An Alternative Method of Assessing Bidirectional Block for Atrial Flutter
Bibliographic record
Abstract
BACKGROUND: The success of cavotricuspid (CTI) ablation depends on the achievement of bidirectional block. Previous investigators have shown that right ventricular (RV) pacing can replace proximal coronary sinus (pCS) pacing in assessing clockwise CTI conduction block. OBJECTIVE: We sought to assess bidirectional conduction using antegrade (A-V) and retrograde (V-A) conduction times in the absence of coronary sinus (CS) pacing. METHODS: Counterclockwise CTI conduction block was evaluated using conduction time to the QRS from 2 pacing sites (immediately lateral and further lateral to the CTI). This was compared to the conduction time to the pCS with pacing from the same 2 lateral points. This was measured prior to ablation in 7 patients and 41 patients following ablation. To evaluate clockwise CTI conduction block we measured the conduction time to the 2 lateral sites during RV pacing and pCS pacing. This was measured in 7 patients prior to ablation and 16 patients following successful ablation. RESULTS: The abbreviated technique correctly indicated the presence or absence of bidirectional block in all patients. Furthermore, conduction times as assessed by the 2 methods correlated well both before and after creation of bidirectional block (correlation coefficients prior to ablation: clockwise direction r = 0.92, P = 0.0036; counterclockwise direction r = 0.86, P = 0.0132; after ablation: clockwise direction r = 0.82, P = 0.0001; counterclockwise direction r = 0.91, P < 0.0001). CONCLUSION: Bidirectional CTI conduction block can be successfully demonstrated using A-V and V-A conduction without the need for CS pacing. Patients need, however, to have intact A-V and V-A AV nodal conduction.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".