Abstract 9717: Hypertension-Induced Atrial Remodeling Promotes Atrial Fibrillation Stabilization Upon Tachyarrhythmia Onset
Bibliographic record
Abstract
Background: Hypertension (HT) is a major risk factor for atrial fibrillation (AF) but the underlying mechanisms are poorly understood. We hypothesized that HT produces an AF-stabilizing influence that favors faster progresion of spontaneous AF-maintenance when atrial tachyarrhythmia (AT) begins. Methods: HT was induced in dogs (n=6) by left nephrectomy and right renal artery constriction (1K1C). Sham operated dogs with the same surgery but no nephrectomy or artery constriction (n=5) were controls. Beginning 28 days from surgery, AT-pacing (ATP, 600 bpm) was started for 7 days. Serial atrial ERP measurement and AF induction was performed at days 7, 14, 28, 29, 30, 32 and 35 from surgery. Final open chest EPS was performed at day 36. Results: Systolic blood pressure (SBP) of HT dogs increased beginning at day 7 post 1K1C surgery (baseline 128±4 mm Hg; 7-d 183±6*, 28-d 176±10* mmHg; * p<0.01 vs. baseline). SBP of sham dogs remained constant (baseline 133±4 mm Hg; 7-d 128±3, 28-d 126±6 mmHg). Mean AF duration (10 Hz burst pacing induced) increased marginally in HT dogs pre-ATP (Figure), but substantially after 1 and 2 days ATP vs control. At open-chest EPS, there were no differences in AF vulnerability to premature extrastimuli (HT, 69±5% vs. Sham, 70±11%; p=NS), AF duration (HT, 1501±273 sec vs. Sham, 1458±342 sec; p=NS) or regional ERP heterogeneity. HT dogs showed increased atrial conduction heterogeneity (heterogeneity index in HT, 2.01±0.10 vs. sham, 1.50±0.08; p<0.01), associated with significant downregulation of connexin (Cx) 43 expression (by 57% + , + p<0.05) but no change in Cx40 expression. Heart to body weight ratio increased in HT (9.7±0.4 vs. 8.5±0.2 + ), reflecting LVH. Conclusions: HT alone produces modest AF promotion, but changes caused by HT accelerate AF stabilization once initiated, increasing vulnerability to prolonged AF. The AF-promoting effects of hypertension are related to conduction abnormalities, possibly caused by connexin downregulation.
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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) | 0.000 | 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 | 0.001 |
| 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".