O2pulse Trajectory As An Indicator Of Cardiorespiratory Fitness In Adults With Congenital Heart Disease
Bibliographic record
Abstract
Peak oxygen pulse (O2pulse) obtained with cardiopulmonary exercise testing (CPET) is defined as the ratio of oxygen uptake to heart rate (HR) at peak exercise. A surrogate for exercise stroke volume and arteriovenous O2 difference, O2pulse has prognostic value in adults with congenital heart disease (ACHD), but less is known about the significance of the O2pulse trajectory, an analysis of its kinetic response during CPET. PURPOSE: Determine significance and correlates of abnormal O2pulse trajectory in ACHD. METHODS: A retrospective analysis of ACHD patients who underwent CPET (including pre-exercise spirometry) and cardiac magnetic resonance (CMR) within ≤1-year apart as part of clinical evaluation at an ACHD specialty center. The O2pulse trajectory was defined as normal (normal curvilinear pattern) or abnormal (flat or decreasing trajectory) throughout the entire exercise period by visual assessment of a CPET expert. The results are reported as mean [SD] or number (%). Group differences (normal vs. abnormal O2pulse trajectory) were evaluated with independent samples T-tests for continuous variables or chi-square tests for nominal variables. RESULTS: CPET data of N = 217 ACHD patients included the following characteristics: 57% female, 75% white race, 36.2 [12.2] years of age, and body mass index (BMI; 28.4 [6.9] kg/m2). Within this group, a cohort of 132 patients (61%) had CMR within 1-year. 46% had abnormal O2pulse trajectory with Tetralogy of Fallot (n = 42 [19] %) being the most common lesion type. The CPET parameters of VO2peak (24.1 [9.9] vs. 20.5 [5.7] mL·kg-1·min-1) and peak O2pulse (13.1 [4.1] vs. 10.5 [3.0] mL/beat) were significantly lower in the abnormal O2pulse trajectory cohort with P < 0.001. Pre-exercise spirometry results of FVC-% and FEV1-% were lower in abnormal O2pulse trajectory cohort; P = 0.012, P = 0.010 respectively. Similarly, LV cardiac output (LVCO; P = 0.015), LV and RV ejection fraction (LVEF; P = 0.017 and RVEF; P < 0.001) were significantly lower. Age, sex, race, lesion type, BMI, hemoglobin levels, O2 saturations (SpO2), or use of beta-blocker was not different between groups (all P > 0.05). CONCLUSIONS: An abnormal O2pulse trajectory in ACHD is associated with lower cardiorespiratory fitness and reduced cardiac function and may have clinical significance in CPET interpretation. Dr. Canada is supported by a K23HL159270 grant from the National Heart, Lung, and Blood Institute.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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".