Clinical experience with a diaphragmatic electromyographic-guided approach to monitor phrenic nerve integrity during cryoballoon-based atrial fibrillation ablation
Bibliographic record
Abstract
Background: Despite standard monitoring, phrenic nerve palsy (PNP) remains the most frequent complication associated with cryoballoon ablation for AF, with a recent metanalysis showing an incidence of 6.38%. We sought to characterize our experience using the only method that monitor the electrical activity of the phrenic nerve, the Compound Motor Action Potential or CMAP monitoring of the right hemi-diaphragm for the prevention of PNP. Methods: The records of consecutive patients who underwent cryoballoon-based pulmonary vein isolation between October 2010 and January 2013 were studied. In addition to standard monitoring (abdominal palpation during right phrenic nerve pacing from the superior vena cava at 60 bpm; 20 mAmp; 2 ms), all patients underwent diaphragmatic EMG monitoring using surface electrodes during ablation of the right-sided PVs. Cryoablation was halted if a 30% decrease in the amplitude of the diaphragmatic compound motor action potential (CMAP). Both size and generation of cryoballoon were used, Arctic Front™ Medtronic CryoCath LP until August 2012 and Arctic Front Advance™, Medtronic CryoCath LP since September 2012. Results: One hundred and thirty patients [98 males; 58 years±10] were included. Analysis of CMAP potential during right-sided ablation indicated a significant decrease (30% decrease in amplitude) in 35 patients (27%) and the diaphragmatic motion decreased in 22 of those patients (63%). Signal decrease occurred during RSPV isolation in 28 cases, RMPV in 2 cases and RIPV in 5 cases. A 23mm cryoballoon was used in 63% of cases of CMAP amplitude decrease. In all cases, decrease in CMAP amplitude preceded transient decrease of diaphragmatic motion. There was only 3 case of persistent phrenic nerve palsy, and 2 without recovering within 3 months and one recovered within 5 months. All the veins were isolated despite the shortened application (35/35 veins). When these patients needed a second procedure, only 3/35 (9%) of the right-sided veins were reconnected. Conclusion: Electromyographic phrenic nerve integrity monitoring using the diaphragmatic CMAP is feasible, reliable, and easy to perform. Compared to standard monitoring, diaphragmatic CMAP potentials lowers the incidence of persistent phrenic nerve palsy with 3 case (2%) in this study. This method is the only one which can predict the phrenic nerve palsy before it's happened.
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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 | 0.004 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".