Abstract 14654: Does Pharmacological Ventricular Rate Control Mitigate AF-Induced Remodeling in the Absence of Tachycardiomyopathy?
Bibliographic record
Abstract
Introduction: Atrial fibrillation (AF) causes electrical and structural remodeling (primarily fibrosis) that promotes AF progression. Pharmacological ventricular rate control is used to prevent tachycardiomyopathy, but whether it can directly interfere with AF-associated structural remodeling has never been tested. This study was designed to evaluate the effect of pharmacological ventricular rate control during AF on substrate progression in dog models. Methods: Four groups of dogs (N=6/group) were studied: AT-P dogs: right atrial tachypacing at 600 beats/min (AT-P) to induce sustained AF for 3 weeks without other intervention; AT-P+D dogs: AT-P X 3 wks with diltiazem-CD 360 mg/day to achieve rate control; AT-P+ABL dogs: AT-P X 3 wks with AV node ablation and ventricular backup pacing (80 bpm); and non-paced Sham dogs. Results: Ventricular response rate averaged 172±16 (mean ±SE), 156±10 and 142±6 beats/min on days 1, 7 and 21 in AT-P dogs, vs 102±9**, 105±8* and 99±8** respectively (**p<0.01 for each) in AT-P+D dogs. LVEF decreased slightly (from 55.8±1.3% at baseline to 52.4±2.7% in AT-P, P=NS; 45.2±2.0%* in AT-P+D, *P<0.05; and 51.0±2.8% in AT-P+ABL, P=NS). LA dimension increased slightly but significantly (from 20.2±0.6 mm at baseline to 23.3±1.3 mm* in AT-P, 23.4±1.0 mm* in AT-P+D and 23.1±0.7 mm* in AT-P+ABL). At terminal open chest study, while overall conduction velocity (CV) was not significantly different (86±2 cm/sec in AT-P, 91±7 cm/sec in in AT-P+D, 87±3 cm/sec in AT-P+ABL and 96±6 cm/sec in Sham group), CV heterogeneity (reflecting local conduction slowing) was greater in AT-P (4.1±0.4) vs other groups: 2.2±0.2* in AT-P+D, 2.5±0.1* in AT-P+ABL and 2.6±0.3* in Sham group. Atrial ERP was reduced vs Sham (115 ±10 ms) in all tachypaced groups: 51±4** ms in AT-P, 82±7** ms AT-P+D, 58±4** ms ATP+ABL. Mean duration of AF induced by burst pacing was greater in AT-P (1065±258 sec) vs AT-P+D (229±77** sec), AT-P+ABL (378±130* sec) and Sham (45±8** sec). LA Collagen-1 mRNA expression was significantly greater in AT-P (19.0±3.3 A.U.) vs AT-P+D (6.7±0.3 A.U.*). Conclusions: Pharmacological rate control prevents progression of the AF substrate due to structural remodeling. This is a novel consideration in the use and targeting of rate control therapy.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| 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".