Single‐unit muscle sympathetic recordings identify in human heart failure unique fibers discharging in response to both unloading and loading of cardiopulmonary receptors (LB735)
Bibliographic record
Abstract
In healthy men, multi‐unit muscle sympathetic nerve activity (MSNA) has been shown to integrate two populations of single‐units exhibiting directionally opposite discharge to acute selective perturbations in atrial pressure. The behaviour of these single‐units was consistent during application of lower body negative and positive pressure (LBNP and LBPP). The aim of the present study was to compare single‐unit discharge characteristics of patients with and without heart failure (HF). We measured central venous pressure and single‐unit MSNA in 6 HF patients (LVEF: 24±6%; 54±13 years [mean±SD]) and 9 healthy controls (56±8 years) before and during 7 minutes of LBNP and LBPP (±10mmHg). These interventions had no effect on stroke volume, heart rate or systemic blood pressure (All P>0.05). Twelve HF and 22 control single‐units were identified. In controls, single‐unit responses to LBNP and LBPP exhibited either ‘anticipated’ (increased with LBNP and decreased with LBPP) or ‘paradoxical’ (decreased with LBNP and increased with LBPP) firing behavior. In HF, the majority (8/12; 67%) of single‐units exhibited a unique U‐shaped discharge pattern, with ‘anticipated’ responses to LBNP but ‘paradoxical’ responses to LBPP. This novel observation provides evidence for the emergence in HF of a population of cardiopulmonary mechanoreceptors exerting consistently sympathoexcitatory efferent firing characteristics. Grant Funding Source : Supported by the Canadian Institutes of Health Research (PJM) and Canadian Research Chairs program (JSF)
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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) | 0.002 | 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".