Non-sustained wide complex tachycardia: an underappreciated sign to aid in diagnosis
Bibliographic record
Abstract
AIMS: The electrocardiographic (ECG) signs used to differentiate ventricular tachycardia (VT) from supraventricular tachycardia (SVT) with aberrancy are specific but not highly sensitive. The purpose of this study was to define the utility of an underappreciated form of atrioventricular (AV) dissociation at the onset of tachycardia, a single dissociated P wave, in the differentiation of non-sustained monomorphic wide complex tachycardia (WCT) in hospitalized patients. METHODS AND RESULTS: We prospectively analysed tracings from 102 consecutive hospitalized patients who had an episode of non-sustained (≥5 beats, <30 s), monomorphic, WCT (≥100 b.p.m.) on telemetry. WCT was classified as VT, SVT with aberrancy, or undifferentiated WCT based on predefined criteria. Of 102 patients with WCT, 3 (3%) had SVT with aberrancy, 43 (42%) had an undifferentiated WCT, and 56 (55%) had VT. ECG evidence of a single dissociated P wave at the onset of tachycardia (i.e. AV dissociation at the onset) was identified in 29 patients (28%) compared with less frequent traditional signs of VT including second-degree ventriculoatrial (VA) block in 18 patients (18%), AV dissociation during tachycardia in 17 patients (17%), fusion beats in 10 patients (10%), and capture beats in 3 patients (3%). On multivariate analysis, only the prematurity index predicted the occurrence of AV dissociation at the onset of the tachycardia (odds ratio 1.239, 95% confidence interval 1.033-1.486, P = 0.021). CONCLUSION: When evaluating WCT in hospitalized patients, a single dissociated P wave at the onset of tachycardia is an easily recognizable diagnostic sign of VT, and is observed more frequently than the other accepted criteria for VT.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".