Abstract 17313: Myocardial Remodeling in Atrial Fibrillation is Not Associated With Supraventricular or Ventricular Ectopic Activity: Results From a Cardiac Imaging Study
Bibliographic record
Abstract
Background: Myocardial remodeling in atrial fibrillation (AF) is a continuum of structural, hemodynamic, and electrophysical changes that often coexist in a complex pathophysiological interplay. Purpose: The aim of this study was to evaluate whether cardiac magnetic resonance imaging (CMR) derived myocardial strain, by tracking subtle alterations in myocardial function, was associated with premature atrial (PAC) and ventricular (PVC) complexes, detected by 7-day Holter-monitoring. Methods: A total of 95 patients (mean age 63±8.5 years, 52% male) with a history of paroxysmal (51%) or persistent AF (49%) underwent CMR and 7-day Holter-monitoring during sinus rhythm. Left atrial measures, including volume, ejection fraction, peak systolic longitudinal, radial and circumferential strain were assessed using cine CMR feature tracking by commercially available software (Circle, Calgary, Canada). Holter-monitoring was used to determine heart rate and rhythm, including the presence of PACs and PVCs. The associations between strain variables and Holter-variables were examined using multivariable linear regression, adjusted for age, sex, and AF type. Results: Left atrial end-diastolic volume was significantly increased, particularly in patients with persistent AF, when compared with healthy controls (persistent AF 132±32 ml vs. healthy 77±14 ml). Similarly, left atrial ejection fraction was significantly reduced in persistent AF as compared with normal reference values (48±10 ml vs. 54±10 ml). There were no significant associations between CMR strain parameters and average PACs per hour, average PVCs per hour, average PACs per sinus beats per hour or average PVCs per sinus beats per hour. These associations remained unaltered after adjusting for age, sex, and AF type. Finally, no significant interactions with AF type were found. Conclusions: Despite significant myocardial remodeling in left atrium shown by increased end-diastolic volume and decreased left atrial ejection fraction, there was no correlation with increased ectopic activity as assessed by 7-day ambulatory Holter monitoring. Image
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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 | 0.002 |
| 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) | 0.002 | 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".