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Several techniques are used for AF ablation, but no general consensus exists as to which technique is the most effective. At our center, we have developed a technique for isolating the pulmonary veins (PVs) at their antrum. The technique is guided by intracardiac echocardiography (ICE) and mapping with a circular (Lasso) catheter. Our technique was developed based on four crucial principles: 1. Precisely identifying the true border of the PV antrum. 2. Electrically isolating all of the PVs at the level of the antrum. 3. Avoiding risk of PV stenosis by ablating outside of the antrum. 4. Minimizing risk of other complications, such as perforation and stroke, by direct visualization during transseptal access and radiofrequency (RF) ablation.

The goal of this study was to assess the impact of left atrial scarring (LAS) on the outcome of patients undergoing pulmonary vein antrum isolation (PVAI) for atrial fibrillation (AF).Left atrial scarring may be responsible for both the perpetuation and genesis of AF.A total of 700 consecutive patients undergoing first-time PVAI were studied. Before ablation, extensive voltage mapping of the left atrium (LA) was performed using a multipolar Lasso catheter guided by intracardiac echocardiography (ICE). Patients with LAS were defined by a complete absence of electrographic recording by a circular mapping catheter in multiple LA locations, and this was validated by electroanatomic mapping. All four pulmonary vein antra and the superior vena cava were isolated using an ICE-guided technique. Patients were followed at least nine months for late AF recurrence. Univariate and multivariate analyses were performed to assess the predictive value of LAS and other variables on outcome.Of 700 patients, 42 had LAS, which represented 21 +/- 11% of the LA surface area by electroanatomic mapping. Patients with LAS had a significantly higher AF recurrence (57%) compared with non-LAS patients (19%, p = 0.003). Also, LAS was associated with a significantly larger LA size, lower ejection fraction, and higher C-reactive protein levels. Univariate analysis revealed age, nonparoxysmal AF, and LAS as predictors of recurrence. Multivariate analysis showed LAS as the only independent predictor of recurrence (hazard ratio 3.4, 95% confidence interval 1.3 to 9.4; p = 0.01).Pre-existent LAS in patients undergoing PVAI for AF is a powerful, independent predictor of procedural failure. Left atrial scarring is associated with a lower EF, larger LA size, and increased inflammatory markers.

Background— We describe the clinical and electrophysiological characteristics of a novel macroreentrant form of left atrial flutter circuit. Methods and Results— A total of 11 patients were included in the study. The mean tachycardia cycle length was 278±41 ms. Nine of the 11 patients were treated with antiarrhythmic drugs at the time of the study for concomitant atrial fibrillation. With the use of entrainment pacing and either the CARTO Biosense mapping system (9 patients) or conventional mapping (2 patients), the flutter circuit was found to rotate around the left septum primum with a critical isthmus located between the pulmonary veins posteriorly and/or mitral annulus anteriorly and the septum primum. In 5 patients, radiofrequency ablation was performed from the septum primum to the right inferior pulmonary vein (group 1), and in 6 patients, a lesion was made from the septum primum to the mitral annulus (group 2). After a follow-up of 13±6 months, 2 patients in group 1 and all patients in group 2 remained in sinus rhythm without recurrence. Conclusions— Slowing of electric conduction in the left atrial septum due to antiarrhythmic drugs and/or atrial myopathy seems to promote left septal atrial flutter. Radiofrequency ablation of this arrhythmia is usually effective and safe. A line of block between the septum primum and the mitral annulus proved to be effective for cure of tachycardia.

Objectives In patients with atrial flutter (AFL) and postoperative right atrial incisional scars, we sought to assess if the use of additional ablative lesions that targeted all potential re-entrant circuits, regardless of the presenting type of flutter, would prevent long-term recurrence. Background Patients with AFL and incisional scars have a complex atrial substrate that may promote multiple mechanisms of intra-atrial re-entry. Methods Twenty-nine patients with single right atrial incisional scars undergoing ablation for scar-dependent (n = 15) and cavotricuspid isthmus (CTI)-dependent (n = 14) flutter were studied. Results In the scar-dependent group, 9 of 15 (60%) patients had inducible or spontaneous CTI-dependent flutter immediately after ablation. In the group with CTI flutter, 7 of 14 (50%) patients had scar-related flutter immediately after ablation. If a second type of flutter was found during the initial ablation, a second ablation was performed either along the isthmus (scar-dependent group) or from the scar to another anatomic boundary (isthmus-dependent group). Patients were followed for 24 ± 5 months and 18 ± 6 months in the scar- and CTI-dependent groups, respectively. In the scar-dependent group, five of six (83%) who underwent only a single flutter line had recurrence at 3 ± 1 months. In the isthmus-dependent group, three of seven (42%) patients who had only one flutter line performed had recurrence at 5 ± 3 months. There was no flutter recurrence in patients who initially received two different flutter lines or in patients who subsequently underwent a second flutter line at follow-up. Conclusions In patients with postoperative right atrial incisional scar and flutter, multiple ablation lines that target both scar-related and classic isthmuses appear necessary to prevent long-term recurrence.

This document summarizes the technical progress from April to September 2003 for the program, Material and Process Development Leading to Economical High-Performance Thin-Film Solid Oxide Fuel Cells, contract number DE-AC26-00NT40711. Characteristics of doped lanthanum gallate (LSGMF) powder suitable for thin electrolyte fabrication have been defined. Bilayers with thin LSGMF electrolyte supported on an anode were fabricated and the fabrication process was improved. Preliminary performance was characterized. High performance cathode material Sr{sub 0.5}Sm{sub 0.5}CoO{sub 3} has been down-selected and is being optimized by modifying materials characteristics and processing parameters. The selected cathode exhibited excellent performance with cathode polarization of {approx}0.23 ohm-cm{sup 2} at 600 C.

Whilst atrial fibrillation (AF) is the commonest sustained arrhythmia worldwide, it is also the arrhythmia of the elderly with a lifetime AF risk >20% in the over 80s [1]. We are thus on the brink of an AF pandemic, not only due to our ever-aging population but also as a consequence of our population becoming increasingly obese and diabetic. In the US alone, it is expected that the current AF prevalence of ∼5 million will at least double by the middle of the century [1]. This represents a huge drain on healthcare resources, not only from the direct management of the arrhythmia but from the management of the associated increased rates of stroke, heart failure, and dementia.

Nanoporous materials with crystallographically defined pores represent an attractive class of materials for molecule discriminating chemical sensor applications. Recently, zeolite-modified surface acoustic wave (SAW), zeolite-loaded piezoelectric quartz crystal microgravimetric (QCM), and aluminophosphate molecular sieve coated capacitance devices have shown promise in selectively detecting organic molecules. As zeolites are electrical insulators it would be interesting to find electrically conducting open-framework materials whose charge-transport response is sensitive to the size and shape of adsorbed molecules. Recently, nanoporous tin(IV) sulfides have been synthesised and structurally characterized. Considering the semiconductor character of tin(IV) disulfide, the nanoporous tin(IV) sulfide versions are potentially interesting electronic molecular sieves for chemical sensing. In this paper synthetic, structural, ionexchange, thermochemical and vibrational information for various members of the R2Sn3S7 structure class of nanoporous tin(IV) sulfides, where R represents an alklyammonium template cation, will be briefly highlighted. The adsorption, optical and electrical responses of these materials are found to be sensitive to the identity and concentration of a range of molecular guests. Furthermore, their adsorption processes are fast and reversible. These are attributes of a molecule recognition material for sensing applications.

Should prophylactic amiodarone therapy be used to prevent atrial tachyarrhythmia after cardiac surgery?

The DISCERN AF study (Discerning Symptomatic and Asymptomatic Episodes Pre and Post Radiofrequency Ablation of Atrial Fibrillation) monitored atrial fibrillation (AF) using an implantable cardiac monitor (ICM) to assess the incidence and predictors of asymptomatic AF before and after catheter ablation.Patients with symptomatic AF underwent implantation of an ICM with an automated AF detection algorithm 3 months before and 18 months after ablation. Patients kept a standardized diary to record symptoms of arrhythmia, and ICM data were downloaded every 3 months. All episodes were blindly adjudicated and correlated with the diary. Asymptomatic recurrences were ICM episodes of 2 minutes or longer with no associated diary symptoms.Fifty patients had 2355 ICM episodes. Of these, 69.0% were true AF/atrial flutter (AFL)/atrial tachycardia (AT); 16.0%, sinus with extrasystoles; 11.0%, artifact; and 4.0%, sinus arrhythmia. Total AF/AFL/AT burden was reduced by 86% from a mean (SD) of 2.0 (0.5) h/d per patient before to 0.3 (0.2) h/d per patient after ablation (P.001), and 56.0% of all episodes were asymptomatic. The ratio of asymptomatic to symptomatic AF episodes increased after ablation from 1.1 to 3.7 (P = .002). By symptoms alone, 29 of 50 patients (58%) were free of AF/AFL/AT after ablation compared with 23 of 50 (46%) using ICM-detected AF/AFL/AT recurrence. Asymptomatic episodes were more likely AFL/AT and were significantly shorter and slower, with lower heart rate variability. However, the postablation state was the strongest independent predictor of asymptomatic AF.The ratio of asymptomatic to symptomatic AF episodes increased from 1.1 before to 3.7 after ablation. Postablation state is the strongest predictor of asymptomatic AF. Symptoms alone underestimate postablation AF burden, with 12% of patients having asymptomatic recurrences only.clinicaltrials.gov Identifier: NCT00745706.

The optimal ablation approach for patients with persistent atrial fibrillation (AF) remains unknown. In particular, it is unclear if pulmonary vein (PV) antral isolation (PVI) is sufficient as a lone strategy for persistent AF. Furthermore, if additional substrate ablation is to be added, the ideal approach to substrate ablation is yet to be determined.The aim of this study is to determine the optimal strategy of catheter ablation of persistent AF by comparing the efficacy of 3 strategies: PVI vs PVI plus complex fractionated electrogram (CFE) ablation (PVI + CFE) vs PVI plus linear ablation (PVI + Lines).The STAR AF II study (ClinicalTrials.gov NCT01203748) is a prospective, multicenter, randomized trial with a blinded assessment of outcomes. A total of 549 patients will be randomized in a 1:4:4 fashion to one of the investigation arms: PVI, PVI + CFE, and PVI + Lines, respectively. Patients undergoing a first-time ablation procedure for symptomatic, persistent AF that is refractory to at least 1 antiarrhythmic medication will be included. Persistent AF will be defined as a sustained episode lasting7 days and3 years. Patients with a left atrial parasternal size ≥60 mm will be excluded. The primary end point is freedom from documented AF30 seconds at 18 months after 1 or 2 ablation procedures with or without antiarrhythmic medications.The STAR AF II study is a randomized trial designed to evaluate the optimal approach for catheter ablation of persistent AF.

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Background— Left atrioesophageal fistula is a devastating complication of atrial fibrillation ablation. There is no standard approach for avoiding this complication, which is caused by thermal injury during ablation. The objectives of this study were to evaluate the course of the esophagus and the temperature within the esophagus during pulmonary vein antrum isolation (PVAI) and correlate these data with esophagus tissue damage. Methods and Results— Eight-one patients presenting for PVAI underwent esophagus evaluation that included temperature probe placement. Esophagus course was obtained with computed tomography, 3D imaging (NAVX), or intracardiac echocardiography. For each lesion, the power, catheter and esophagus temperature, location, and presence of microbubbles were recorded. Lesion location and esophagus course were defined with 6 predetermined left atrial anatomic segments. Endoscopy evaluated tissue changes during and after PVAI. Of 81 patients, the esophagus coursed near the right pulmonary veins in 23 (28.4%), left pulmonary veins in 31 (38.3%), and mid-posterior wall in 27 (33%). Esophagus temperature was significantly higher during left atrial lesions along its course than with lesions elsewhere (38.9±1.4°C, 36.8±0.5°C, P P Conclusions— Lesions near the course of the esophagus that generated microbubbles significantly increased esophagus temperature compared with lesions that did not. Power did not correlate with esophagus temperatures. Esophagus variability makes the avoidance of lesions along its course difficult. Rather than avoiding posterior lesions, emphasis could be placed on better esophagus monitoring for creation of safer lesions.

Background: Recurrence of atrial fibrillation (AF) occurs in up to 25% of patients after pulmonary vein antral isolation (PVAI). Recently, B-type natriuretic peptide (BNP) and C-reactive protein (CRP) have been associated with AF. We aimed to test the hypothesis that elevated preablation BNP or CRP levels can predict the recurrence of AF post-PVAI. Methods: BNP and CRP levels were prospectively drawn on all patients before ablation on the day of the scheduled procedure. Follow-up was performed by weekly transtelephonic transmissions, even if asymptomatic, for 3 months and scheduled Holter monitoring at follow-up. Uniand multivariate analyses were performed on demographic, clinical and echo data, CRP and BNP to determine predictors of AF recurrence. For regression analysis log BNP and log CRP were used because these values were skewed. Results: Between 3/03 and 1/04, 521 patients underwent PVAI. After 280 136 days of follow-up 20% of patients (102/521) had recurrence of AF, defined as recurrence after 8 weeks post PVAI. There was no difference in gender distribution (25% vs 30% females), hypertension, LV function (55.8 8% vs 55.6 6%), left ventricular hypertrophy (LVH), left atrial size, history of coronary artery disease (CAD), beta-blocker or pre-procedural antiarrhythmic drug use between the patients who developed recurrence of AF and those who did not. Pre-op plasma BNP and CRP levels were higher in the recurrence group (median 87pg/ml vs 58 pg/ml, Inter Quartile Range, IQR, [44,195] vs [25,114], p 0.005 for BNP and 2.6 mg/l vs 2.1mg/l, IQR [1.15,5.5] vs [1.02,4.4] for CRP). In regression analysis that included age, gender, hypertension, LV function, LVH, left atrial size, CAD, drug use, CRP and BNP levels, only BNP predicted recurrence of AF (Odds Ratio 3.2, 95% CI: 1.7-6.0, p 0.001). Conclusion: Pre-ablation plasma BNP level is an independent predictor of AF recurrence after PVAI. CRP levels were not predictive of recurrence. BNP may be a more sensitive marker of atrial remodeling than CRP, atrial size or LV function. AB8-3

The chemical diffusion and surface exchange coefficients were measured for SrFeO 3 - δ , La 0 . 5 Sr 0 . 5 FeO 3 - δ , and La 0 . 2 Sr 0 . 8 Cr 0 . 2 Fe 0 . 8 O 3 - δ at 790 ≤ T ≤ 1000°C and 0.01 ≤ pO 2 ≤ 1 atm by electrical conductivity relaxation. Values of the chemical diffusion (D c h e m ) and surface exchange (k c h e m ) coefficients were obtained by monitoring the variation of electrical conductivity after an abrupt change in oxygen partial pressure. The vacancy diffusion coefficient (D v ), oxygen ion self-diffusion coefficient (Do), and surface exchange coefficients at thermal equilibrium (k e x ) were calculated using the measured thermodynamic factors and were compared with literature data for other compositions.

Figure 1. A 52-year-old man with chronic left bundle-branch block presented with exertional syncope but no chest pain, palpitations, or dyspnea. His blood pressure was 95/60 mm Hg, and examination revealed signs of right ventricular failure and ascites. Transthoracic echocardiography revealed right ventricular dilatation and hypokinesis, with moderate tricuspid regurgitation and an estimated right ventricular systolic pressure of 55 mm Hg. Doppler studies of the legs showed bilateral proximal deep venous thrombosis, making the diagnosis of pulmonary embolism likely. Paracentesis and cytologic analysis of ascitic fluid revealed metastatic adenocarcinoma. Seven days after presentation, the patient had multiple episodes of arterial . . .