Abstract 9323: Localized Reentrant Activation in the Left Atrium During Human Atrial Fibrillation: Relationship to Complex Fractionated Atrial Electrograms and Low Voltage Zones
Bibliographic record
Abstract
Introduction: In humans, the existence of reentrant sources maintaining AF and the underlying electroanatomic substrate has not been well defined. Our objective was to determine the prevalence of localized reentrant activation in the left atrium (LA) during human AF and whether complex fractionated atrial electrograms (CFAEs) or low voltage areas co-localize with these sites. Methods: We prospectively studied 32 patients (57±8yrs, 88% persistent AF) undergoing AF catheter ablation. Bipolar EGMs were recorded for 2.5sec during AF using a roving 20-pole circular catheter in the LA. Reentrant activation was defined as sequential temporal activation of bipoles around the circular catheter. Bipolar EGM fractionation index (FI) and bipolar voltage were used to define CFAEs (FI>7) and low voltage areas (<0.1 mV), respectively. Results: In 21 (66%) patients, 47 reentrant sites were identified. Few (9%) lasted 2.5sec (CL 183±6ms) (Figure, panel A and C), while the majority (91%) were nonsustained (duration 610±288ms, CL 149±11ms) (Figure, panel B and D). Reentrant sites were most common in the PV antrum (71%) and posterior LA (25%). CFAEs were recorded from 18±12% of LA area and most (92±7%) were not associated with reentrant sites. However, 85% of reentrant sites contained CFAEs (Figure, Panel B and D). Very low voltage (<0.1mV) areas comprised 12±10% of LA area and were present in 23% of reentrant sites. Conclusions: In patients with predominantly persistent AF, localized reentrant activation is commonly present, but tends to be transient (<1 second). Although most CFAEs do not co-localize with reentrant sites, the high prevalence of CFAEs and very low voltages within the circuit may indicate slow conduction in diseased myocardium that is necessary for sustaining reentry.
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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) | 0.003 | 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".