Abstract 18153: Abnormal Dynamic Myocardial Response to Exercise Despite Normal Resting Ejection Fraction in Childhood Cancer Survivors Treated With Anthracyclines
Bibliographic record
Abstract
Introduction: There are limited data on myocardial systolic & diastolic response to exercise in pediatric cancer survivors treated with anthracycline. We used exercise echocardiography to evaluate ventricular systolic and diastolic reserve in these patients. Methods: 50 children (age 14.4±2.4 years) who had received anthracycline treatment with median dose 178mg/m 2 (range 60-450) underwent stepwise exercise echocardiography at 9.3±2.9 years after end of therapy, and compared with 50 normal controls. All subjects had normal resting LVEF. Peak systolic (s’) & early diastolic (e’) myocardial velocities in the LV & RV lateral wall, & basal septum were measured at rest & during exercise using color TDI. Measurements of myocardial isovolumic acceleration (IVA) at incremental heart rates (HR) were used to study force-frequency relationships (FFR). Results: At rest, LV systolic parameters were preserved in patients; septal e’ was significantly lower compared to controls (10.4±1.9cm/s vs 11.4±1.9cm/s; p =0.009). At peak exercise, LV & RV lateral wall, & basal septal e’ velocities were lower in patients (17.4±3.8cm/s vs 19.6±3.1cm/s, p =0.002; 21.5±1.6cm/s vs 22.3±1.9cm/s, p =0.02; & 16.3±2.4cm/s vs 18.7±2.7cm/s, p <0.001; respectively) & the slopes of change with increasing HR were significantly lower in patients for LV lateral e’ [EST (SE): +0.68 (0.08) vs +0.85 (0.05) cm/s per 10 bpm; p <0.001], RV lateral e’ [+1.47 (0.05) vs 1.69 (0.06) cm/s per 10 bpm; p <0.001] & basal septum e’ [+0.50 (0.05) vs 0.58 (0.05) cm/s per 10 bpm; p =0.001]. During exercise, peak contractile force developed by patients was significantly lower (LV IVA 5.12±1.85m/s 2 vs 6.75±3.28m/s 2 ; p =0.004). FFR analysis showed reduced rate-contractility trajectory in patients [+0.202 (0.008) vs +0.217 (0.008) natural log m/s 2 per 10 bpm; p =0.001]. Conclusions: Long-term survivors of anthracycline-treated pediatric cancer have reduced systolic & diastolic myocardial reserve in response to 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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| 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) | 0.002 | 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".