Acute Electrical Synchronization Achieved With Dynamic Atrioventricular Delays During Biventricular and Left Ventricular MultiPoint Pacing
Bibliographic record
Abstract
Background Cardiac resynchronization therapy (CRT) response relies on 2 factors: when and where to pace. These factors may be enhanced by dynamic atrioventricular delays (AVDs) (eg, SyncAV CRT, Abbott Cardiovascular, Abbott Park, IL) and multisite left ventricular (LV) pacing (eg, MultiPoint Pacing [MPP], Abbott). Their individual and combined synchronization contributions have not been evaluated across a comprehensive spectrum of pacing configurations. The objective is to distinguish the acute electrical synchrony achieved by static vs dynamic AVDs, single-site vs multisite LV pacing, and with vs without right ventricular (RV) pacing. Methods CRT-indicated patients with left bundle branch block (LBBB) and intact atrioventricular (AV) conduction (PR < 250 ms) were enrolled and evaluated during implant. Acute changes in 12-lead electrocardiographic (ECG) QRS duration (QRSd) were evaluated during intrinsic conduction, biventricular pacing (BiV), biventricular MPP, LV-only single-site pacing (LVSS), and LV-only MPP (LVMPP). CRT modes were evaluated with static AVDs and optimized SyncAV AVDs. Results CRT implant and QRSd evaluation were completed in 85 patients (71% male, 34% ischemic, 179 ms PR). The median intrinsic QRSd of 165 ms was reduced by BiV, MPP, LVSS, and LVMPP without SyncAV to 144 ms (by 14%), 142 ms (16%), 155 ms (8%), and 149 ms (12%), respectively ( P < 0.01 vs intrinsic). BiV + SyncAV, MPP + SyncAV, LVSS + SyncAV, and LVMPP + SyncAV reduced the intrinsic QRSd significantly further to 128 ms (by 23%), 124 ms (26%), 131 ms (21%), and 129 ms (24%) ( P < 0.0001, each corresponding pair). Conclusions MPP combined with SyncAV achieved the narrowest QRSd, in the overall population and in the most patients, by delivering ventricular pacing from all available sites (RV + LV1 + LV2) while timed with dynamic AVDs. Clinical Registration Number NCT03567096.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".