Understanding ST depression in the stress-test ECG.
Bibliographic record
Abstract
OBJECTIVE: The electrocardiogram (ECG) obtained during stress testing often shows a typical pattern of primary ST depression. A similar pattern can occur in unstable angina. Current textbooks consider ST depression as a direct result of partial occlusion of a coronary artery. However, animal models could not reproduce this phenomenon. An alternative explanation for ST depression specific to stress testing involves global subendocardial ischemia. In this study, we evaluated both explanations with a realistic mathematical model of the human heart. METHODS: The ECG was simulated with an anisotropic reaction-diffusion model of the human heart and an inhomogeneous boundary-element model of the human torso. RESULTS: Limited subendocardial ischemic zones caused small ST depression in ECG leads not overlying the ischemic region. An ischemic zone of 50% transmural extent covering the entire left ventricular subendocardium caused an ST-depression pattern similar to that observed during stress test. CONCLUSION: In contrast to regional subendocardial ischemia, global subendocardial ischemia can explain ST depression in our model.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".