Background The use of intra-cardiac electrograms to guide atrial fibrillation (AF) ablation has yielded conflicting results. We evaluated an electrogram marker of AF drivers: the clustering of electrograms exhibiting spatio-temporal dispersion — regardless of whether such electrograms were fractionated or not. Objective To evaluate the usefulness of spatio-temporal dispersion, a visually recognizable electric footprint of AF drivers, for the ablation of all forms of AF. Methods We prospectively enrolled 105 patients admitted for AF ablation. AF was sequentially mapped in both atria with a 20-pole PentaRay catheter. We tagged and ablated only regions displaying electrogram dispersion during AF. Results were compared to a validation set in which a conventional ablation approach was used (pulmonary vein isolation/stepwise approach). To establish the mechanism underlying spatio-temporal dispersion of AF electrograms, we conducted realistic numerical simulations of AF drivers in a 2-dimensional model and optical mapping of ovine atrial scar-related AF. Results Ablation at dispersion areas terminated AF in 95%. After ablation of 17±10% of the left atrial surface and 18 months of follow-up, the atrial arrhythmia recurrence rate was 15% after 1.4±0.5 procedure/patient vs 41% in the validation set after 1.5±0.5 procedure/patient (arrhythmia free-survival rates: 85% vs 59%, log rank P<0.001). In comparison with the validation set, radiofrequency times (49 ± 21 minutes vs 85 ± 34.5 minutes, p=0.001) and procedure times (168 ± 42 minutes vs. 230 ± 67 minutes, p<.0001) were shorter. In simulations and optical mapping experiments, virtual PentaRay recordings demonstrated that electrogram dispersion is mostly recorded in the vicinity of a driver. Conclusions The clustering of intra-cardiac electrograms exhibiting spatio-temporal dispersion is indicative of AF drivers. Their ablation allows for a non-extensive and patient-tailored approach to AF ablation. Clinical trial.gov number: NCT02093949

Objectives To evaluate the clinical and visual outcomes following intensive medical therapy for keratomalacia in dogs. Materials and Methods Medical records were screened to identify dogs with corneal ulcers and keratomalacia. All patients were given the same topical treatment protocol with frequent administrations of tobramycin in combination with equine serum. Surgical treatment during the first 15 days of follow‐up was considered as medical treatment failure. Results We report on 57 ulcers with keratomalacia from 53 dogs. Medical treatment was successful in 31 of 57 ulcers with a median healing time of 5 days (range 2 to 15 days). At 60 days after epithelialisation, 14/15 medically‐treated eyes were visual. In one case, corneal perforation was observed 1 month after healing and required surgical stabilisation. Clinical Significance Intensive medical therapy has the potential to achieve healing of some ulcers with keratomalacia. Surgical stabilisation in response to progression of stromal loss was required in less than half of the cases.

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CFAE-guided ablation leads to a large decrease in PV frequency of activation, preceding AF termination. A PV modulation approach, rather than complete PVI, may be preferable for persistent AF.

Introduction: Multi-electrode electrogram temporal activation and fractionation have been used to localize atrial fibrillation (AF) drivers. Yet, the feasibility of a simplified “online” analysis and its usefulness to ablate AF remain to be investigated. Hypothesis: Evaluating a simplified “online” electrogram analysis approach designed to localize and ablate AF drivers. Methods: 105 patients undergoing AF ablation (77% with persistent AF, 3 centres) were prospectively enrolled. AF was first mapped in both atria with the 20-pole contact electrode catheter PentaRay® (Biosense Webster, Inc.) in order to identify regions with a temporal activation pattern compatible with the presence of rapidly rotating rotors. Specifically, regions with consecutive activations spanning the majority of the AF cycle length (including examples of rapid and continuously fractionated electrograms) were visually selected (“hot zone”).The endpoints were AF termination acutely, and freedom from long-term AF (single procedure). Off-line, electrogram cycle length values were compared between “hot” and “non-hot” regions and a numerical simulation of PentaRay-enabled unipolar recordings of a stable rotor driving AF was conducted Results: Visually selected “hot” regions located mostly in the left atrium (6.5 ±4.2/patient; ~70% of ”hot” regions). “Hot” regions were activated at a significantly shorter cycle length than “non-hot” regions (171.8 ± 4.8 vs. 193.0 ± 6.3 ms, p=0.01, N=20). 95.6% of the “hot regions” were automatically labelled CFAEs (automated analysis, Carto). However, 4.5±3.4 distinct CFAEs regions/patient were also labelled in “non-hot” regions. Ablation at “hot” regions terminated AF in 99/104 patients (95.2%), 46 [21-72] min after the 1st radiofrequency application within 20 [10-37] min of RF. Also, numerical simulations show that a simplified PentaRay®-enabled activation analysis is sufficient to distinguish rotor and non-rotor regions. After 9+3 [6-11], months of median [Q1-Q3] follow-up, 87 % were free from AF after 1 procedure and 53 % still under antiarrhythmic drugs. Conclusions: With this simplified “online” analysis, we could successfully localize rotor regions and perform efficient AF ablation. Clinical trial.gov: NCT02093949