Inotropic Medication CausesShift in Exercise AnaerobicThreshold in Chronic HeartFailure Patients
Bibliographic record
Abstract
To determine if the gas exchange anaerobic threshold (GeAT) is altered by increases in cardiac function, 7 chronic heart failure (CHF) patients (age 56.4 ± 7.6 years) were studied by withdrawal and subsequent réintroduction of inotropic medication, digoxin, to evaluate the sensitivity and feasibility of utilizing GeAT during exercise testing as an additional marker of improved cardiac function. Treadmill tests using a modified Naughton treadmill protocol were done 1 week apart. Blood sampling was done prior to each exercise session to determine digoxin levels. Expired gases were collected using an automated metabolic measurement cart. GeAT was determined by examination of the plots of O(2) consumption (VO(2)) versus minute ventilation (V(E)), as well as end-tidal O(2) and CO(2). Dead space/tidal volume ratios (V(D)/V(T)) were calculated from expired gas variables at submaximal and peak exercise levels. Peak exercise rate pressure product increased from 18.7 to 22.7 bpm X mm Hg X 10^-3 on digoxin. VO(2) peak and relative GeAT (GeAT(rei)) were unchanged with digoxin (1.50 ± 0.58 to 1.60 ± 0.48 l ∙ min^-1, and from 70.3 ± 14.6 to 76.7 ± 11.3% of VO(2) peak, respectively). Absolute GeAT (GeAT(abs)) increased from 1.07 ± 0.39 to 1.23 ± 0.39 l ∙ min^-1 (p < 0.01) when on digoxin. No changes in V(D)/V(T) were observed at submaximal versus maximal exercise, nor with digoxin, suggesting that altered ventilation/perfusion imbalances were not related to the increased V(E) and GeAT during exercise under the off- or on-digoxin conditions. These data suggest that although VO(2) peak remains relatively unchanged with digoxin, the increase in GeAT(abs) (reflecting postponed skeletal muscle anaerobic metabolism) might constitute a more sensitive noninvasive marker of changes in blood flow and exercise capacity in CHF patients than VO(2) peak. Since peak systolic blood pressure increased on digoxin, GeAT might reflect increased myocardial function.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".