A comparison of Doppler, tissue Doppler imaging, and strain rate imaging in the assessment of postexercise left ventricular function
Bibliographic record
Abstract
Left ventricular (LV) function is characterized by contraction in the longitudinal, radial, and circumferential planes. Previous studies of postexercise changes in LV function have assessed global indices of LV function. The purpose of this study was to use 2-dimensional (2D) strain analysis to examine LV function following marathon running in the circumferential, radial, and longitudinal planes, and to compare these data with other global and regional indices of function. Fifteen (mean +/- SD: age, 32 +/- 7 years; stature, 1.76 +/- 0.08 m; body mass, 77.8 +/- 8.2 kg) competitors in the London Marathon were echocardiographically assessed pre- and postrace. 2D strain (ejection fraction (EF), Doppler (early (E) and late (A) trans-mitral filling), tissue Doppler imaging (TDI) (systolic (S') and early diastolic (E') wall-motion velocities); TDI-derived longitudinal strain (epsilon(TDI)), and systolic and diastolic strain rate (SR(TDI)); and 2D-derived peak circumferential, radial, and longitudinal strain (epsilon(2D)), and systolic and diastolic strain rate (SR(2D)) were examined. Differences pre- and postrace completion were assessed using paired tau tests, with alpha set at 0.01. All participants completed the marathon in a mean time of 213 +/- 41 min. A varied response was observed for measures of LV systolic and diastolic function following completion of the marathon (mean +/- SD): EF, 63 +/- 6 vs. 63 +/- 7% (p > 0.01); E:A, 1.70 +/- 0.37 vs. 1.17 +/- 0.37; E':A', 2.36 +/- 0.79 vs. 1.60 +/- 0.57 (p < 0.01); mean longitudinal epsilon(TDI), 19.1 +/- 5.1 vs. 17.5 +/- 4.2% (p < 0.01); mean longitudinal diastolic SR(TDI), 1.81 +/- 0.54 vs. 1.58 +/- 0.51 x s(-1) (p < 0.01); mean longitudinal systolic SR(2D), 0.73 +/- 0.21 vs. 0.97 +/- 0.22 x s(-1) (p < 0.01); mean longitudinal diastolic SR(2D), 0.94 +/- 0.34 vs. 1.01 +/- 0.23 x s(-1) (p > 0.01); mean radial systolic SR(2D), 1.20 +/- 0.15 vs. 1.45 +/- 0.32 x s(-1) (p < 0.01); mean radial diastolic SR(2D), 1.19 +/- 0.25 vs. 1.29 +/- 0.41 x s(-1) (p > 0.01); mean circumferential systolic SR(2D), -1.09 +/- 0.16 vs. -1.24 +/- 0.18 x s(-1) (p < 0.01); and mean circumferential diastolic SR(2D), -1.27 +/- 0.28 vs. -1.22 +/- 0.31 x s(-1) (p > 0.01). Marathon running promotes a varied echocardiographic response, with some functional parameters showing no change, some increasing, and some decreasing postexercise. This varied response likely reflects the complexities of cardiac function and highlights the need to adopt a multimodality approach when assessing cardiac function following 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 | 0.003 | 0.005 |
| 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 | 0.001 | 0.001 |
| 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".