Impaired pulmonary oxygen uptake kinetics and reduced peak aerobic power during small muscle mass exercise in heart transplant recipients
Bibliographic record
Abstract
We examined peak and reserve cardiovascular function and skeletal muscle oxygenation during unilateral knee extension (ULKE) exercise in five heart transplant recipients (HTR, mean +/- SE; age: 53 +/- 3 years; years posttransplant: 6 +/- 4) and five age- and body mass-matched healthy controls (CON). Pulmonary oxygen uptake (Vo(2)(p)), heart rate (HR), stroke volume (SV), cardiac output (Q), and skeletal muscle deoxygenation (HHb) kinetics were assessed during moderate-intensity ULKE exercise. Peak exercise and reserve Vo(2)(p), Q, and systemic arterial-venous oxygen difference (a-vO(2diff)) were 23-52% lower (P < 0.05) in HTR. The reduced Q and a-vO(2diff) reserves were associated with lower HR and HHb reserves, respectively. The phase II Vo(2)(p) time delay was greater (HTR: 38 +/- 2 vs. CON: 25 +/- 1 s, P < 0.05), while time constants for phase II Vo(2)(p) (HTR: 54 +/- 8 vs. CON: 31 +/- 3 s), Q (HTR: 66 +/- 8 vs. CON: 28 +/- 4 s), and HHb (HTR: 27 +/- 5 vs. CON: 13 +/- 3 s) were significantly slower in HTR. The HR half-time was slower in HTR (113 +/- 21 s) vs. CON (21 +/- 2 s, P < 0.05); however, no significant difference was found between groups for SV kinetics (HTR: 39 +/- 8 s vs. CON 31 +/- 6 s). The lower peak Vo(2)(p) and prolonged Vo(2)(p) kinetics in HTR were secondary to impairments in both cardiovascular and skeletal muscle function that result in reduced oxygen delivery and utilization by the active muscles.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| 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".