Cardiac resynchronization therapy offers no benefits in patients with narrow QRS (<120 ms): insights from the Evaluation of Resynchronization Therapy (EARTH) trial
Bibliographic record
Abstract
While the benefits of cardiac resynchronization therapy (CRT) are well established in patients (pts) with prolonged QRS duration, the benefits in patients with narrower QRS are less clear. Methods: The EARTH program consisted in 2 parallel multicenter randomized double-blind clinical trials that investigated the effects of CRT in 2 groups of pts: with QRS ≥ 120 ms and < 120 ms. Inclusion criteria were similar in both studies: clinical indication for implantable defibrillator, LVEF ≤35%, and a 6-minute walk distance (6-MWD) ≤400 meters. In both studies, pts underwent exactly the same investigations at baseline and after 6 months under simultaneous bi-ventricular pacing. The primary outcome was exercise capacity determined by a constant-load sub-maximal test performed at 75% of VO2 max. Secondary outcomes consisted of LV size and function assessed by echocardiography. Results: A total of 121 pts received active resynchronization therapy in the wide QRS group and 44 in the narrow QRS group. Baseline characteristics were similar except in terms of etiology of heart failure, LVEF and LV Volumes. After 6 months of CRT, the time (in minutes) covered during the sub-maximal exercise test, LVEF and LV volumes improved significantly in the wide QRS group, while the changes were not significant in the narrow QRS group (all P <0.05 between groups). Conclusions: In patients with HF and QRS < 120 ms, CRT does not improve functional capacity nor reverse LV remodelling parameters.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.002 | 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".