Multi-modal physiological parameter for mapping ablation lesions
Notice bibliographique
Résumé
Abstract Funding Acknowledgements Type of funding sources: None. Background In addition to variety of force time indices, electrophysiologist use peak to peak voltage (Vpp) and or S wave on unipolar electrogram to assess RF lesions they deliver. This strategy ignores cardiac conduction speed, direction, and wave curvature, all of which are affected by delivered lesion. Electrode array catheters such as the Advisor HD Grid allow individual cardiac wavefronts from sites to be characterized simultaneously in two dimensions from which vectorcardiograms can be derived. This underappreciated attribute of electrograms when integrated into activation mapping may provide new insights into the electrophysiologic state of tissue including wavefront amplitude, direction and velocity. Objective We tested the hypothesis that intracardiac vectorcardiogram loops contain aspects of properties that may better detect lesions compared to Vpp reduction and that a novel multi-modal approach will provide additional insights on wavefront interaction with substrate. Methods In 5 ex-vivo Langendorff perfused swine hearts, 56-pole (7 x 8 configuration) electrode arrays were sutured to the anterior epicardial left ventricle. Unipolar electrograms were acquired with UHN mapping system during programmed stimulation from all cardinal directions before and after creating RF ablation lesions. Vector loop maps were derived from orthogonal bipole pairs to study wavefront organization and voltage. Isochrone maps were generated from unipolar local activation times. Vector loop eccentricity was defined for each 4-electrode group as a function of loop’s major and minor axis lengths. Low values denote less eccentricity (more circular). Results An illustrative example of vector, loop and isochrone maps before and after ablation is shown in figures 1 and 2. Pre-ablation conditions show activation from a point stimulation on the left side with slender vector loops indicative of a relatively homogeneous linear conduction. In contrast, post-ablation vector loops are much less eccentric near the ablated area and smaller reflecting attenuated amplitude. Interestingly, near border zone locations large round loops are observed, suggesting curved or nonlinear wave propagation. Figure 2 shows that vector loops recorded from scar areas were diminished in size following ablation with a mean Vpp of 3.76 vs 2.18mV (p=0.0001) and exhibited less mean eccentricity, 0.925 vs 0.848 (p<0.0001), with more round loops (eccentricity < 0.7) found after ablation (12% of sites vs 4% pre-ablation, p < 0.0001). Conclusions Significant changes in loop characteristics were observed even when ablation induced voltage attenuation was minimal. This suggests that vectorial loop eccentricity may provide information in addition to omnipolar Vpp. Wavefront propagation disruption near ablation border zones is thus potentially valuable to detect lesion gaps. This information along with wave amplitude and direction can now be integrated into a novel multi-modal map.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».