Canadian Trial of Physiological Pacing
Bibliographic record
Abstract
BACKGROUND: The Canadian Trial of Physiological Pacing (CTOPP) reported that the risk of stroke or cardiovascular death was similar between patients receiving ventricular versus physiological pacemakers at the end of the original follow-up period of 3 years. However, the occurrence of atrial fibrillation was significantly less frequent with physiological pacemakers. To assess a potential delayed benefit of physiological pacing, follow-up of patients in this study was extended to 6 years. METHODS AND RESULTS: A total of 1474 patients requiring a pacemaker for symptomatic bradycardia were randomized to receive ventricular and 1094 to physiological pacemakers. The primary outcome was stroke or cardiovascular death. The study was completed in July 1998, and follow-up was extended to July 2001. At a mean follow-up of 6.4 years, there was no difference between treatment groups in the primary outcome of cardiovascular death or stroke. There was no significant difference in total mortality or stroke between groups. There was a significantly lower rate of development of atrial fibrillation in the physiological group, with a relative risk reduction of 20.1% (CI, 5.4 to 32.5; P=0.009). CONCLUSIONS: The CTOPP extended study does not show a difference in cardiovascular death or stroke, or in total mortality, or in stroke between patients implanted with ventricular or physiological pacemakers over a mean follow-up of >6 years. However, there is a persistent significant reduction in the development of atrial fibrillation with physiological pacing.
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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 | 0.002 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.013 | 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".