Abstract 4138912: Clinical outcomes of cardiac synchronization with or without an implantable cardioverter defibrillator based on pooled data from 5 clinical trials: a patient-level meta-analysis
Bibliographic record
Abstract
Background: Cardiac resynchronization therapy (CRT) is a well-established therapy for patients with heart failure with reduced ejection fraction (HFrEF) and wide QRS. Whether CRT-defibrillators (CRT-D) reduce mortality more than CRT-pacemakers (CRT-P) remains controversial. Aims: To compare the clinical outcomes of CRT-D vs CRT-P using data from 5 landmark CRT trials, both overall and stratified by etiology of cardiomyopathy (ischemic vs non-ischemic), sex (male vs female), age (≥ 70 y/o vs < 70 y/o), and QRS morphology (IVCD, LBBB, RBBB). Methods: We performed a meta-analysis of patient level data from 5 prospective CRT trials (MIRACLE, REVERSE, RAFT, COMPANION and MADIT-CRT). Inclusion criteria were CRT-P vs CRT-D status (randomized comparison only in COMPANION), age ≥ 18 y/o and LVEF ≤ 35%. Exclusion criteria included secondary prevention ICD, QRS < 120ms, pacemaker upgrade, ventricular pacing indication, or missing data. Primary outcome was composite of time to heart failure hospitalization (HFH) or all-cause death. Secondary outcomes were time to HFH and death. Outcomes were analyzed using a frequentist Cox Proportional Hazards mixed effects model adjusted for 17 variables. Results: A total of 3407 patients met inclusion criteria. Relative to patients with CRT-P (n=843), those with CRT-D (n=2564) were of similar age (66 y/o, p=0.5), less often female (24% vs 34%, p<0.001), and more often had ischemic cardiomyopathy (59.4% vs 52.4%, p<0.001), Fig 1A. Primary outcome was similar across groups (HR 0.902 [0.752, 1.081], p=0.26), but all-cause mortality was lower with CRT-D vs CRT-P (HR 0.77 [0.603, 0.983], p=0.036), Fig 1B. Interaction analyses suggested lower all-cause mortality with CRT-D vs CRT-P in patients with non-ischemic cardiomyopathy (HR 0.502 [0.346, 0.726], p=0.0003) and patients age ≥70 y/o (HR 0.679 [0.502, 0.919], p=0.012), with significance preserved after Bonferroni correction (Fig 1B). Conclusion: In patients receiving CRT for HFrEF, those with CRT-D had lower all-cause mortality than patients with CRT-P, driven mainly by a lower mortality with CRT-D in older patients and those with non-ischemic cardiomyopathy. No significant interactions were noted between ICD&sex or ICD&QRS morphology.
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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 | 0.017 | 0.026 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.016 | 0.055 |
| Bibliometrics | 0.004 | 0.005 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.005 | 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".