Background: The analysis of the wave-front activation patterns is crucial for the comprehension and treatment of ventricular tachycardia (VT). The ventricular electrograms duration map (VEDUM) is a potential method to identify areas (VEDUM area) with slow and inhomogeneous activation. There is no available data on the characteristics and the arrhythmogenic role of VEDUM areas identified during sinus/paced rhythm. Methods: Patients referred for VT ablation were enrolled at 3 different centers. VEDUM maps during sinus/paced rhythm as well as substrate and functional maps were created; activation mapping was performed for all hemodynamically tolerated VT. Results: Thirty-two patients (mean age:70.1±9.4 years; males 93.8%) were enrolled. The VEDUM approach was achieved in all patients and the mean size of the VEDUM area was 12.1±6.9 cm 2 (interquartile range, 7.8–14.9 cm 2 ). A significative difference was observed between the electrogram duration in the VEDUM area and the normal tissue (163.7 ms [interquartile range, 142.3–199.2 ms]; versus 65.5 ms [interquartile range, 59.5–76.2 ms]; P <0.001). The VEDUM area was visualized in a dense scar (<0.5 mV) in 19 (59.4%) patients. A deceleration zone and late potentials were recorded inside the VEDUM area in 56.3% and 81.3%, respectively. When a complete VT activation mapping was available, the isthmus projected in the VEDUM area in 93.5% of patients; 8 of them had multiple VTs mapped and in the 87.5% all VT isthmuses were included in the VEDUM area. Conclusions: VEDUM maps allow the identification of discrete areas of inhomogeneous and slow conduction. They represent a potential target for VT ablation, including patients with multiple morphologies.

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Background Pulsed Field Ablation (PFA) is a new and promising non-thermal ablation modality for Pulmonary Vein Isolation (PVI) for the treatment of patients with Atrial Fibrillation (AF). It preferentially ablates myocardial tissue via electroporation leading to minimal effects on surrounding structures. We sought to evaluate safety and efficacy of PFA in our single center experience. Methods PFA was performed at optimized bipolar biphasic waveform using Farapulse system. A protocol of 8 pulses per vein, 4 in the basket configuration and 4 in the flower configuration was followed. The procedure was performed under general anesthesia. Fluoroscopy was used to guide single transseptal puncture. 1 mg of atropine was administered before starting applications. One third of patients underwent CTI ablation using radiofrequency during the same procedure. In one patient we mapped the left atrium before and after ablation using a high-density mapping catheter. Results We prospectively enrolled 21 patients (76% men, age 58,6 ± 9) who underwent PVI using PFA from July to September 2022 for the treatment of Paroxysmal AF (81%) or Persistent AF (19%). Acute pulmonary veins isolation was achieved in the totality of patients. Median skin-to-skin procedure time and catheter dwell time were 56 minutes and 29 minutes respectively. Median fluoroscopy time was 12 minutes. The average number of total applications was 34 ± 4. No adverse events were observed. After a median follow-up of 77 days, we observed early AF recurrence in two patients. Conclusion Preliminary results of our singe center experience confirm that PFA is a safe and effective ablation modality. Pulmonary vein isolation can be achieved very rapidly with short procedural time, catheter dwell time and fluoroscopy time. Further studies are needed to assess durability of the technique.