Ventricular-arterial coupling is preserved during exercise in patients with COPD
Bibliographic record
Abstract
COPD is associated with a higher risk of cardiac and vascular disease and an increased risk of cardiovascular (CV) mortality. However, it is unknown whether intrinsic changes to the heart, vasculature or the interaction between these two systems are altered in patients with COPD, especially when the CV system is placed under stress. As such, the aim of this study was to investigate whether ventricular-arterial coupling (arterial elastance [Ea]/end-systolic elastance [Ees]) is altered in COPD patients during exercise. Fifteen COPD patients and 14 healthy age, sex and activity matched controls underwent incremental exercise testing as well as echocardiography and blood pressure measurements at rest, 25, 50 and 75% workload maximum (Wmax). At rest and during exercise, there were no differences in Ea or Ees between groups. Subsequently, Ea/Ees was also similar decreasing from 0.84±0.22 to 0.53±0.18 between rest and 75%Wmax in COPD and 0.90±0.20 to 0.50±0.08 in controls. There was no association between VO2peak, Ea, Ees or Ea/Ees. However, there was a significant correlation between the change in Ea (ΔEa) from rest to 75%Wmax and the change in end diastolic volume (ΔEDV) in COPD patients (r=0.54, p<0.05) but not controls. These findings indicate that patients with COPD are able to reduce Ea/Ees during exercise demonstrating that they have adequate cardiovascular reserve capacity to deal with the increase in vascular load. However, the significant relationship between ΔEa and ΔEDV suggests that COPD patients who have large increases in arterial load during exercise fail to augment EDV, which would attenuate stroke volume and place a greater reliance on heart rate and Ees to increase cardiac output.
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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 | 0.001 |
| 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 | 0.001 | 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".