Abstract 2006: Contrast-Enhanced MRI in the Hyperacute Phase of ST-Elevation Myocardial Infarction Predicts Late Myocardial Recovery
Bibliographic record
Abstract
Left ventricular ejection fraction (EF) late after myocardial infarction determines whether patients will benefit from cardioverter/defibrillator (CV/D) implantation. At present, patients with acute ST elevation myocardial infarction (STEMI) are evaluated several months later to determine EF and CV/D indication following initial recovery. We determined whether contrast-enhanced MRI (CE-MRI) in the hyperacute phase of STEMI could predict late myocardial recovery. 50 patients with STEMI underwent CE-CMR within 12 hours of primary angioplasty (median 4h). All had follow-up CE-CMR >6 months later. Global and segmental left ventricular function, morphology, perfusion and necrosis were determined and assessed by validated techniques (QMass, Medis, the Netherlands). In the hyperacute phase of STEMI, a greater cardiac output (4.2 vs 3.4 L/min, p=0.01) was measured due to significantly greater heart rate (72 vs 57 bpm, p<0.01) despite similar stroke volumes (59 vs 60mL, p=NS) compared to >6 months later. On average, LVEF did not significantly change from hyperacute STEMI to recovered phase (51 vs 54%, p=NS) but systolic wall thickening increased on average from 41 to 50% (p=0.01) due to compensatory increased systolic thickening of non-infarct related segments. LV mass decreased from 120 to 105 g (p=0.01) due to a decrease in mean wall thickness driven by infarct segment wall thinning (9.2 vs 8.4mm, p<0.01). Microvascular function improved significantly (time to 50% enhancement on first-pass CE-MRI: 24.3 vs 21.7ms, p=0.03). Contrary to prior reports of “scar shrinkage” comparing necrosis in the first week after STEMI and 6 months later, necrosis relative to total myocardial volume did not differ between the hyperacute phase and >6 months (20 vs 18%, p=0.46). Furthermore, the transmural extent of necrosis, a potent predictor of functional recovery, did not significantly change from the hyperacute to the recovered phase of STEMI (mean 17 vs 14%, p=0.38). CE-MRI in the hyperacute phase of STEMI is a powerful predictor of long-term myocardial function and necrosis which could prove useful for very early risk stratification and future targeting of appropriate therapies.
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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) | 0.004 | 0.001 |
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".