Basic EPS: How to Differentiate the Mechanisms of Narrow and Wide Complex Tachycardias?
Bibliographic record
Abstract
A systematic approach to differentiate tachycardia of narrow and wide complex QRS morphology includes physical signs/symptoms, simple ECG criteria, pharmacologic and stimulation maneuvers in the EP lab. If narrow QRS duration ( 100 bpm in adults) is shown on 12 lead ECG, then additional ECG criteria such as RR regularity, RP/PR relation, onset/offset of tachycardia and response to vagal maneuvers or adenosine is examined to differentiate between AVNRT, pathway mediated tachycardia or atrial tachycardia. If wide complex tachycardia (WCT) is shown, then QRS morphology (compared with sinus), evidence of AV dissociation, QRS concordance pattern, fusion/capture beats are useful to differentiate if WCT is SVT with aberration, VT or preexcited tachycardia. Stimulation maneuvers include response of tachycardia to extrastimului, reset response to entrainment pacing. A His-refractory PVC delivered into SVT that is able to advance retrograde atrial activation timing with the same tachycardia sequence and resets or terminates tachycardia is diagnostic proof of a pathway mediated SVT and excludes AVNRT. A delta-VA of <85 ms or PPI-Tachy CL of <115 ms after ventricular entrainment pacing favors pathway mediated SVT over AVNRT. Post pacing VAAV response is more consistent with atrial tachycardia. Measurement of the HV interval during WCT helps to differentiate the mechanism, HV that is the same or longer than in sinus is consistent for SVT with aberration.
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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 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.003 | 0.008 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.004 | 0.006 |
| Insufficient payload (model declined to judge) | 0.004 | 0.007 |
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".