Abstract 18317: Impact of Pulmonary Valve Replacement on Right Ventricular Myocardial Deformation in Repaired Tetralogy of Fallot
Bibliographic record
Abstract
Introduction: Pulmonary regurgitation is common following tetralogy of Fallot (TOF) repair and leads to progressive right ventricular (RV) dilatation and dysfunction. There is limited data on ventricular remodeling and adaption following surgical pulmonary valve replacement (PVR), especially beyond the short-term. Hypothesis: Our objective is to assess medium-term effects of PVR on right ventricular mechanics in patients with surgically repaired TOF. Methods: Speckle-tracking echocardiography was performed on pre-operative and post-operative echocardiograms in 50 patients with repaired TOF who underwent surgical PVR. RV global and segmental myocardial deformation parameters were assessed. Transthoracic studies 2.1±2.1 months pre-PVR, 2.23±0.61 months post-PVR (early follow-up) and 14.9±3.8 months post-PVR (medium-term follow-up) were analyzed. Results: The mean age at PVR was 12.6±3.3 years. Global RV longitudinal strain fell from -19.2%±2.7% to -16.8%±2.6% at early follow-up (p<0.001) but increased by late follow-up to -21.9%±3.1% (p<0.001). Basal segmental RV longitudinal strain showed a similar early reduction in strain followed by improvements late post-operatively (p<0.001). Mid-segmental RV longitudinal strain improved by late post-operative follow-up (p=0.002), whereas apical segmental RV strain increased in the early post-operative period (p=0.004). There was a weak inverse correlation between pre-operative RV indexed end-diastolic volumes and RV mean longitudinal strain (R2=0.383). Conclusion: Although an early reduction in RV longitudinal strain occurs following PVR, the volume unloading effects of PVR has a significant effect on late RV remodelling as reflected by improvements in global RV longitudinal, basal and mid segmental strain late post-PVR. The effects of reversed remodelling of the RV may have important clinical implications towards determining the optimal timing of PVR in this subset of patients.
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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".