Strong linear relationship between heart rate and mean pulmonary artery pressure in exercising patients with severe precapillary pulmonary hypertension
Bibliographic record
Abstract
The contribution of heart rate (HR) to pulmonary artery hemodynamics has been suggested in pulmonary hypertension (PH). Our high-fidelity pressure, retrospective study tested the hypothesis that HR explained the majority of mean pulmonary artery pressure (mPAP) and pulse pressure (PApp) variation in 12 severe precapillary PH patients who performed incremental-load cycling while in the supine position. Seven idiopathic pulmonary arterial hypertension patients and five chronic thromboembolic PH patients were studied. Four to five PAP-thermodilution cardiac output (CO) points (mean: 4.4) were obtained. At rest, mPAP was 57 ± 9 mmHg, PApp was 51 ± 11 mmHg, HR was 90 ± 12 beats/min, and stroke volume (SV) was 50 ± 22 ml. At peak exercise, mPAP was 76 ± 10 mmHg, PApp was 67 ± 11 mmHg, and HR was 123 ± 18 beats/min (i.e., 71 ± 10% of maximum HR, each P < 0.05), whereas SV was 51 ± 20 ml (P = not significant). The input resistance did not change (mPAP/CO = 14.1 ± 4.1 vs. 13.5 ± 4.4 mmHg·min·l(-1)). The relative increase in mPAP was related to the relative increase in HR (n = 12, r(2) = 0.74) but not in CO. mPAP was linearly related to CO in 8 of 12 patients (median r(2) = 0.83) and to HR in 12 of 12 patients (median r(2) = 0.985). The parsimony principle favored the latter fit. PApp was linearly related to mPAP in 12 of 12 patients (median r(2) = 0.985), HR in 10 of 12 patients (median r(2) = 0.97), CO in 7 of 12 patients (median r(2) = 0.87), and SV in 1 of 12 patients. A strong linear relationship between HR and mPAP was consistently documented in severe precapillary PH patients who performed supine exercise. The limited value of thermodilution CO to predict mPAP could be explained by unavoidable precision errors in CO measurements, unchanged/decreased SV on exercise, curvilinearity of the mPAP-CO relationship at high flow, or flow-independent additional mechanisms increasing mPAP on exercise.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 | 0.001 |
| 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".