The pharmacological response of ischemia-related atrial fibrillation in dogs: Evidence for substrate-specific efficacy
Bibliographic record
Abstract
OBJECTIVE: Acute atrial ischemia produces a substrate for atrial fibrillation (AF) maintenance, but the response of this substrate to antiarrhythmic-drugs has not been defined. The present study assessed the effects of class 1-4 antiarrhythmic-drugs on the electrophysiological consequences of acute atrial ischemia, and compared effects in ischemic AF with those in vagal AF. METHODS AND RESULTS: Isolated atrial ischemia was created by ligating a right coronary artery branch perfusing the right atrial free wall. Experiments were performed in dogs treated with loading and maintenance doses of flecainide (class 1; n=5), nadolol (class 2, n=7), dofetilide (class 3, n=5), or diltiazem (class 4, n=7) prior to coronary artery occlusion. Dogs subjected to coronary occlusion without pre-treatment (n=10) served as controls. Coronary artery occlusion substantially increased AF duration, e.g. from 7+/-4 s (pre-ischemic baseline) to 876+/-245 s at 3 h of ischemia, and caused substantial ischemic zone conduction slowing. Diltiazem and nadolol prevented AF promotion (AF durations 12+/-8 s and 4+/-1 s at 3 h of ischemia respectively; each p<0.001 vs control) and suppressed ischemic conduction slowing. Flecainide and dofetilide failed to prevent ischemia-induced AF promotion (e.g. AF duration at 3-hour ischemia 779+/-417 and 801+/-414 respectively, p=NS vs control) and failed to alter ischemia-induced conduction slowing. A different pattern of response occurred with vagal AF: flecainide was highly effective in reducing vagal AF duration; dofetilide, diltiazem, and nadolol were ineffective. CONCLUSIONS: Beta-blockade and Ca(2+) antagonism suppress the arrhythmic consequences of acute atrial ischemia, whereas Na(+) channel or K(+)-channel block are ineffective. These results are relevant to understanding the effects of different classes of antiarrhythmic-drugs on AF occurring in coronary disease patients.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.026 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".