Differing sympathetic response during dynamic leg exercise in heart failure and age‐matched healthy subjects
Bibliographic record
Abstract
In human heart failure (HF), we showed that muscle sympathetic nerve activity (MSNA) increased during dynamic handgrip exercise at a lower threshold than age‐matched healthy controls. The aim of the present study was to compare the MSNA response during contra lateral leg cycling in HF and control subjects, hypothesizing that, in contrast to the drop in MSNA reported in controls, MSNA would increase in HF. We measured heart rate (HR), blood pressure (BP) and MSNA in the fibular nerve (microneurography) in 11 HF patients (left ventricular ejection fraction= 32±2%; age 61±3 years, (mean±SE)) and 8 healthy control subjects (55±2 years), during 2 minutes of upright one‐legged unloaded cycling followed by 2 minutes at 50% of peak oxygen uptake (VO2peak). Resting HR and BP were similar between groups but MSNA was significantly greater (84.3±3.7 vs 68.8±5.5 bursts/100 heart beats, P=0.02), and VO2peak lower (18.7±2.4 vs 32.7±4.3 ml•kg/min, P=0.008) in HF. HR was increased during exercise (P=0.002) with no group difference (P=0.25). As expected, MSNA burst frequency decreased during exercise in the healthy controls yet was increased in HF (−4.8±3.3 vs +5.1±2.8 bursts/min, P=0.028). The normal reduction in MSNA is offset in HF by one or more sympathoexcitatory responses that may represent greater activation of muscle mechanoreceptor, metaboreceptor or cardiac sympathetic reflexes. ( Heart and Stroke Foundation of Ontario)
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".