Criteria in standard ECG to guide conduction system pacing implants
Bibliographic record
Abstract
Abstract Conduction System Pacing (CSP) is gaining acceptance when high ventricular pacing burden is expected, and as an alternative to cardiac resynchronization. Current accepted criteria to ascertain CSP proper lead placement requires an EP system, not widely available. There are multiple ECG only criteria not currently validated for CSP implantation. We extracted all CSP attempted implants. Various accepted criteria for CSP capture were evaluated for each patient, along with other ECG only criteria: T wave polarity in lateral leads (V5-V6); T wave polarity in D1, terminal S wave in lateral leads; terminal S wave in D1; and an initial r wave in V1. A cohort of 482 consecutive patients was evaluated, where 36% were women. Mean age was 77.3 y.o. (± 8.9 years; range 22-98 y.o.). Implant indications included: sick sinus (26.3%), AV block (34.9%), abnormal conduction induced cardiomyopathy (26.1%), AV node ablation (9.1%) and LBBB only (0.8%). Medtronic 3830 leads were mostly implanted. A His pacing was targeted in 5.2% of patients, and 51.4% had pre-implant narrow QRS. Leads were directed anteriorly, posteriorly and mid-septal in 28.3%, 18.6%, and 53.1% of cases, respectively (based on inferior lead polarities). A QRS (from the pacing spike) of 140ms or less was achieved in 60.0% of implants, a LVAT lesser than 75ms in 47.7% (lesser than 85ms in 78.1% of patients and impossible to evaluate in 6.0% of patients (due to Q-S in V6)). A V6-V1 interpeak interval greater than 33ms was achieved in 54.0% of patients (the criterion was impossible to measure in 36.3% of patients). When comparing possible ECG parameters which may guide CSP implants, V5-V6 normal T wave repolarization and terminal S waves in V5-V6 where found to be most helpful and provides another tool to ascertain CSP capture when r’/R’ are not seen (mostly in anterior oriented positions) or V6-V1 inter-peak is impossible to measure (lack of either positive V5-V6 or visible r’/R’ in V1).Table1
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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 | 0.003 | 0.011 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.004 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.003 |
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".