Differential Response to Cardiac Resynchronization Therapy and Clinical Outcomes According to QRS Morphology and QRS Duration

ObjectivesThe goal of this study was to examine the relative impact of QRS morphology and duration in echocardiographic responses to cardiac resynchronization therapy (CRT) and clinical outcomes.BackgroundAt least one-third of all patients treated with CRT fail to derive benefit. Patients without left bundle branch block (LBBB) or patients with smaller QRS duration (QRSd) respond less or not at all to CRT.MethodsWe retrospectively assessed baseline characteristics, clinical and echocardiographic response, and outcomes of all patients who received CRT at our institution between December 2003 and July 2007. Patients were stratified into 4 groups according to their baseline QRS morphology and QRSd.ResultsA total of 496 patients were included in the study; 216 (43.5%) had LBBB and a QRSd ≥150 ms, 85 (17.1%) had LBBB and QRSd <150 ms, 92 (18.5%) had non-LBBB and a QRSd ≥150 ms, and 103 (20.8%) had non-LBBB and QRSd <150 ms. Echocardiographic response (change in ejection fraction) was better in patients with LBBB and QRSd ≥150 ms (12 ± 12%) than in those with LBBB and QRSd <150 ms (8 ± 10%), non-LBBB and QRSd ≥150 ms (5 ± 9%), and non-LBBB and QRSd <150 ms (3 ± 11%) (p < 0.0001). In a multivariate stepwise model with change in ejection fraction as the dependent variable, the presented classification was the most important independent variable (p = 0.0003). Long-term survival was better in LBBB patients with QRSd ≥150 ms (p = 0.02), but this difference was not significant after adjustment for other baseline characteristics (p = 0.15).ConclusionsQRS morphology is a more important baseline electrocardiographic determinant of CRT response than QRSd

Comparison of productivity of native and alien grass communities of South-Central Washington

Non

Natural vegetation at the proposed Reference Repository Location in southeastern Washington

The dominant shrubs were sagebrush and spiny hopsage; the herbs were dominated by cheatgrass and Sandberg bluegrass. Spiny hopsage appeared to be vulnerable to burning and also to damage by off-road vehicular traffic. It appears to have little or no ability to reproduce through seedlings; once the existing plants are killed they are not likely to be replaced, even if seed-producing plants are nearby. The only pure stand of spiny hopsage known to exist on the Hanford Site is on and near study plot 2H. Sagebrush, like spiny hopsage, is killed by burning and by heavy vehicles. Sagebrush is capable of reproducing via seeds, indicating that it is an inherently aggressive species with a capacity to reestablish itself if parent plants are in the vicinity to act as seed sources. Alien, annual plants, especially cheatgrass, were a major contributor to the herbaceous canopy cover in plots 3S, 4S, and 5S. However, native perennial grasses, especially Sandberg bluegrass, were a major contributor to the canopy cover in plots 1S and 2H. These differences are probably caused by differences in soil properties (e.g., water retention capacity), rather than to historical disturbances such as livestock grazing or wildfire. Specimens of Sandwort, Arenaria franklinii, growing near the Reference Repository Location were collected for examination by taxonomists to determine if the specimens are of the variety A. f. thompsonii, a taxon currently listed as threatened in the state of Washington. 16 refs., 7 figs., 3 tabs

Descriptions of plant communities at the proposed reference repository location and implications for reclamation of disturbed ground

This report presents an ecological description of the natural vegetation in the Cold Creek Valley located in the west central portion of the US Department of Energy's (DOE) Hanford Site in southeastern Washington state. The description includes plant species composition, canopy cover, and shrub density obtained from 10 study plots distributed in three habitat-types: sagebrush/Sandberg's bluegrass, spiny hopsage/Sandberg's bluegrass, and sagebrush/needle-and-thread grass. Of the relatively few species of shrubs and herbs in the Cold Creek Valley, the most abundant were sagebrush and spiny hopsage. The most abundant herbs were cheatgrass, Sandberg's bluegrass, and needle-and-thread grass. The amount of canopy cover provided by shrubs ranged between 7.4 and 33% in seven plots without a history of recent burning. Herbaceous plants in these same plots provided canopy cover that ranged between 18 and 41%. The three plots placed in areas with a recent history of burning had more herbaceous cover than did adjacent plots without a recent burn history. This was attributed to absence of living shrubs and freedom from competition for soil water and nutrients. There was less living herb cover in 1987 than in 1986 which is likely due to the lesser amount of growing season precipitation in 1987 (i.e. 10.3 cm vs 17.1 cm). Even with the absence of livestock grazing for 44 years, cheatgrass, an exotic annual generally provided more canopy cover than native perennial grasses. However, in the few places with good stands of Sandberg's bluegrass, cheatgrass was less abundant. 12 refs., 6 figs., 6 tabs

Vascular plants of waste storage sites in the 200 areas of the Hanford reservation

A brief accounting of terrestrial, riparian and semi-aquatic plants known to be associated with radioactive waste storage sites in the 200 Areas of the Hanford Reservation is given. In most cases the species are characteristic of those which generally inhabit the reservation, but some plants are restricted to specialized habitats provided by particular waste storage sites. It is impractical to list all species growing at each waste storage site because of seasonal variation and changes brought about by environmental management practices. An alpbabetical listing has been prepared with an example of where each species is known to occur. The list will be updated as needed and expanded to include other waste storage areas. Plant specimens were collected during spring and fall when flowering material was available. Herbarium mounts were prepared of many specimens and have been retained as part of the Hanford Reservation herbarium collection. Identification to species level was made whenever possible. Color photographs of the specimen mounts are used as training aids and demonstration material by ARHCO Radiation Monitoring personnel. (auth

Bird associations with shrubsteppe plant communities at the proposed reference repository location in southeastern Washington

This report provides information on te seasonal use of shrubsteppe vegetation by bird species at the RRL. Bird abundance and distribution were studied at the RRL to ensure that the DOE monitored migratory bird species pursuant to the Migratory Bird Treaty Act and to assess potential impacts of site characterization activities on bird populations. Birds were counted on two transects that together sampled an areas of 1.39 km/sup 2/. The relative abundance of birds, species richness, seasonal distribution, and the association of breeding shrubsteppe birds with major vegetation types were determined from Janurary through December 1987. Only 38 species were counted during 82 surveys. Total bird density during the nesting season (March-June) was 42.96 birdskm/sup 2/ and the density for the entire year was 26.74 birdskm/sup 2/. The characteristic nesting birds in shrubsteppe habitats were western meadowlark, sage sparrow, burrowing owl, mourning dove, horned lark, long-billed curlew, lark sparrow, and loggerhead shrike. Western meadowlark and sage sparrows were the most abundant breeding birds with an average density of 11.25 and 7.76 birdskm/sup 2/, respectively. Seasonal distribution of birds varied with species, but most species were present from March to September. Distribution and abunandance of nesting birds were correlated with habitat type. About 63% of the habitat surveyed was sagebrush, 26% was cheatgrass, and 11% was spiny hopsage. Sagebrush habitat supproted a greeater total bird density than cheatgrass or hopsage habitats. Sage sparrows were closely associated with sagebrush habitats, while western meadowlarks showed no strong habitat affinities. 22 refs., 9 figs., 6 tab

Radioecology of iodine-129: an interim report

Radioactive isotopes of iodine are Produced during nuclear fission in reactors and in weapons tests and to a limited extent in nature. Because of its extremely long half-life (1.6 x 10/sup 7/ yr) 1291 has the potential for accumulation in the environment from longterm, chronic releases from nuclear facilities. Possible problems associated with such an accumulation, including transfer of the /sup 129/I through the biosphere and resultant radiation doses to man and other organisms are discussed. (70 references) (CR