An update on clinical trials in pacing: is dual chamber pacing better?
Bibliographic record
Abstract
PURPOSE OF REVIEW: As pacemaker technology has increased in complexity and now offers a variety of additional capabilities, there is uncertainty as to which pacing mode offers more benefit-dual-chamber or single-chamber. RECENT FINDINGS: Two large-scale randomized trials, the Canadian Trial of Physiologic Pacing and the Mode Selection Trial, demonstrated that dual-chamber pacing does not reduce the incidence of stroke or improve survival when compared with ventricular pacing. However, dual-chamber pacing does reduce the incidence of atrial fibrillation and in patients with sinus node dysfunction, reduces heart failure symptoms when compared with ventricular pacing. The modest results of these trials were unexpected when viewed in the context of the very favorable retrospective studies. SUMMARY: A rethinking of the physiology of cardiac pacing has led to the concept that although atrioventricular synchrony supports an improvement in cardiac output and ventricular pressures, these favorable hemodynamics may be attenuated by ventricular dyssynchrony from right ventricular apical pacing. In patients with a reduced ejection fraction, this dyssynchrony may be especially detrimental. Two trials (DANPACE and SAVE-PACE) are currently underway that will clarify the clinical significance of reducing forced ventricular desynchronization. The results of these trials may direct pacemaker physicians away from the right ventricular apical lead toward a new imperative of atrioventricular and right ventricular-left ventricular synchrony.
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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 | 0.072 | 0.222 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.012 | 0.003 |
| Bibliometrics | 0.006 | 0.010 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.008 | 0.011 |
| Open science | 0.004 | 0.002 |
| Research integrity | 0.012 | 0.010 |
| Insufficient payload (model declined to judge) | 0.008 | 0.003 |
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".