Analysis of prognostic significance of @entity943 after XXXX . Shortcomings of Lown grading system.

@entity1 @entity1165 @entity1540 @entity299 @entity583 @entity943 @entity204
The Lown grading system for @entity943 has been used in observational and experimental studies of @entity299 . This grading system uses three levels of @entity1540 frequency and four complex features to assign @entity1 to one of seven grades. We tested several of the major assumptions of the Lown grading system in a group of 400 @entity1 who had recently experienced acute @entity583 . The Lown grading system assumes that the frequency of @entity1540 exerts a negligible risk force in @entity1 who have complex @entity1540 . We found, however, that the frequency of @entity1540 contributed significant additional risk for @entity204 even in the three highest Lown grades, 4A, 4B, and 5. The Lown grading system assumes that, of the four complex features used, R on T @entity1540 have the greatest risk for subsequent @entity204 . We found that paired @entity1540 and @entity1165 had more prognostic significance than R on T @entity1540 . It is important for prognostic stratification that subgroups which are merged into a given Lown grade should be relatively homogeneous with respect to outcome. We found a lack of homogeneity in the three highest Lown grades. Grade 5 contained 16 subgroups with a mortality risk which ranged from 0 to 75 per cent; statistically significant differences in subsequent mortality were found among these subgroups. Most of the shortcomings of the Lown grading system in our acute @entity583 population resulted from failure to give sufficient weight to @entity1540 and to repetitive @entity1540 .
