The utility of a novel mapping algorithm utilizing vectors and global pattern of propagation for scar-related atrial tachycardias.

BACKGROUND: Activation maps of scar-related atrial tachycardias (AT) can be challenging to interpret due to difficulty in inaccurate annotation of electrograms, and an arbitrarily predefined mapping window. A novel mapping software integrating vector data and applying an algorithmic solution taking into consideration global activation pattern has been recently described (Coherent™, Biosense Webster "Investigational"). OBJECTIVE: We aimed to assess the investigational algorithm to determine the mechanism of AT compared with the standard algorithm. METHODS: This study included patients who underwent ablation of scar-related AT using the Carto 3 and the standard activation algorithm. The mapping data were analyzed retrospectively using the investigational algorithm, and the mechanisms were evaluated by two independent electrophysiologists. RESULTS: A total of 77 scar-related AT activation maps were analyzed (89.6% left atrium, median tachycardia cycle length of 273 ms). Of those, 67 cases with a confirmed mechanism of arrhythmia were used to compare the activation software. The actual mechanism of the arrhythmia was more likely to be identified with the investigational algorithm (67.2% vs. 44.8%, p = .009). In five patients with dual-loop circuits, 3/5 (60%) were correctly identified by the investigational algorithm compared to 0/5 (0%) with the standard software. The reduced atrial voltage was prone to lead to less capable identification of mechanism (p for trend: .05). The investigational algorithm showed higher inter-reviewer agreement (Cohen's kappa .62 vs. .47). CONCLUSIONS: In patients with scar-related ATs, activation mapping algorithms integrating vector data and "best-fit" propagation solution may help in identifying the mechanism and the successful site of termination.

An oil spill surveillance program for Lake Pontchartrain.

This article describes an oil spill surveillance strategy implemented in response to BP's 2010 MC252 oil well blowout in the Gulf of Mexico. A three-pronged strategy consisted of Geographic Information System (GIS) monitoring of the surface slick, hydrodynamic modeling of the potential movement of the slick within the Basin, and weekly field reconnaissance. Our analysis was completed in near real time during the event and the results and predictions helped local responders minimize oiling impacts in Lake Pontchartrain. No prior planning was undertaken before this crisis response, and this article reports our support activities as they happened. For the GIS component, a remote sensing derived surface slick outline layer was obtained to produce near daily maps showing the slick's proximity to Lake Pontchartrain along with weather conditions and deployed response assets. This regular monitoring of the slicks' location was complemented by hydrodynamic numerical modeling that simulated the currents that determined the trajectories of oil particles. These data were ground-truthed through weekly reconnaissance trips that assessed the potential routes of oil penetration into Lake Pontchartrain for the presence of sheen, tarballs, and other oil constituents. Despite the ad hoc design and on-the-fly implementation, these three assessments provided consistent and actionable information.

Clinical and economic outcomes of liberal versus selective drug-eluting stent use: insights from temporal analysis of the multicenter Evaluation of Drug Eluting Stents and Ischemic Events (EVENT) registry.

BACKGROUND: Although the benefits of drug-eluting stents (DES) for reducing restenosis after percutaneous coronary intervention are well established, the impact of alternative rates of DES use on population-level outcomes is unknown. METHODS AND RESULTS: We used data from the Evaluation of Drug Eluting Stents and Ischemic Events (EVENT) registry to examine the clinical impact and cost-effectiveness of varying DES use rates in routine care. Between 2004 and 2007, 10,144 patients undergoing percutaneous coronary intervention were enrolled in the EVENT registry at 55 US centers. Clinical outcomes and cardiovascular-specific costs were assessed prospectively over 1 year of follow-up. Use of DES decreased from 92 in 2004 to 2006 (liberal use era; n=7587) to 68 in 2007 (selective use era; n=2557; P<0.001). One-year rates of death or myocardial infarction were similar in both eras. Over this time period, the incidence of target lesion revascularization increased from 4.1 to 5.1, an absolute increase of 1.0 (95 confidence interval, 0.1 to 1.9; P=0.03), whereas total cardiovascular costs per patient decreased by $401 (95 confidence interval, 131 to 671; P=0.004). The risk-adjusted incremental cost-effectiveness ratio for the liberal versus selective DES era was $16,000 per target lesion revascularization event avoided, $27,000 per repeat revascularization avoided, and $433 000 per quality-adjusted life-year gained. CONCLUSIONS: In this prospective registry, a temporal reduction in DES use was associated with a small increase in target lesion revascularization and a modest reduction in total cardiovascular costs. These findings suggest that although clinical outcomes are marginally better with unrestricted DES use, this approach represents a relatively inefficient use of healthcare resources relative to several common benchmarks for cost-effective care.