Marijon, Éloi

Abstract Introduction Energy harvesters that convert biomechanical energy into electrical power could be used for implantable devices, providing a near-infinite energy solution. While various energy harvesters with piezoelectric or triboelectric elements have been designed and applied to the cardiac environment, none have been successfully integrated into leadless pacemakers due to their size constraints or insufficient energy generation. Purpose This study aimed to test the performance of a novel self-sustaining leadless pacemaker, which operates on a proprietary inertial piezoelectric energy harvester (PEH) capable of generating the energy required for VVI therapy from the beating of the heart. Method A novel autonomous Leadless Pacing System (ALPS), including a leadless implant, a customized delivery tool catheter, and a home monitor, was developed. The leadless implant was designed to operate on the energy generated by a specially designed PEH that could fit inside the implant. The harvester’s energy was used to charge a small rechargeable backup battery, which provided the energy for a VVI single-chamber therapy. The leadless device and its dedicated delivery tool were then tested in vivo in an ovine model, adhering to the principles of laboratory animal care and with local ethical approval. Results The heart contractility creates harmonic movement in the heart tissue, which is transmitted into the PEH, resulting in the PEH acceleration. The leadless PEH components transform these mechanical forces into electric energy. In pre-clinical testing on an AV block ovine model (n=7), the device was able to pace the animals for 3 months, at 100% pacing, with an average pacing capture threshold of 0.9 (+/-0.5)V, with a pulse width of 0.366 msec, an average impedance of 570 (+/- 115) Ohm, and daily communication with the home monitor device. Conclusion This work demonstrates that a novel leadless pacemaker that utilizes a piezoelectric element to harvest the heart's mechanical energy to generate electrical energy successfully sustains VVI therapy. This approach is able to produce enough energy to maintain device longevity and support additional functionality, such as daily wireless communication with a home monitor, overcoming major limitations of leadless cardiac devices.

Abstract Background and Aims Stroke and systemic embolism are recognized but poorly characterized complications of atrial fibrillation (AF) and left atrial flutter (AFL) catheter ablation. Their incidence, outcomes, and procedural associations remain insufficiently defined. Methods Retrospective global registry was initiated by the European Heart Rhythm Association Scientific Committee. A secure database captured data from ablation centres worldwide on general AF and left AFL ablation activity, as well as detailed information on patients with symptomatic embolic events between 2017 and 2024. Results Overall, 204 centres reported 335 743 ablation procedures and 550 embolic events (incidence 0.16%). Centre-level rate ranged from 0% to 3.1%. Most events were cerebral (94%), followed by peripheral (5%), and combined (1%). Coronary air embolism accounted for 62% of all peripheral events. Intraprocedural events occurred in 93 patients (17%), within 72 h in 357 (78%) and beyond 72 h in 100 (22%); 128 cases (23%) were diagnosed after hospital discharge. Nonparoxysmal AF (0.23% vs 0.15%; P < .001), centre experience, and ablation energy source (radiofrequency, 0.16%; cryoballoon, 0.16%; pulsed field ablation, 0.25%; laserballoon, 0.88%; P < .001) were associated with embolic risk. Median NIHSS score after stroke was 4 (interquartile range, 2–9). Three-month follow-up was available for 518 patients with embolism (95%): 181 (35%) had sequelae and 16 (3%) died. Conclusions Symptomatic embolic events are infrequent but associated with significant morbidity and mortality. Most events occur early, though a substantial proportion arise later. Higher event rates were observed with laser and possibly with pulsed field ablation. A greater centre experience was associated with a lower embolism incidence.

Abstract Intro Energy harvesters that convert biomechanical energy into electrical power could be used for implantable devices, providing a near infinite energy solution. While various energy harvesters with piezoelectric or triboelectric elements have been designed and applied to the cardiac environment, none have been successfully integrated into leadless pacemakers due to their size constraints or insufficient energy generation. Purpose This study aimed to develop a proprietary inertial piezoelectric energy harvester (PEH) capable of generating the energy required for a self-sustaining leadless pacemaker from the beating of the heart. Method Human heart dynamics were tested using ultra-fast MRI scans of 20 patients, which were analyzed for displacement of the right ventricular (RV) apex, mid- to low septum, and the right atrial (RA) walls. The data was used to design the PEH, which was evaluated in thirteen (13) male swine. In addition, epicardial MEMS-based sensors recorded the acceleration, angular positions, and gravity in 3 directions. The sensors were placed at the apex of the RV, LV Apex, LV free wall, and the RA using adhesive means. The data collected from the animals was used to calculate the power produced by the PEH in the different regions of interests and to create a bench model to optimize the PEH design further. The PEH was then tested in-vivo in an ovine model. Results The heart contractility creates harmonic acceleration in the heart tissue, transmitting this vibration into the PEH, resulting in the harvester acceleration of 0.75 g (±0.25g). When the PEH is subject to vibrations, the PEH oscillates using kinetic forces exerted on the piezoelectric beam through a proof mass, transforming these mechanical forces into electric energy. The electrical energy produced using this PEH is 6µW (± 2µW), which is sufficient to power a leadless pacemaker, providing pacing therapy of 100% pacing, at 60 BPM, with heart impedance of 600 (±200), and a pacing voltage reaching 2V, with sufficient excess energy to maintain charge of a secondary battery used for communication and advanced pacemaker functions. This was then tested in a pre-clinical setup, using an ovine model (results to be presented in the future). Conclusion This work demonstrates that a proprietary inertial PEH can use the contraction energy of the heart to generate electrical energy. The design of the PEH was based on the analysis of human heart kinetics using MRI scans and in-vivo recordings from pigs’ hearts. This design of an effective energy harvester can produce enough energy to power a leadless pacemaker. The design can fit in a small capsule that can be used in a leadless pacemaker that will be implanted in the RV providing sensing and pacing as well as daily communication enabling advanced pacemaker functions. The PEH is currently being tested in an ovine model, demonstrating its safety and performance.

BACKGROUND: MODULAR antitachycardia pacing (ATP), a multicenter, international trial, assesses a modular cardiac rhythm management system: a subcutaneous implantable cardioverter defibrillator in wireless communication with a leadless pacemaker (LP) capable of pace-terminating ventricular tachycardia. METHODS: Enrolees had one or more clinical risk factors for ventricular tachycardia and did not require chronic pacing. Complications included prespecified major LP system- and procedure-related complications, and any complication related to the LP, subcutaneous implantable cardioverter defibrillator, implantation, or study protocol. Survival analysis was performed to identify complication-free rates, therapy delivery, and all-cause mortality. RESULTS: The 297 patients enrolled had an ejection fraction of 35±13%, 43% secondary prevention indications, and 59% with prior ventricular arrhythmias. Of 286 patients undergoing LP implantation (100% success), 251 patients completed 12-month follow-up. Mortality rate was 6%, with none related to the implant procedure. Median follow-up duration was 23.4 months (interquartile range, 17.9–28.1). The LP major complication-free rate was 97.2%, exceeding the performance goal. The overall LP+ subcutaneous implantable cardioverter defibrillator system-related complication-free rate was 88.5%. Appropriate tachyarrhythmia-therapy (ATP+shock) rates were 14.4%, and appropriate shock rates were 8.5%. Inappropriate total tachyarrhythmia therapy was 9.5% of which 8.5% were shocks. ATP was 67.3% successful in terminating ventricular arrhythmia episodes and accelerated ventricular arrhythmias in 10.1% of episodes. Overall therapy burden (ATP+shock) was 96/100 patient-years, of which 44/100 patient-years was for shock delivery. CONCLUSIONS: One-year outcomes of the first modular pacing-defibrillator system reveal low system and LP complication rates and good ATP efficacy rates, suggesting that the modular cardiac rhythm management is a viable alternative to single-chamber implantable cardioverter defibrillators using low-energy pacing capability without the need for transvenous leads. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov/ ; Unique identifier: NCT04798768.

Abstract Aims Causes of death remain largely unexplored in the atrial fibrillation (AF) population. We aimed to (i) thoroughly assess causes of death in patients with AF, especially those associated with sudden cardiac death (SCD) and (ii) evaluate the potential association between AF and SCD. Methods and results Linked primary and secondary care United Kingdom Clinical Practice Research Datalink dataset comprising 6 529 382 individuals aged ≥18. We identified 214 222 patients with newly diagnosed AF, and an equivalent number of non-AF patients matched for age, sex and primary care practice. The underlying primary cause of death for each patient was assessed in the form of International Classification of Diseases Tenth Revision (ICD-10) codes and also as part of broader disease categories (i.e. ICD-10 chapters). Findings Over a median follow-up of 2.7 (interquartile range: 0.7–6.0) years, 124 781 (58.25%) patients with AF died. Sudden cardiac death occurred in 13 923 patients with AF [6.50% patients with AF vs. 2.01% non-AF patients; odds ratio (OR) = 3.38, 95% confidence interval (CI): 3.27–3.50, P < 0.0001], contributing to 11.05% of all AF mortality. Diseases of the circulatory system, neoplasms and respiratory diseases explained 45% of AF mortality. Sudden cardiac death occurred more frequently in males (OR = 1.87, 95% CI: 1.80–1.93, P < 0.0001), and females with AF died more often of diseases of the circulatory, respiratory, digestive, and genitourinary system and less often of neoplastic disorders. Interpretation Conditions of the circulatory system are the main driver of mortality in the AF population. Females with AF experience higher cardiovascular and respiratory mortality but die less frequently of neoplasms. The risk of SCD is higher in the AF population, occurring more frequently in males.

Abstract Aims To evaluate the association of basic life support with survival after sports-related sudden cardiac arrest (SR-SCA). Methods and results In this systematic review and meta-analysis, a search of several databases from each database inception to 31 July 2021 without language restrictions was conducted. Studies were considered eligible if they evaluated one of three scenarios in patients with SR-SCA: (i) bystander presence, (ii) bystander cardiopulmonary resuscitation (CPR), or (iii) bystander automated external defibrillator (AED) use and provided information on survival. Risk of bias was evaluated using Risk of Bias in Non-randomized Studies of Interventions. The primary outcome was survival at the longest follow up. The meta-analysis was conducted using the random-effects model. The Grading of Recommendations Assessment, Development, and Evaluations (GRADE) approach was used to rate certainty in the evidence. In total, 28 non-randomized studies were included. The meta-analysis showed significant benefit on survival in all three groups: bystander presence [odds ratio (OR) 2.55, 95% confidence interval (CI) 1.48–4.37; I2 = 25%; 9 studies—988 patients], bystander CPR (OR 3.84, 95% CI 2.36–6.25; I2 = 54%; 23 studies—2523 patients), and bystander AED use (OR 5.25, 95% CI 3.58–7.70; I2 = 16%; 19 studies—1227 patients). The GRADE certainty of evidence was judged to be moderate. Conclusion In patients with SR-SCA, bystander presence, bystander CPR, and bystander AED use were significantly associated with survival. These results highlight the importance of witness intervention and encourage countries to develop their first aid training policy and AED installation in sport settings.

Introduction: Conflicting results exist regarding the impact of gender on survival after Sudden Cardiac Arrest (SCA). Hypothesis: Assess association between female gender and survival after SCA Methods: An electronic search of Embase, Ovid MEDLINE In-Process & Non-Indexed Citations and EBM Reviews - Cochrane Register of Controlled Trials, EBM Reviews - Cochrane Database of Systematic Reviews and Google was conducted (January 1948 to January 2014) for studies of any study design and language, examining the gender effect on survival at hospital discharge after a SCA. Two independent reviewers selected studies and extracted data. The inter-rater agreements kappa were measured at the first and second selection steps. Moreover, the pooled OR and 95% CI, concerning women vs. men survival at hospital discharge after an OHCA were calculated with a random effect model. Subgroups analyses were performed, according to the cardiac origin of OHCAs and according to the study quality. Study quality criteria were based on the New Castle Ottawa Scale. Results: After a detailed screening of 556 citations, 12 studies were identified involving 404 621 patients. The inter-rater agreements kappa was high for the 2 study selection steps (0.91 and 1). In most studies, women were older and had less favorable baseline characteristics including a lower prevalence of witnessed-OHCA, OHCA in a public location, bystander cardio-pulmonary resuscitation and shockable rhythms compared to men. However and after adjustment for these differences, women were more likely to survive at hospital discharge (N=12; OR: 1.11 [1.02-1.21]; p=0.013). This result remains in studies analyzing OHCA of presumed cardiac origin (N=7; OR: 1.17 [1.03-1.34]; p=0.017) and in studies of high quality (N=7; OR: 1.11 [1.02-1.21]; p=0.017). Conclusion: Despite less favorable baseline characteristics, women are more likely to survive at hospital discharge after an OHCA. Further studies are needed to explain this paradox.

Abstract Aims While data from randomized trials suggest a declining incidence of sudden cardiac death (SCD) among heart failure patients, the extent to which such a trend is present among patients with cardiac resynchronization therapy (CRT) has not been evaluated. We therefore assessed changes in SCD incidence, and associated factors, in CRT recipients over the last 20 years. Methods and results Literature search from inception to 30 April 2018 for observational and randomized studies involving CRT patients, with or without defibrillator, providing specific cause-of-death data. Sudden cardiac death was the primary endpoint. For each study, rate of SCD per 1000 patient-years of follow-up was calculated. Trend line graphs were subsequently constructed to assess change in SCD rates over time, which were further analysed by device type, patient characteristics, and medical therapy. Fifty-three studies, comprising 22 351 patients with 60 879 patient-years of follow-up and a total of 585 SCD, were included. There was a gradual decrease in SCD rates since the early 2000s in both randomized and observational studies, with rates falling more than four-fold. The rate of decline in SCD was steeper than that of all-cause mortality, and accordingly, the proportion of deaths which were due to SCD declined over the years. The magnitude of absolute decline in SCD was more prominent among CRT-pacemaker (CRT-P) patients compared to those receiving CRT-defibrillator (CRT-D), with the difference in SCD rates between CRT-P and CRT-D decreasing considerably over time. There was a progressive increase in age, use of beta-blockers, and left ventricular ejection fraction, and conversely, a decrease in QRS duration and antiarrhythmic drug use. Conclusion Sudden cardiac death rates have progressively declined in the CRT heart failure population over time, with the difference between CRT-D vs. CRT-P recipients narrowing considerably.