Amplitude spectrum area to predict true shock-refractory ventricular fibrillation during basic life support-treated out-of-hospital cardiac arrest
Bibliographic record
Abstract
AIM: Refractory ventricular fibrillation (VF) is associated with decreased survival. Guideline definition of refractory VF, i.e. a VF persisting after 3 shocks, includes cases of true shock-refractory VF or recurrent VF with transient defibrillation response. Predicting true shock-refractory VF before repeated shock failure could prioritize targeted interventions to improve out-of-hospital cardiac arrest (OHCA) outcomes. We hypothesized that amplitude spectrum area (AMSA) may predict cases of true refractory VF. METHODS: ECGs recorded by automated external defibrillators were obtained from OHCAs in 8 cities in Italy. A 2-second VF window before each defibrillation was analyzed to calculate Amplitude Spectrum Area (AMSA). Defibrillation success was defined by occurrence of a perfusing rhythm, while refractory VF was defined as: "pragmatic-refractory" (based on guideline definition); or within this category, as "True shock-refractory", if VF continuously persisted over the period needed to deliver the first 3 shocks; or "refractory-recurrent", if VF recurred after any of the first three shocks transiently terminated VF. RESULTS: 1646 OHCAs with shockable presenting rhythm were included, 360 (22 %) of whom met the definition of pragmatic-refractory VF. Among the 360 cases of pragmatic-refractory VF, 18 % were true shock-refractory and 82 % were refractory-recurrent VF. AMSA was significantly lower in true shock-refractory VF than in refractory-recurrent VF. A lower first AMSA was associated with occurrence of true shock-refractory VF (aOR:0.81; 95 %CI: 0.73-0.88; p < 0.0001). CONCLUSIONS: Lower AMSA is associated with true shock-refractory VF, a subtype associated with persistent defibrillation failure and worse long-term survival. Identifying different VF subtypes early may help guide advanced resuscitation strategies in OHCA.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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".