Effects of Atrioventricular Optimization on Left Ventricular Reverse Remodeling With Cardiac Resynchronization Therapy: Results of the SMART-CRT Trial
Bibliographic record
Abstract
Background: The role of atrioventricular optimization (AVO) to improve cardiac resynchronization therapy outcomes remains controversial. Previous post hoc analyses of a multicenter trial showed that measures of electrical dyssynchrony (right ventricular–left ventricular [LV] or LV electrical delay durations) are associated with patients who benefit from AVO. Methods: This was a global, multicenter, prospective, randomized trial of de novo cardiac resynchronization therapy implant patients with an right ventricular–LV duration ≥70 ms to determine whether AVO results in greater reverse remodeling. Patients were randomized 1:1 for either an AVO algorithm (SmartDelay) that determines atrioventricular delay and pacing chamber, biventricular or LV only, or a fixed atrioventricular delay of 120 ms with biventricular pacing. Paired echocardiograms performed at baseline and 6 months were evaluated. The primary end point was echocardiographic cardiac resynchronization therapy response, defined dichotomously as a >15% reduction in LV end-systolic volume. Results: A total of 310 patients (n=120 women) were randomized and had completed 6 months of follow-up. The echocardiographic cardiac resynchronization therapy response rate did not statistically differ between the groups (SmartDelay, 74.8%; fixed, 67.7%; P =0.17). Analyses of prespecified secondary end points demonstrated significant improvements in the absolute (median: SmartDelay, −41.0 mL; fixed, −33.0 mL; P =0.01) and relative change in LV end-systolic volume (SmartDelay, −38.3%; fixed, −27.8%; P =0.03) for patients with SmartDelay optimization. Similar results were observed for the relative improvement in LV ejection fraction (SmartDelay, 46.7%; fixed, 32.1%; P =0.050); absolute improvement in LV ejection fraction trended to be higher with SmartDelay ( P =0.06). Conclusions: Analysis of reverse remodeling parameters demonstrated that AVO via SmartDelay, relative to the nonoptimized fixed atrioventricular delay comparator group, improved absolute and relative changes in LV function in patients with longer right ventricular–LV duration. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03089281.
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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 | 0.001 | 0.001 |
| 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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".