Background: Pacemaker-dependent patients with device infection require temporary pacing while the infection is treated. External transthoracic pacing is painful and variably effective, while temporary pacing leads are susceptible to superinfection.
Objective: To create a biological pacemaker delivered via venous catheters in a porcine model of complete heart block, providing a temporary alternative/adjunct to external pacing devices without additional indwelling hardware.
Methods: Complete atrioventricular (AV) nodal block was induced in pigs by radiofrequency ablation after the implantation of a single-chamber electronic pacemaker to maintain a ventricular backup rate of 50 beats/min. An adenoviral vector cocktail (K(AAA) + H2), expressing dominant-negative inward rectifier potassium channel (Kir2.1AAA) and hyperpolarization-activated cation channel (HCN2) genes, was injected into the AV junctional region via a NOGA Myostar catheter advanced through the femoral vein.
Results: Animals injected with K(AAA) + H2 maintained a physiologically relevant ventricular rate of 93.5 ± 7 beats/min (n = 4) compared with control animals (average rate, 59.4 ± 4 beats/min; n = 6 at day 7 postinjection; P <.05). Backup electronic pacemaker utilization decreased by almost 4-fold in the K(AAA) + H2 group compared with the control (P <.05), an effect maintained for the entire 14-day window. In contrast to the efficacy of gene delivery into the AV junctional region, open-chest, direct injection of K(AAA) + H2 (or its individual vectors) into the ventricular myocardium failed to elicit significant pacemaker activity.
Conclusions: The right-sided delivery of K(AAA) + H2 to the AV junctional region provided physiologically relevant biological pacing over a 14-day period. Our approach may provide temporary, bridge-to-device pacing for the effective clearance of infection prior to the reimplantation of a definitive electronic pacemaker.
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http://dx.doi.org/10.1016/j.hrthm.2012.04.020 | DOI Listing |
J Cardiovasc Dev Dis
December 2024
Faculty of Medicine & Health Sciences, University of Antwerp, 2610 Antwerp, Belgium.
The need for a permanent pacemaker (PPM) implantation after surgical aortic valve implantation (SAVR) is a recognized postoperative complication, with potentially long-term reduced survival. From 1987 to 2017, 2500 consecutive patients underwent SAVR with a biological valve with or without concomitant procedures such as CABG or mitral valve repair. Mechanical valves or valves in another position were excluded.
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Pitirim Sorokin Syktyvkar State University, Medical Institute, Laboratory of Translational bioinformatics and systems biology, Syktyvkar, Russia.
The review summarizes recent achievements and future prospects in the use of chronobiotics for regulating circadian rhythms regulation. Special attention is paid to the mechanisms' action, their classification, and the impact of chemical interventions on the biological clock. Chronobiotics defined as a diverse group of compounds capable of restoring disrupted circadian functions, addressing challenges such as irregular work schedules, artificial light exposure or ageing.
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John P. Hussman Institute for Human Genomics, University of Miami, FL; Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, FL.
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Background: The Antarctic krill Euphausia superba is a keystone species in the Southern Ocean ecosystem. This crustacean has an ancestral clock whose main components have been identified and characterized in the past few years. However, the second feedback loop, modulating clock gene expression through two transcription factors, VRI and PDP1, has yet to be described.
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