Impact of impaired myocardial deformations on exercise tolerance and prognosis in patients with asymptomatic aortic stenosis
Bibliographic record
Abstract
AIMS: As assessed by tissue Doppler velocities, longitudinal contraction is commonly altered at an earlier stage than radial contraction in patients with severe aortic stenosis (AS). However, its relationship to exercise tolerance or to prognosis has not been clearly established. By using two-dimensional (2D) echocardiographic strain, we sought to evaluate values of deformation components in the setting of severe AS and to correlate these values with exercise tolerance and with patients' outcome. METHODS AND RESULTS: Sixty-five asymptomatic patients with severe AS (aortic valve area <1 cm(2)) were studied by echocardiography and exercise treadmill and were compared with controls. Conventional echographic parameters as well as longitudinal, radial, and circumferential deformations by 2D strain were measured at rest. During exercise treadmill, maximum tolerated workload, maximum heart rate, blood pressure, and EKG ST variations were recorded. Patients were then followed during 12 months. Compared with controls, despite similar ejection fractions, AS patients presented with a significantly lower global longitudinal strain (GLS) (-17.8 +/- 3.5 vs. -21.1 +/- 1.8%, P < 0.05) more pronounced in the basal segments (BLS) (-12.4 +/- 2.9 vs. -18.4 +/- 2.5%, P < 0.05). No difference was observed in terms of radial or circumferential strains. In a subgroup of AS patients with abnormal response to exercise, GLS and BLS were significantly lower (-14.7 +/- 5.1 vs. -19.3 +/- 4.0% and -10.7 +/- 2.5 vs. -14.4 +/- 2.1%, P < 0.05). With cut-offs of -18 and -13%, GLS and BLS were able to determine an inadequate exercise response with a sensitivity and specificity of 68 and 75% (AUC 0.77), and 77 and 83% (AUC 0.81), respectively. Finally, patients with a basal strain below -13% presented with more cardiac events in the follow-up. CONCLUSION: In asymptomatic patients with severe AS, impaired longitudinal contraction assessed by 2D strain is associated with abnormal exercise response and with an increased risk of cardiac events during follow-up.
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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 | 0.000 |
| 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".