Exercise-induced QT/R-R-interval hysteresis as a predictor of myocardial ischemia

Abstract: Objectives: Exercise-induced QT/RR hysteresis exists when, for a given R-R interval, the QT interval duration is shorter during recovery after exercise than during exercise. We sought to assess the association between QT/RR hysteresis and imaging evidence of myocardial ischemia. Background: Because ischemia induces cellular disturbances known to decrease membrane action potential duration, we hypothesized a correlation between QT/RR and myocardial ischemia

Economic analysis of a transesophageal echocardiography-guided approach to cardioversion of patients with atrial fibrillation The ACUTE economic data at eight weeks

AbstractObjectivesThe aim of this study was to compare the relative cost of a transesophageal echocardiography (TEE)-guided strategy versus conventional strategy for patients with atrial fibrillation (AF) >2 days duration undergoing electrical cardioversion over an eight-week period.BackgroundThe Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) trial found no difference in embolic rates between the two approaches. However, the TEE-guided strategy had a shorter time to cardioversion and a lower rate of composite bleeding. While similar clinical efficacy was concluded, the relative cost of these two strategies has not been explored.MethodsTwo economic approaches were employed in the ACUTE trial. The first approach was based on hospital charge data from complete hospital Universal Billing Code of 1992 forms, a detailed hospital charge questionnaire, or imputation. Regression analysis was used to investigate the added cost of adverse events. The second economic approach involved the development of an independent analytic model simulating treatment and actual ACUTE outcome costs as a validation of clinically derived data. Sensitivity analysis was performed on the analytic model to investigate the potential range in cost differences between the strategies.ResultsA total of 833 of the 1,222 patients were enrolled from 53 U.S. sites; TEE-guided (n = 420) and conventional (n = 413). At eight-week follow-up, total mean costs did not significantly differ between the two groups, respectively ($6,508 vs.$6,239; difference of $269; p = 0.50). Cumulative costs were 24% higher in the conventional group, primarily due to increased incidence of bleeding and hospital costs associated with bleeding. A separate analytic model showed that treatment costs were higher for the TEE-guided strategy, but outcome costs were higher for the conventional strategy. Sensitivity analysis of the analytic model illustrated that varying the incidence and cost of major bleeding and the cost of TEE had the greatest impact on cost differences between the two groups.ConclusionsIn patients with AF >2 days duration undergoing electrical cardioversion, the TEE-guided group showed little difference in patient costs compared with the conventional group. The TEE strategy had higher initial treatment costs but lower outcome-associated costs. Cumulative costs were 24% higher in the conventional group, primarily due to bleeding. The TEE-guided strategy is an economically feasible approach compared with the conventional strategy

Selecting Strategies to Foster Economists\u27 Critical Thinking Skills: A Quantile Regression Approach

We consider three models of teaching strategies and their effect on developing economics graduates\u27 \u27analysis\u27, \u27deduction\u27 and \u27induction\u27 skills. For each model we compute quantile regression estimates for total sample, male, and female graduates separately. Results show that enriched lectures have a different effect on each critical thinking skill, while their effect differs for low, medium and high quantiles. Student-engaging strategies help more low-to-medium achievers. The third model is more explanatory, especially for low and high achievers. Male and female graduates respond differently to the use of each model. In conclusion, suggestions for strategy selection and further research are made

Worldwide Esophageal Cancer Collaboration : clinical staging data

Peer reviewe

A novel approach to cancer staging: application to esophageal cancer

A novel 3-step random forests methodology involving survival data (survival forests), ordinal data (multiclass forests), and continuous data (regression forests) is introduced for cancer staging. The methodology is illustrated for esophageal cancer using worldwide esophageal cancer collaboration data involving 4627 patients

Recommendations for neoadjuvant pathologic staging (ypTNM) of cancer of the esophagus and esophagogastric junction for the 8th edition AJCC/UICC staging manuals

We report analytic and consensus processes that produced recommendations for neoadjuvant pathologic stage groups (ypTNM) of esophageal and esophagogastric junction cancer for AJCC/UICC cancer staging manuals, 8(th) edition. The Worldwide Esophageal Cancer Collaboration (WECC) provided data for 22,654 patients with epithelial esophageal cancers; 7,773 had pathologic assessment after neoadjuvant therapy. Risk-adjusted survival for each patient was developed. Random Forest analysis identified data-driven neoadjuvant pathologic stage groups wherein survival decreased monotonically with increasing group, was distinctive between groups, and homogeneous within groups. An additional analysis produced data-driven anatomic neoadjuvant pathologic stage groups based only on ypT, ypN, and ypM categories. The AJCC Upper GI Task Force, by smoothing, simplifying, expanding, and assessing clinical applicability, produced consensus neoadjuvant pathologic stage groups. Grade and location were much less discriminating for stage grouping ypTNM than pTNM. Data-driven stage grouping without grade and location produced nearly identical groups for squamous cell carcinoma and adenocarcinoma. However, ypTNM groups and their associated survival differed from pTNM. The need for consensus process was minimal. The consensus groups, identical for both cell types were as follows: ypStage I comprised ypT0-2N0M0; ypStage II ypT3N0M0; ypStage IIIA ypT0-2N1M0; ypStage IIIB ypT3N1M0, ypT0-3N2, and ypT4aN0M0; ypStage IVA ypT4aN1-2, ypT4bN0-2, and ypTanyN3M0; and ypStage IVB ypTanyNanyM1. Absence of equivalent pathologic (pTNM) categories for the peculiar neoadjuvant pathologic categories ypTisN0-3M0 and ypT0N0-3M0, dissimilar stage group compositions, and markedly different early- and intermediate-stage survival necessitated a unified, unique set of stage grouping for patients of either cell type who receive neoadjuvant therapy