BACKGROUND: Complications associated with transvenous pacemakers, specifically those involving the lead or subcutaneous pocket, may be avoided with leadless pacemakers (LPs). The safety and efficacy of single-chamber right ventricular LPs have been demonstrated, but their right atrium (RA) use poses new design constraints. OBJECTIVES: The purpose of this study was to evaluate the implant success, electrical performance, and safety of a novel RA LP design in benchtop and preclinical studies. METHODS: A new LP was designed with a dual-helix fixation mechanism specific to the RA anatomy. A 12-week preclinical ovine study was conducted to evaluate implant success, electrical performance, mechanical stability, and safety in vivo, with supporting benchtop measurements to quantify the mechanical forces needed for device retrieval and dislodgment. RESULTS: LPs were successfully implanted in all 10 ovine subjects with no complications. The pacing capture threshold improved significantly over time from implant to week 12 (1.1 ± 0.7 V vs 0.4 ± 0.2 V, P = .008). Sensing amplitudes and pacing impedances were stable from implant to week 12 (4.8 ± 1.8 mV vs 6.0 ± 1.9 mV, P = .160; and 393 ± 77 Ω vs 398 ± 65 Ω, P = .922, respectively). Gross pathology and microscopic histology revealed no adverse interactions and no evidence of device dislodgment or clinically significant myocardial perforation. Benchtop ex vivo porcine atrial tissue measurements revealed greater pull forces required to dislodge the LP vs transvenous active fixation lead (0.42 ± 0.18 lbf vs 0.29 ± 0.08 lbf, P = .020), and greater rotational forces required for deliberate extraction (0.28 ± 0.04 lbf vs 0.14 ± 0.07 lbf, P <.001). CONCLUSION: The novel atrial LP demonstrated successful implantation, with acceptable electrical performance, mechanical stability, and safety in a 12-week preclinical study.

• MeSH
• Equipment Design MeSH
• Cardiac Pacing, Artificial MeSH
• Pacemaker, Artificial * MeSH
• Humans MeSH
• Lipopolysaccharides * MeSH
• Sheep MeSH
• Swine MeSH
• Prostheses and Implants MeSH
• Heart Atria MeSH
• Treatment Outcome MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

In a pivotal trial (NCT05252702), the AVEIR DR (Abbott) leadless pacemaker system was found to be safe and effective in delivering DDDR synchronous atrial and ventricular pacing. This dual-chamber system employs 2 leadless pacemakers with implant-to-implant communication. Although implantation of the ventricular device as a single-chamber pacemaker has been well described, there are additional considerations surrounding the dual-chamber implantation procedure. Herein, we review the dual-chamber leadless pacemaker implantation workflow while providing guidance to optimize safe and effective implantation procedures.

• MeSH
• Equipment Design * MeSH
• Prosthesis Implantation methods   instrumentation   MeSH
• Cardiac Pacing, Artificial methods   MeSH
• Pacemaker, Artificial * MeSH
• Humans MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

• Publication type
• Case Reports MeSH

AIMS: A dual-chamber leadless pacemaker (LP) system that employs distinct atrial and ventricular LP devices (ALP, VLP) has been introduced to clinical practice. Proprietary, low-energy, implant-to-implant (i2i) communication at each beat enables the devices to maintain synchronous atrioventricular sensing and pacing. We evaluated device longevities and contributing factors, such as i2i communication. METHODS AND RESULTS: Patients meeting dual-chamber pacing indications received the dual-chamber LP system as part of a prospective, multi-centre, international clinical trial (Aveir DR i2i Study, NCT05252702). Programming and diagnostics were interrogated from all de novo, non-revised, dual-chamber programmed devices at 12 months post-implant. This analysis included 302 patients (65% male; age 70 ± 13 years; weight 80 ± 19 kg; intrinsic heart rate 55 ± 7 bpm; 58% sinus node dysfunction, 27% atrioventricular block). At 12 months, devices were programmed to dual-chamber pacing (DDD(R) or DDI(R)) at a median 60 bpm rate, median 1.25 V pulse amplitude in ALP and 1.5 V in VLP, median 0.4 ms pulse width, and median i2i signal setting level 5 out of 7. Median ALP and VLP remaining battery longevities at 12 months were 4.3 and 9.1 years, with median total ALP and VLP longevities of 5.3 and 9.9 years. Base rate, pulse amplitude, pacing percentage, event rate, impedance, and i2i setting level all exhibited significant correlations with ALP and VLP longevities (P < 0.001). Programming i2i setting levels below 7 produced the greatest longevity savings. CONCLUSION: The first dual-chamber LP demonstrated adequate projected battery longevity after 12 months of use. Patient-specific device programming considerations, unique to leadless devices, may extend longevity.

• MeSH
• Atrioventricular Block therapy   diagnosis   physiopathology   MeSH
• Time Factors MeSH
• Equipment Design MeSH
• Cardiac Pacing, Artificial * methods   MeSH
• Pacemaker, Artificial * MeSH
• Middle Aged MeSH
• Humans MeSH
• Prospective Studies MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Arrhythmias, Cardiac * therapy   diagnosis   physiopathology   MeSH
• Heart Rate MeSH
• Treatment Outcome MeSH
• Electric Power Supplies * MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Clinical Trial MeSH
• Multicenter Study MeSH

BACKGROUND: The growing use of leadless pacemaker (LP) technology requires safe and effective solutions for retrieving and removing these devices over the long term. OBJECTIVES: This study sought to evaluate retrieval and removal of an active helix-fixation LP studied in worldwide regulatory clinical trials. METHODS: Subjects enrolled in the LEADLESS II phase 1 investigational device exemption, LEADLESS Observational, or LEADLESS Japan trials with an attempted LP retrieval at least 6 weeks postimplantation were included. The retrieval success rate was evaluated for all attempted retrievals. Site-reported complications associated with LP retrievals were quantified, with the severity and relationship adjudicated by an independent clinical events committee. RESULTS: There were 1,423 successful LP implants and 234 chronic LP retrieval attempts in 233 subjects. The overall retrieval success rate was 87.6% (205 of 234 attempts). The most common reason for failed retrieval (86.2%, 25 of 29 attempts) was inability to access the LP docking button. The mean time from implantation to attempted retrieval was 3.2 years (range 0.2-9.0 years) and did not significantly influence the retrieval success (P = 0.71). The clinical events committee adjudicated 11 complications in 9 subjects as being retrieval related (3.9%, 9 of 233 subjects). CONCLUSIONS: The safety and efficacy of chronic LP retrieval of an active helix-fixation device was demonstrated in an international clinical trial setting, with implant durations up to 9 years.

• MeSH
• Equipment Design MeSH
• Adult MeSH
• Pacemaker, Artificial * MeSH
• Middle Aged MeSH
• Humans MeSH
• Device Removal * methods   MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH

Photosystem II (PSII) is an intrinsic membrane protein complex that functions as a light-driven water:plastoquinone oxidoreductase in oxygenic photosynthesis. Electron transport in PSII is associated with formation of reactive oxygen species (ROS) responsible for oxidative modifications of PSII proteins. In this study, oxidative modifications of the D1 and D2 proteins by the superoxide anion (O2•-) and the hydroxyl (HO•) radicals were studied in WT and a tocopherol cyclase (vte1) mutant, which is deficient in the lipid-soluble antioxidant α-tocopherol. In the absence of this antioxidant, high-resolution tandem mass spectrometry was used to identify oxidation of D1:130E to hydroxyglutamic acid by O2•- at the PheoD1 site. Additionally, D1:246Y was modified to either tyrosine hydroperoxide or dihydroxyphenylalanine by O2•- and HO•, respectively, in the vicinity of the nonheme iron. We propose that α-tocopherol is localized near PheoD1 and the nonheme iron, with its chromanol head exposed to the lipid-water interface. This helps to prevent oxidative modification of the amino acid's hydrogen that is bonded to PheoD1 and the nonheme iron (via bicarbonate), and thus protects electron transport in PSII from ROS damage.

• MeSH
• alpha-Tocopherol chemistry   metabolism   MeSH
• Amino Acids chemistry   metabolism   MeSH
• Arabidopsis enzymology   genetics   radiation effects   MeSH
• Photosynthesis physiology   radiation effects   MeSH
• Photosystem II Protein Complex chemistry   genetics   metabolism   MeSH
• Hydroxyl Radical chemistry   metabolism   MeSH
• Protein Interaction Domains and Motifs MeSH
• Intramolecular Transferases chemistry   genetics   metabolism   MeSH
• Protein Conformation, alpha-Helical MeSH
• Protein Conformation, beta-Strand MeSH
• Oxygen chemistry   metabolism   MeSH
• Models, Molecular MeSH
• Mutation MeSH
• Oxidation-Reduction MeSH
• Superoxides chemistry   metabolism   MeSH
• Light MeSH
• Thermodynamics MeSH
• Thermosynechococcus enzymology   genetics   radiation effects   MeSH
• Thylakoids enzymology   genetics   radiation effects   MeSH
• Protein Binding MeSH
• Binding Sites MeSH
• Iron chemistry   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

BACKGROUND: The clinical utilization of leadless pacemakers (LPs) as an alternative to traditional transvenous pacemakers is likely to increase with the advent of dual-chamber LP systems. Since device retrieval to allow LP upgrade or replacement will become an important capability, the first such dual-chamber, helix-fixation LP system (Aveir DR; Abbott, Abbott Park, IL) was specifically designed to allow catheter-based retrieval. In this study, the preclinical performance and safety of retrieving chronically implanted dual-chamber LPs was evaluated. METHODS: Atrial and ventricular LPs were implanted in the right atrial appendage and right ventricular apex of 9 healthy ovine subjects. After ≈2 years, the LPs were retrieved using a dedicated transvenous retrieval catheter (Aveir Retrieval Catheter; Abbott) by snaring, docking, and unscrewing from the myocardium. Comprehensive necropsy/histopathology studies were conducted to evaluate device- and procedure-related outcomes. RESULTS: At a median of 1.9 years postimplant (range, 1.8-2.6), all 18 of 18 (100%) LPs were retrieved from 9 ovine subjects without complications. The median retrieval procedure duration for both LPs, from first-catheter-in to last-catheter-out, was 13.3 minutes (range, 2.5-36.4). Postretrieval, all right atrial, and right ventricular implant sites demonstrated minimal tissue disruption, with intact fibrous tissue limited to the distal device body. No significant device-related trauma, perforation, pericardial effusion, right heart or tricuspid valve injury, or chronic pulmonary thromboembolism were observed at necropsy. CONCLUSIONS: This preclinical study demonstrated the safe and effective retrieval of chronically implanted, helix-fixation, dual-chamber LP systems, paving the way for clinical studies of LP retrieval.

• MeSH
• Equipment Design MeSH
• Atrial Fibrillation * MeSH
• Pacemaker, Artificial * MeSH
• Humans MeSH
• Lipopolysaccharides MeSH
• Sheep, Domestic MeSH
• Sheep MeSH
• Heart Ventricles MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Cíl práce: Cílem práce je představit diagnostický a terapeutický postup při raritním poranění ramenního pletence u muže středního věku. Materiál a metody: Autoři popisují diagnostickou a chirurgickou intervenci u 40letého pacienta s akutním poraněním pravého ramenního pletence. U pacienta byla diagnostikována zadní luxace ramenního a sternoklavikulárního kloubu na téže straně. Autoři se v literatuře nesetkali s obdobným případem koincidentního poranění. Předmětem terapeutického postupu autorů bylo ošetření obou postižených lokalit. Zadní luxace ramene byla nejprve reponována pod artroskopickou kontrolou, následně byla otevřeně z miniiarthrotomie provedena refixace šlachy m. subscapularis kotvou Helix k řešení impresivní fraktury hlavice pažní kosti (charakteru reverzního Hill-Sachsova defektu). Sternoklavikulární luxace byla otevřeně reponována a mediální konec klíčku byl fixován v reponované poloze do sterna pomocí ortokordových vláken. Po výkonu byla pacientovi naložena ortéza na čtyři týdny, následně pacient absolvoval rehabilitaci. Výsledky: Pacient je šest měsíců od poranění a po léčbě spokojený s funkčností končetiny, není omezen v denních činnostech, pracuje bez omezení a taktéž sportuje bez omezení, flexe v rameni dosahuje 170°, zevní rotace 75°, vnitřní rotace 45° a abdukce 140 st. Klíční kosti jsou symetrické. Závěr: Zmíněný operační postup představuje možnost léčby daného typu poranění, z našeho pohledu jej doporučujeme.

Objective: The objective of this case report is to present the diagnostic and therapeutic procedure of a rare injury to the shoulder girdle in a middle-aged male patient. Materials and methods: The authors describe the diagnostic methods and type of surgery in 40 years old patient with acute injury to the right shoulder girdle. The patient was diagnosed with dorsal dislocation of the shoulder and sternoclavicular joint on the same side. 
The authors did not met with a similar injury combination in the li-terature. The therapeutic objective was treatment of both affected sites. The posterior shoulder dislocation was initially reduced under arthroscopic control, then mini-arthrotomy was performed to refix the subscapularis tendon using a Helix anchor which solved the impression fracture of the humeral head (similar to a reverse Hill-Sachs lesion). Sternoclavicular dislocation was treated by open reduction and fixation of the medial end of the cla-vicle in anatomical position to the sternum using Ortocord fibers. After surgery, the arm was fixed in a brace for four weeks, followed by physiotherapy. Results: The patient is 6 months after the injury and this treatment regime satisfied with limb function, he is 
neither limited in daily activities, nor at work or sports. Range of motion of the shoulder joint: flexion up to 170°, rotation (external-internal): 75°-0-45°, abduction 140°. Clavicles are symmetrical. Conclusion: The described method of treatment is a good option for this rare type of injury, which we recommend based on our modest experience.

• Keywords
• reverzní Hill-Sachsův defekt, sternoklavikulární luxace, zadní luxace ramene,
• MeSH
• Arthroscopy methods   MeSH
• Adult MeSH
• Humans MeSH
• Shoulder Dislocation * diagnosis   surgery   MeSH
• Tomography, X-Ray Computed MeSH
• Radiography MeSH
• Treatment Outcome MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Male MeSH
• Publication type
• Case Reports MeSH

• MeSH
• Genome MeSH
• Genes MeSH
• Publication type
• Monograph MeSH

• Conspectus
• Obecná genetika. Obecná cytogenetika. Evoluce
• Učební osnovy. Vyučovací předměty. Učebnice
• NML Fields
• genetika, lékařská genetika
• biologie

• MeSH
• DNA MeSH
• Genetics MeSH
• Genes MeSH
• Molecular Biology MeSH
• Publication type
• Monograph MeSH

• Conspectus
• Obecná genetika. Obecná cytogenetika. Evoluce
• NML Fields
• genetika, lékařská genetika
• biologie