Left ventricular regional function and maximal exercise capacity in aortic stenosis
Bibliographic record
Abstract
AIMS: The objective assessment of maximal exercise capacity (MEC) using peak oxygen consumption (VO2) measurement may be helpful in the management of asymptomatic aortic stenosis (AS) patients. However, the relationship between left ventricular (LV) function and MEC has been relatively unexplored. We aimed to identify which echocardiographic parameters of LV systolic function can predict MEC in asymptomatic AS. METHODS AND RESULTS: Asymptomatic patients with moderate to severe AS (n = 44, aortic valve area <1.5 cm(2), 66 ± 13 years, 75% of men) and preserved LV ejection fraction (LVEF > 50%) were prospectively referred for resting echocardiography and cardiopulmonary exercise test. LV longitudinal strain (LS) of each myocardial segment was measured by speckle tracking echocardiography (STE) from the apical (aLS) 4-, 2-, and 3-chamber views. An average value of the LS of the analysable segments was provided for each myocardial region: basal (bLS), mid (mLS), and aLS. LV circumferential and radial strains were measured from short-axis views. Peak VO2 was 20.1 ± 5.8 mL/kg/min (median 20.7 mL/kg/min; range 7.2-32.3 mL/kg/min). According to the median of peak VO2, patients with reduced MEC were significantly older (P < 0.001) and more frequently females (P = 0.05). There were significant correlations between peak VO2 and age (r = -0.44), LV end-diastolic volume (r = 0.35), LV stroke volume (r = 0.37), indexed stroke volume (r = 0.32), and E/e' ratio (r = -0.37, all P < 0.04). Parameters of AS severity and LVEF did not correlate with peak VO2 (P = NS for all). Among LV deformation parameters, bLS and mLS were significantly associated with peakVO2 (r = 0.43, P = 0.005, and r = 0.32, P = 0.04, respectively). With multivariable analysis, female gender (β = 4.9; P = 0.008) and bLS (β = 0.50; P = 0.03) were the only independent determinants (r(2) = 0.423) of peak VO2. CONCLUSION: In asymptomatic AS, impaired LV myocardial longitudinal function determines reduced MEC. Basal LS was the only parameter of LV regional function independently associated with MEC.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| 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) | 0.000 | 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 teacher head, 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".