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Objective. Cardiac arrhythmias are a leading cause of mortality worldwide. Wearable devices based on photoplethysmography give the opportunity to screen large populations, hence allowing for an earlier detection of pathological rhythms that might reduce the risks of complications and medical costs. While most of beat detection algorithms have been evaluated on normal sinus rhythm or atrial fibrillation recordings, the performance of these algorithms in patients with other cardiac arrhythmias, such as ventricular tachycardia or bigeminy, remain unknown to date. Approach.  The PPG-beats open-source framework, developed by Charlton and colleagues, evaluates the performance of the beat detectors named QPPG , MSPTD and ABD among others. We applied the PPG-beats framework on two newly acquired datasets, one containing seven different types of cardiac arrhythmia in hospital settings, and another dataset including two cardiac arrhythmias in ambulatory settings. Main Results.  In a clinical setting, the QPPG beat detector performed best on atrial fibrillation (with a median F 1 score of 94.4%), atrial flutter (95.2%), atrial tachycardia (87.0%), sinus rhythm (97.7%), ventricular tachycardia (83.9%) and was ranked 2nd for bigeminy (75.7%) behind ABD detector (76.1%). In an ambulatory setting, the MSPTD beat detector performed best on normal sinus rhythm (94.6%), and the QPPG detector on atrial fibrillation (91.6%) and bigeminy (80.0%). Significance.  Overall, the PPG beat detectors QPPG , MSPTD and ABD consistently achieved higher performances than other detectors. However, the detection of beats from wrist-PPG signals is compromised in presence of bigeminy or ventricular tachycardia., (Creative Commons Attribution license.)

Aims: Stereotactic arrhythmia radioablation (STAR) has been recently introduced for the management of therapy-refractory ventricular tachycardia (VT). VT recurrences have been reported after STAR but the mechanisms remain largely unknown. We analysed recurrences in our patients after STAR., Methods and Results: From 09.2017 to 01.2020, 20 patients (68 ± 8 y, LVEF 37 ± 15%) suffering from refractory VT were enrolled, 16/20 with a history of at least one electrical storm. Before STAR, an invasive electroanatomical mapping (Carto3) of the VT substrate was performed. A mean dose of 23 ± 2 Gy was delivered to the planning target volume (PTV). The median ablation volume was 26 mL (range 14-115) and involved the interventricular septum in 75% of patients. During the first 6 months after STAR, VT burden decreased by 92% (median value, from 108 to 10 VT/semester). After a median follow-up of 25 months, 12/20 (60%) developed a recurrence and underwent a redo ablation. VT recurrence was located in the proximity of the treated substrate in nine cases, remote from the PTV in three cases and involved a larger substrate over ≥3 LV segments in two cases. No recurrences occurred inside the PTV. Voltage measurements showed a significant decrease in both bipolar and unipolar signal amplitude after STAR., Conclusion: STAR is a new tool available for the treatment of VT, allowing for a significant reduction of VT burden. VT recurrences are common during follow-up, but no recurrences were observed inside the PTV. Local efficacy was supported by a significant decrease in both bipolar and unipolar signal amplitude., Competing Interests: Conflict of interest: CHS received educational grants through her institution from Biosense Webster, Microport and Abbott; and speaker fees from Daiichi Sankyo. TR has received research grants from the Swiss National Science Foundation, the Swiss Heart Foundation and the sitem insel support fund, all for work outside the submitted study. Dr. Reichlin has received research support for investigator initiated projects from Biosense Webster, Biotronik, Boston Scientific and Medtronic, all for work outside the submitted study. He has received speaker/consulting honoraria or travel support from Abbott/SJM, Bayer, Biosense Webster, Biotronik, Boston Scientific, Daiichi Sankyo, Farapulse, Medtronic and Pfizer-BMS, all for work outside the submitted study. He has received support for his institution’s fellowship programme from Abbott/SJM, Biosense Webster, Biotronik, Boston Scientific and Medtronic for work outside the submitted study. BK received educational support from Medtronic, Abbott and Biotronik. AMS received educational grants through his institution from Abbott, Bayer Healthcare, Biosense Webster, Biotronik, Boston Scientific, BMS/Pfizer, and Medtronic; and speaker/advisory board/consulting fees from Abbott, Bayer Healthcare, Daiichi Sankyo, Medtronic, Novartis and Pfizer. EP received Educational Grants through his institution from Medtronic, and research grants from the Swiss National Science Foundation and from the European Community (H2020). All remaining authors have declared no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Fracture fixation in weak bone is still a clinical challenge. Screw augmentation was shown to successfully increase their primary stability. The currently used calcium phosphate or polymeric bone cements, however, present important drawbacks such as induced toxicity and/or impaired bone neo-formation. A new approach to enhance bone screw primary stability without affecting bone formation is the use of non-setting, calcium phosphate loaded soft materials as the augmentation material., Methods: Two types of biomaterials (non-crosslinked hyaluronic acid as viscous fluid and agar as hydrogel) were loaded with 40 wt/vol% of hydroxyapatite particles and characterized. The screw augmentation effect of all materials was evaluated through pull-out tests in bovine cancellous bone and compared to the non-augmented situation (control). The bone mineral density of each test sample was measured with μCT scans and was used to normalize the pull-out strength., Findings: Both materials loaded with hydroxyapatite increased the normalized pull-out strength of the screws compared to control samples and particle-free materials. This counter-intuitive augmentation effect increased with decreasing bone mineral density and was independent from the type of the soft materials used., Interpretation: We were able to demonstrate that non-setting, injectable biomaterials loaded with ceramic particles can significantly enhance the primary stability of bone screws. This material combination opens the unique possibility to achieve a screw augmentation effect without impairing or even potentially favoring the bone formation in proximity to the screw. This effect would be particularly advantageous for the treatment of osteoporotic bone fractures requiring a stabilization with bone screws., (Copyright © 2018 Elsevier Ltd. All rights reserved.)