Ventricular fibrillation in myopathic human hearts: mechanistic insights from in vivo global endocardial and epicardial mapping
Bibliographic record
Abstract
Ventricular fibrillation (VF) is an important cause of sudden cardiac death and cardiovascular mortality in patients with cardiomyopathy. Although it was generally believed that chaotic reentrant wavefronts underlie VF in humans, there is emerging evidence of spatiotemporal organization during early VF. The mechanism of this organization of electrical activity in early VF is unknown in myopathic hearts. We studied early VF in vivo, intraoperatively in five cardiomyopathic patients. Simultaneous electrograms were obtained from the epicardium and endocardium in left ventricular cardiomyopathy and from the endocardium in right ventricular myopathy. The Hilbert transform was used to derive the phase of the electrograms. Rotors were identified by isolating phase singularity points. Rotors were present in all of the myopathic hearts studied during VF and cumulatively lasted a mean of 3.2 +/- 2.0 s of the 7.0 +/- 4.0 s of the VF segments analyzed. For each surface mapped, 3.6 +/- 2.9 rotors were identified for the duration mapped. The average number of cycles completed by these rotors was 4.9 +/- 4.9. The longest rotor lasted 10.2 +/- 6.2 rotations and lasted 2.0 +/- 1.2 s. The rotors on the endocardium had a cycle length of 192 +/- 33 ms compared with 220 +/- 15 ms on the epicardium (P=0.08). There is centrifugal activation of electrical activity from these rotors, and they give rise to domains that activate at faster rates with evidence of conduction block at the border with slower domains. These rotors frequently localized to border regions of myocardium with bipolar electrogram amplitude of <0.5 mV. The organization of electrical activity during early VF in myopathic human hearts is characterized by wavefronts emanating from a few rotors.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".