VPN) deployment. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 68-year-old female with symptomatic recurrent tachycardia. A transthoracic echocardiogram and a 12-lead electrocardiogram (ECG) showed no heart abnormalities. During an electrophysiological study, incessant irregular narrow QRS tachycardia was noted with intracardiac recording. The patient was treated with radiofrequency ablation without complications.

Cardiac resynchronization therapy (CRT) improves symptoms and survival in some selected heart failure patients. However, around 30% of patients still do not respond to CRT. In these patients, methodological approach of any potential cause of nonresponse should be reviewed. We describe the case of limited left ventricle (LV) myocardium capture by LV lead during biventricular pacing secondary to a slow conduction from LV lead impulse, located in a scar zone, and the benefit of interventricular delay optimization in this setting. This case emphasizes the interest of considering 12-lead electrocardiogram during management of patients with CRT. [ABSTRACT FROM AUTHOR]

Introduction: Multiple groups have reported on the usefulness of ablating in atrial regions exhibiting abnormal electrograms during atrial fibrillation (AF). Still, previous studies have suggested that ablation outcomes are highly operator‐ and center‐dependent. This study sought to evaluate a novel machine learning software algorithm named VX1 (Volta Medical), trained to adjudicate multipolar electrogram dispersion. Methods: This study was a prospective, multicentric, nonrandomized study conducted to assess the feasibility of generating VX1 dispersion maps. In 85 patients, 8 centers, and 17 operators, we compared the acute and long‐term outcomes after ablation in regions exhibiting dispersion between primary and satellite centers. We also compared outcomes to a control group in which dispersion‐guided ablation was performed visually by trained operators. Results: The study population included 29% of long‐standing persistent AF. AF termination occurred in 92% and 83% of the patients in primary and satellite centers, respectively, p = 0.31. The average rate of freedom from documented AF, with or without antiarrhythmic drugs (AADs), was 86% after a single procedure, and 89% after an average of 1.3 procedures per patient (p = 0.4). The rate of freedom from any documented atrial arrhythmia, with or without AADs, was 54% and 73% after a single or an average of 1.3 procedures per patient, respectively (p < 0.001). No statistically significant differences between outcomes of the primary versus satellite centers were observed for one (p = 0.8) or multiple procedures (p = 0.4), or between outcomes of the entire study population versus the control group (p > 0.2). Interestingly, intraprocedural AF termination and type of recurrent arrhythmia (i.e., AF vs. AT) appear to be predictors of the subsequent clinical course. Conclusion: VX1, an expertise‐based artificial intelligence software solution, allowed for robust center‐to‐center standardization of acute and long‐term ablation outcomes after electrogram‐based ablation. [ABSTRACT FROM AUTHOR]

Background: The assessment of noninvasive markers of left atrial (LA) low‐voltage substrate (LVS) enables the identification of atrial fibrillation (AF) patients at risk for arrhythmia recurrence after pulmonary vein isolation (PVI). Methods: In this prospective multicenter study, 292 consecutive AF patients (72% male, 62 ± 11 years, 65% persistent AF) underwent high‐density LA voltage mapping in sinus rhythm. LA‐LVS (<0.5 mV) was considered as significant at 2 cm2 or above. Preprocedural clinical electrocardiogram and echocardiographic data were assessed to identify predictors of LA‐LVS. The role of the identified LA‐LVS markers in predicting 1‐year arrhythmia freedom after PVI was assessed in 245 patients. Results: Significant LA‐LVS was identified in 123 (42%) patients. The amplified sinus P‐wave duration (APWD) best predicted LA‐LVS, with a 148‐ms value providing the best‐balanced sensitivity (0.81) and specificity (0.88). An APWD over 160 ms was associated with LA‐LVS in 96% of patients, whereas an APWD under 145 ms in 15%. Remaining gray zones improved their accuracy by introduction of systolic pulmonary artery pressure (sPAP) of 35 mmHg or above, age, and sex. According to COX regression, the risk of arrhythmia recurrence 12 months following PVI was twofold and threefold higher in patients with APWD 145–160 and over 160 ms, compared to APWD under 145 ms. Integration of pulmonary hypertension further improved the outcome prediction in the intermediate APWD group: Patients with APWD 145–160 ms and normal sPAP had similar outcome than patients with APWD under 145 ms (hazard ratio [HR] 1.62, p =.14), whereas high sPAP implied worse outcome (HR 2.56, p <.001). Conclusions: The APWD identifies LA‐LVS and risk for arrhythmia recurrence after PVI. Our prediction model becomes optimized by means of integration of the pulmonary artery pressure. [ABSTRACT FROM AUTHOR]

Background Atrial fibrillation (AF) progressively leads to electrical remodeling (ER) and anatomical-mechanical remodeling (AR), whose relationships in humans remain poorly known. Methods ER and AR were compared in patients undergoing percutaneous radiofrequency (RF) ablation for AF. ER was defined by right and left appendage activation rates as a surrogate for atrial refractory periods. AR was approached by left atrial (LA) diameters and area and left atrial appendage (LAA) area and contractile function (mean emptying flow velocity) (LAAFV) before RF ablation. Mean duration between successive LAA contractions was considered as LAA mechanical rate. Results Forty-one patients (31 men, age: 64 ± 9 years) with paroxysmal (27%), persistent (61%), or long-persistent AF (12%) were prospectively included (ejection fraction: 44 ± 16%). Parameters exploring AR were highly correlated to each other: LA area (28 ± 7 cm2), LAA area (5.7 ± 2.25 cm2), LA transverse (49 ± 7 mm), and anteroposterior diameter (59 ± 13 mm) or LAAFV (29 ± 13 cm/s; P < 0.05 for each comparison). Parameters exploring ER were also highly correlated: right atrial appendage (RAA; 181 ± 39 ms) and LAA (176 ± 33 ms) activation rates (P < 0.0001). There was no significant correlation between any ER and AR parameter. Only LAA mechanical rate (174 ± 36 ms) was correlated to LAA or RAA activations rates (P ≤ 0.01). Conclusion ER and AR are not mutually related, atrial activation rate being not correlated to LA or LAA size or function. Thus, the mechanisms leading to AF-induced atrial remodeling may differ for anatomical and electrophysiological aspects. [ABSTRACT FROM AUTHOR]

Background—Reperfusion during acute myocardial infarction remains the best treatment for reducing infarct size. Postconditioning, applied at the onset of reperfusion, reduces myocardial infarction both in animals and humans. The objective of this study was to identify the time delay to apply postconditioning at reperfusion, allowing preservation of cardioprotection in the mouse myocardium. This is a major issue in the management of acute myocardial infarction patients. Methods and Results-Mice were subjected to 40 minutes of ischemia and 60 minutes of reperfusion (IR60′). Postconditioning protocols corresponding to repetitive ischemia (3 cycles of 1 minute of ischemia and 1 minute of reperfusion) were applied during early reperfusion at various time durations (Δtt) after reopening of the coronary artery (Δt=10 seconds, 1, 5, 10, 15, 20, 30, and 45 minutes; PostCΔt). Infarct size/area at risk was reduced by 71% in PostCΔ1 compared with IR60′ mice (P=5×10-6). There was a linear correlation (r2=0.91) between infarct size and Δt, indicating that the cardioprotective effect of delayed postconditioning was progressively attenuated when Δt time increased. The protective effect of PostCΔ1 and PostCΔ15 was still effective when the duration of reperfusion was prolonged to 24 hours (IR24 hours; PostCΔ1 and PostCΔ15 versus IR24 hours, P=0.001). Similar results were obtained for internucleosomal DNA fragmentation and lactate dehydrogenase release. Conclusions-This study in our in vivo mouse model of myocardial IR shows for the first time that delaying the intervention of postconditioning to 30 minutes does not abrogate the cardioprotective effect of postconditioning. This finding provides evidence that the time window of protection afforded by postconditioning may be larger than initially reported. [ABSTRACT FROM AUTHOR]

A letter to the editor is submitted in response to the article "Predictive Value of Thromboembolic Risk Scores Before an Atrial Fibrillation Ablation Procedure" by M. Floria et al.