A Novel Hybrid Transcatheter Ablation System That Combines Radiofrequency and Cryoenergy
Bibliographic record
Abstract
INTRODUCTION: Radiofrequency (RF) and cryoenergy are largely considered independent modalities for the transcatheter ablation of cardiac arrhythmias. There are numerous theoretical advantages to engineering a system capable of delivering both energy forms. METHODS AND RESULTS: We designed a hybrid steerable catheter capable of delivering RF and cryoenergy independently, sequentially, and simultaneously. The novel catheter system was tested pre-clinically by creating a total of 180 ablation lesions in 20 mongrel dogs. Right atrial and right and left ventricular sites were preselected by a randomized factorial design devised to compare sequential and simultaneous RF and cryoenergy applications to standard RF, irrigated RF, and standard cryoablation. A steerable 4-mm electrode-tip hybrid catheter ("Fire and Ice") was created by modifying a 7 F cryocatheter (Freezor, CryoCath Technologies, Montreal, Canada). RF energy was injected via a copper wire, thermocouples were isolated to reduce RF interference, and 100 KHz band pass filters and RF chokes were added. Sequential low-dose RF (20 W, 60 seconds) preceding or following cryoablation resulted in larger lesions (P = 0.0010). The addition of RF energy did, however, produce more thrombus than cryoenergy alone, with clot detected on 82.4% versus 12.1% of ablation lesions, P < 0.0001. Simultaneously applying the two energy modalities (45 W, 10 or 30 degrees C, 60 seconds) created more voluminous lesions than standard RF ablation (median 288.1 vs 126.1 mm(3), P = 0.0333) of similar dimension to irrigated RF ablation. CONCLUSION: A versatile catheter system was fashioned capable of creating standard cryoablation lesions, standard RF lesions, and simultaneous lesions of similar dimension to irrigated RF.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.000 | 0.000 |
| 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".