The distributed ASCI supercomputer project

The Distributed ASCI Supercomputer (DAS) is a homogeneous wide-area distributed system consisting of four cluster computers at different locations. DAS has been used for research on communication software, parallel languages and programming systems, schedulers, parallel applications, and distributed applications. The paper gives a preview of the most interesting research results obtained so far in the DAS project

Verification of pulmonary vein isolation during single transseptal cryoballoon ablation: a comparison between the classical circular mapping catheter and the inner lumen mapping catheter

Item does not contain fulltextAIMS: Cryoballoon ablation has proven very effective in achieving pulmonary vein isolation (PVI). The novel Achieve inner lumen mapping catheter designed to be used in conjunction with the cryoballoon, serves as both a guidewire and a mapping catheter. To our knowledge, this is the first study comparing the latter to verification of electrical isolation with the 'traditional' circular mapping catheter. METHODS AND RESULTS: We assigned 40 consecutive patients matched for age and left atrial diameter suffering of paroxysmal atrial fibrillation to cryoballoon PVI using either the circular mapping catheter or the Achieve as a mapping catheter. Duration of procedure as well as fluoroscopy times were significantly lower in the Achieve group than in the circular mapping catheter group (111 +/- 14 min vs. 126 +/- 13 min, P < 0.005 and 22 +/- 5 min vs. 29 +/- 4 min, P < 0.0001, respectively). There were no significant differences between both groups in terms of mean degree of occlusion, mean minimal temperatures, and PVI. Pulmonary vein isolation could be documented by real-time recordings in 55% of veins in the Achieve group with mean time to isolation of 65 +/- 23 s. CONCLUSION: Cryoballoon ablation in conjunction with the novel Achieve is feasible, safe, and affords PVI in nearly all veins in similar proportions to the approach with the traditional guidewire. Furthermore, if compared to the procedure with the circular mapping catheter, cryoballoon ablation with the Achieve is significantly faster and associated to shorter fluoroscopy times

Single procedural outcomes in the setting of percutaneous ablation for persistent atrial fibrillation: a propensity-matched score comparison between different strategies

BACKGROUND: Catheter ablation for persistent atrial fibrillation (persAF) is associated with less favorable outcomes than for paroxysmal AF. To improve success rates, left atrial (LA) substrate modification is frequently performed in addition to pulmonary vein isolation (PVI). The purpose of the study was to compare 4 different ablation approaches using radiofrequency catheter ablation (RFCA) or cryoballoon ablation (CB-A) for persAF and to evaluate the respective outcomes on a midterm follow-up of 12 months. METHODS: We did a propensity score-matched comparison of 30 patients undergoing PVI + LA posterior wall isolation (LAPWI) with CB-A, 30 patients who underwent PVI + linear ablation (roof and mitral lines) using RFCA, 60 patients with PVI alone using CB-A, and 60 patients who had PVI alone using RFCA. The endpoint was recurrence of documented atrial tachyarrhythmias (ATas) > 30 s at 1-year follow-up. RESULTS: After 12 months, freedom from ATas after a single procedure was 83.3% in the PVI + LAPWI group, 46.7% in the PVI + linear ablation group, 58.3% in the PVI-alone CB-A group, and 61.6% PVI-alone RFCA (p = 0.03). Moreover, freedom from ATas was significantly higher comparing the PVI + LAPWI group with each of the other groups. CONCLUSIONS: In this propensity-matched comparison of strategies for persAF, LAPW ablation in addition to PVI with CB-A seems to improve 1-year outcome in comparison to PVI + linear ablation using RFCA and to PVI alone using RFCA or CB-A. Randomized comparisons are eagerly awaited