1155Assessment of transmurality during lesion formation with electrograms
Bibliographic record
Abstract
Background: Real time lesion formation by means of the EGM analysis is needed after recent descriptions of the limitations of contact force catheters. A bipolar EGM amplitude (B-EGM) reduction of >75%, appearance of a QS pattern and disappearance of S-wave on the Unipolar-EGM (U-EGM) have been associated with transmurality of the lesion. These criteria are dependent on catheter orientation and the ability of the S waves to define local depolarization. A real-time assessment of lesion formation by means of EGMs is studied as a method for assessment of transmurality. Objectives: Describe real-time changes in EGMs to assess transmurality of the lesion. Methods: Eight Langendorff perfused rabbit (12) and pig (9) hearts were treated with 27 RF lesions at different powers and locations in the atrium and ventricle with assessment of lesion formation by EGM and confirmed with post-hoc histology. Recording of a EGM (perpendicular to the surface with interelectrode spacing of 2mm) in contact with the ablated tissue was performed. Assessment of Unipolar-EGM (filtered at 0.5 – 240 Hz) and Bipolar-EGM (filtered at 30Hz - 240Hz) was done qualitatively for pattern-identification (presence or absence of S wave in the unipolar recordings and QS pattern or non-QS pattern on filtered bipolar recordings) and automatically for peak-to-peak voltage amplitude measurement. Results: Transmurality was achieved in 15 of 27 lesions (55.6%). After 1W lesions delivered for 10 seconds (non-transmural) there was disappearance of the S wave in the U-EGM in 47% of the cases (7 of 15 lesions). Amongst all lesions at all powers, S wave in the U-EGM disappeared in 83% of non-transmural lesions indicating a poor specificity for assessment of transmurality. With regards to the B-EGM peak to peak voltage amplitude, after 1W lesions for 10 seconds (non-transmural) there was no change in the average voltage amplitude (-1%±57%, p=0.6) and B-EGM pattern was non-QS for all lesions. Amongst all lesions, peak to peak voltage amplitude was reduced by 80±21% in transmural lesions vs 60±17% in non-transmural lesions (p<0.05). A value of 78% reduction in peak to peak B-EGM voltage was linked to the highest AUC (0.86) when tracing a ROC-curve to assess for lesion transmurality (sensitivity of 73%, specificity of 83%). The filtered B-EGM was never a QS in transmural lesions. Conclusions: Assessment of lesion formation with traditional EGM criteria has poor predictive value for transmurality. A cutoff of >78% reduction in voltage peak to peak amplitude of a perpendicular B-EGM from baseline may be a useful tool to predict transmurality. In vivo, where catheter orientation is not reliable, an orientation-independent EGM recording may provide a better way to assess transmurality.
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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 | 0.000 | 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 | 0.000 |
| 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".