Prognostic significance of ischemic electrocardiographic changes during stress testing in patients with normal nuclear myocardial perfusion imaging
Bibliographic record
Abstract
OBJECTIVE: To evaluate cardiovascular outcomes in patients with normal nuclear myocardial perfusion imaging, but ischaemic electrocardiogram changes during pharmacological or exercise stress tests. METHODS: The retrospective study was conducted at the Aga Khan University Hospital, Karachi, and comprised data of patients who underwent either pharmacological or exercise stress myocardial perfusion scan and had a normal scan with ischaemic electrocardiogram changes between January 2013 and December 2014. All cardiac events, including angina, myocardial infarction, heart failure, coronary revascularisation and cardiac death, as well as non-cardiac deaths were noted. Data was analysed using STATA 14.2. RESULTS: Of the 2770 patients whose data was initially checked, 296(10.6%) developed ischaemic electrocardiogram changes during the stress test but had normal myocardial perfusion scan. Of them, 181(61%) patients were male, and the overall mean age was 62±15 years. Follow-up data was available for 280(94.5%) of these patients, with a mean follow-up of 48±7 months. Of these patients, 8(2.8%) died, and 1(0.3%) of them died due to inferior wall myocardial infarction. Myocardial infarction was found in 2(0.7%) patients, and 1(0.3%) patient was hospitalised with heart failure. Also, 12(4.3%) patients underwent revascularization for stable angina, 9(3.2%) underwent percutaneous transluminal coronary angioplasty, and 3(1.07%) needed coronary artery bypass grafting. CONCLUSIONS: Ischaemic electrocardiographic changes during stress testing in patients with normal myocardial perfusion scan were not associated with adverse outcomes, and the risk of cardiovascular events was relatively low for an intermediate follow-up period.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".