Single chamber ventricular compared with dual chamber pacing: a review.
Bibliographic record
Abstract
Since its introduction in the 1950s, the cardiac pacemaker has become increasingly sophisticated in an attempt to mimic normal cardiac physiology. Rapidly evolving pacing technology has seen pacemakers evolve from crude, fixed-rate, single chamber ventricular devices to dual chamber rate-adaptive units. While there is indirect evidence that supports the use of dual chamber pacing in the vast majority of patients, it is still unclear whether these newer, more expensive devices afford a significant morbidity and mortality benefit over single-chamber, ventricular, rate-adaptive pacemakers. A review of three large, randomized trials failed to demonstrate a clear benefit of dual chamber or atrial-based pacing over single chamber ventricular pacing for the majority of cardiovascular outcomes (heart failure, stroke and mortality), with the possible exception of atrial fibrillation. Information is also needed on the potential protective effects of atrial-based pacing over dual chamber pacing in elderly patients with sinus node dysfunction. Longer follow-up periods may be necessary to determine whether there are any mortality benefits associated with dual chamber pacing. Additional confirmation of benefits of dual chamber pacing may be provided by other ongoing prospective trials.
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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 | 0.003 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.005 | 0.002 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.008 | 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".