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Background Concomitant epicardial ablation of ventricular tachycardia (VT) remains a clinical challenge in cardiac surgery due to the need for intra-operative mapping. A preoperative patient-tailored epicardial guide could provide an intraoperative ‘blueprint’ of arrhythmogenic target substrate, thereby facilitating the workflow. Thus far, no 3D printing material or technique has fully met the requirements for this application. This study explores the feasibility of high-consistency rubber (HCR) silicone molding to produce low-cost, customized guides for VT scar ablation. Methods An inverted mold was created in Meshmixer using merged LGE–CMR and cardiac CT images of a 61-year-old VT patient, and printed using fused deposition modeling. HCR silicone was milled, sculpted, and trimmed to fit the negative mold. The guide was cured, subjected to autoclaving, and bench-tested on an ex vivo porcine heart model using radiofrequency and cryo-ablation. Various durometers and thicknesses were tested to determine the optimal fit for our application. Results Five surgical guides were made using NuSil ™ MED-4072 and MED-4080 silicone (thickness range: 2.0–3.4 mm). Models with 2.1–3.0 mm thickness and 70 Shore A hardness achieved the best balance between flexibility and rigidity for application on a beating heart. The thinnest model (2.0 mm) was too pliable for stable placement. The guides withstood autoclaving and ablation procedures (radiofrequency; cryo-energy) without deformation or compromising structural integrity. Conclusions The HCR silicone molding technique allows for the production of flexible, cost-effective epicardial guides for VT ablation, minimizing the need for a full electrophysiology team throughout the entire procedure.

PurposeThe purpose of the study was to evaluate the impact of left atrial posterior wall isolation (LAPWI) in addition to pulmonary vein isolation (PVI) vs PVI alone, performed using CB-A, in patients with PAF on a midterm follow-up of 12 months.MethodsEighty consecutive patients indicated to index cryoballoon ablation (CB-A) for the treatment of drug resistant PAF were included. The first 50 (62.5%) underwent PVI only, and the following 30 patients (37.5%) underwent LAPWI + PVI.ResultsAcute isolation was achieved in all PVs in both groups. The LAPW was successfully isolated in 29 out of 30 (97%) patients; in the remaining patient, adjunct radiofrequency ablation was required. The total procedure time and the mean fluoroscopy time were significantly shorter in patients who underwent PV isolation only (p < 0.001).The freedom from atrial fibrillation (AF) at 12 months was not significantly different between the 2 groups (LAPW + PVI = 90% vs PVI = 88%) (log-rank p = 0.816).ConclusionLAPW ablation in addition to PVI by the means of CB-A does not seem to reduce the risk of AF recurrence if compared with the standard PVI on a midterm follow-up of 12 months.

BackgroundCatheter ablation for persistent atrial fibrillation (persAF) is associated with less favorable outcomes than for paroxysmal AF. To improve success rates, left atrial (LA) substrate modification is frequently performed in addition to pulmonary vein isolation (PVI). The purpose of the study was to compare 4 different ablation approaches using radiofrequency catheter ablation (RFCA) or cryoballoon ablation (CB-A) for persAF and to evaluate the respective outcomes on a midterm follow-up of 12 months.MethodsWe did a propensity score–matched comparison of 30 patients undergoing PVI + LA posterior wall isolation (LAPWI) with CB-A, 30 patients who underwent PVI + linear ablation (roof and mitral lines) using RFCA, 60 patients with PVI alone using CB-A, and 60 patients who had PVI alone using RFCA. The endpoint was recurrence of documented atrial tachyarrhythmias (ATas) > 30 s at 1-year follow-up.ResultsAfter 12 months, freedom from ATas after a single procedure was 83.3% in the PVI + LAPWI group, 46.7% in the PVI + linear ablation group, 58.3% in the PVI-alone CB-A group, and 61.6% PVI-alone RFCA (p = 0.03). Moreover, freedom from ATas was significantly higher comparing the PVI + LAPWI group with each of the other groups.ConclusionsIn this propensity-matched comparison of strategies for persAF, LAPW ablation in addition to PVI with CB-A seems to improve 1-year outcome in comparison to PVI + linear ablation using RFCA and to PVI alone using RFCA or CB-A. Randomized comparisons are eagerly awaited.

PurposeThe purpose of this study was to evaluate the safety and feasibility of the new high-resolution mapping algorithm SuperMap (Acutus Medical, CA, USA) in identifying and guiding ablation in the setting of regular atrial tachycardias following index atrial fibrillation (AF) ablation.MethodsSeven consecutive patients who underwent a radiofrequency catheter ablation guided by the novel noncontact charge density (CD) SuperMap for atrial tachycardia were prospectively enrolled in our study.ResultsArrhythmogenic substrate was identified in all seven patients. Mean number of EGM per map was 5859.7 ± 4348.5 points. Three patients (43%) exhibited focal tachycardia mechanisms in the left atrium, alternating from anteroseptal right superior pulmonary vein (RSPV), posterior in proximity of left inferior pulmonary vein (LIPV), and interarial septum in proximity of fossa ovalis, respectively. Four patients exhibited macroreentrant mechanism. In 3 of these patients, SuperMap detected mitral isthmus-dependent flutters with tachycardia cycle lengths of 240, 270 and 420 ms, respectively. In one patient, the mechanism was a macroreentrant tachycardia with the critical isthmus located between the crista terminalis and atriotomy. The mean ablation time (min) was 18.2 ± 12.5 and the mean procedural duration time was 56.4 ± 12.1 min. No minor or major complications occurred.ConclusionThe novel high-resolution mapping algorithm SuperMap proved to be safe, fast, and feasible in identifying and guiding ablation in the setting of regular atrial tachycardias following index AF ablation.

Aims To evaluate the clinical outcome in patients undergoing repeat procedures for recurrent persistent atrial fibrillation following an index cryoballoon (CB‐A) pulmonary vein isolation ablation on a mid‐term follow‐up of 12 months. Methods In this propensity score‐matched comparison, 50 patients undergoing left atrial posterior wall isolation (LAPWI) with the CB‐A were matched to 50 patients treated with additional linear ablation using radiofrequency catheter ablation (RFCA). Results Meantime to repeat the procedure was 9.74 ± 4.36 months. At 12 months follow‐up freedom from atrial tachyarrhythmias (ATas) was achieved in 82% of patients in the LAPWI group and in 62% of patients in the linear ablation group (P = .03). Regression analysis demonstrated that relapses during the blanking period and LA dimensions were independent predictors of ATas recurrences following the repeat procedure. Conclusion LAPWI using CB‐A is associated with a significantly higher freedom from atrial arrhythmias when compared with the RFCA mediated left atrial linear lesions on a mid‐term follow‐up of 12 months in patients with persAF undergoing a redo procedure. LAPWI using CB‐A is associated with a significantly higher freedom from atrial arrhythmias when compared with the RFCA mediated left atrial linear lesions on a mid‐term follow‐up of 12 months in patients with persAF undergoing a redo procedure.

Patient-specific three-dimensional (3D) printed models have been increasingly used in many medical fields, including cardiac surgery for which they are used as planning and communication tools. To locate and plan the correct region of interest for the bypass placement during coronary artery bypass graft (CABG) surgery, cardiac surgeons can pre-operatively rely on different medical images. This article aims to present a workflow for the production of a patient-specific 3D-printed surgical guide, from data acquisition and image segmentation to final prototyping. The aim of this surgical guide is to help visualize the region of interest for bypass placement during the operation, through the use of dedicated surgical holes. The results showed the feasibility of this surgical guide in terms of design and fitting to the phantom. Further studies are needed to assess material biocompatibility and technical properties.

Background: In the field of medicine, photogrammetry has played for long time a marginal role due to the significant amount of work required that made it impractical for an extended medical use. Developments in digital photogrammetry occurred in the recent years, that have steadily increased the interest and application of this technique. The present study aims to compare photogrammetry reconstruction of heart with computed tomography (CT) as a reference. Methods: The photogrammetric reconstructions of digital images from ECG imaging derived images were performed. In particular, the ventricles of 15 patients with Brugada syndrome were reconstructed by using the free Zephyr Lite software. In order to evaluate the accuracy of the technique, measurements on the reconstructions were compared to patient-specific CT scan imported in ECG imaging software UZBCIT. Result: The results showed that digital photogrammetry in the context of ventricle reconstruction is feasible. The photogrammetric derived measurements of ventricles were not statistically different from CT scan measurements. Furthermore, the analysis showed high correlation of photogrammetry reconstructions with CT scan and a correlation coefficient close to 1. Conclusion: It is possible to reproduce digital objects by photogrammetry if the process described in this study is performed. The reconstruction of the ventricles from CT scan was very close to the values of the respective photogrammetric reconstruction.

Electrical isolation of pulmonary veins (PVI) is the cornerstone of invasive treatment of atrial fibrillation (AF). However, arrhythmia-free survival of a PVI only approach is suboptimal in patients with persistent and long-term persistent AF. Hybrid AF ablation has been developed with the aim of combining the advantages of a thoracoscopic surgical ablation (direct visualization of anatomical structures to be spared and the possibility to perform epicardial lesions) and endocardial ablation (possibility to check line block, confirm PVI, and possibility to perform cavotricuspid isthmus ablation). Patient selection is of utmost importance. In persistent and long-term persistent AF, hybrid AF ablation demonstrated promising results in terms of AF free survival. It has been associated with a relatively low complication rate if performed in centers with expertise in hybrid procedures and experience with both surgical and endocardial ablation. Different techniques have been described, with different approaches and lesion sets. The aim of this review is to provide a state-of-the-art overview of hybrid AF ablation.

To date, studies assessing the safety profile of 3D printing materials for application in cardiac ablation are sparse. Our aim is to evaluate the safety and feasibility of two biocompatible 3D printing materials, investigating their potential use for intra-procedural guides to navigate surgical cardiac arrhythmia ablation. Herein, we 3D printed various prototypes in varying thicknesses (0.8 mm–3 mm) using a resin (MED625FLX) and a thermoplastic polyurethane elastomer (TPU95A). Geometrical testing was performed to assess the material properties pre- and post-sterilization. Furthermore, we investigated the thermal propagation behavior beneath the 3D printing materials during cryo-energy and radiofrequency ablation using an in vitro wet-lab setup. Moreover, electron microscopy and Raman spectroscopy were performed on biological tissue that had been exposed to the 3D printing materials to assess microparticle release. Post-sterilization assessments revealed that MED625FLX at thicknesses of 1 mm, 2.5 mm, and 3 mm, along with TPU95A at 1 mm and 2.5 mm, maintained geometrical integrity. Thermal analysis revealed that material type, energy source, and their factorial combination with distance from the energy source significantly influenced the temperatures beneath the 3D-printed material. Electron microscopy revealed traces of nitrogen and sulfur underneath the MED625FLX prints (1 mm, 2.5 mm) after cryo-ablation exposure. The other samples were uncontaminated. While Raman spectroscopy did not detect material release, further research is warranted to better understand these findings for application in clinical settings.

The article “Novel noncontact charge density map in the setting of post-atrial fibrillation atrial tachycardias.