System for open-chest, multidirectional electrical defibrillation

Abstract

Introduction: Cardiomyocytes are more sensitive to stimulatory electrical fields when the latter are applied longitudinally to the cell major axis. In the whole heart, cells have different spatial orientations, which may limit the effectiveness of conventional electrical defibrillation (i.e., shock delivery in a single direction). This article describes the constructive aspects of a portable system for rapidly-switching, multidirectional stimulus delivery, composed of an electrical defibrillator and multielectrode-bearing paddles for direct cardiac defibrillation. Methods:The defibrillator delivers monophasic, truncated monoexponential waveforms with energy up to 7.3 J. Upon selection of the defibrillation modality (unidirectional or multidirectional), shock delivery is triggered through 1 or 3 outputs. In the latter case, triggering is sequentially switched to the outputs, without interval or temporal overlap. Each paddle contains 3 electrodes that define shock pathways spaced by 60°. The system was tested in vivo for reversal of experimentally-induced ventricular fibrillation in healthy swine, using 30-and 20-ms long shocks (N= 4 in each group). Results: The defibrillator delivers identical stimulus waveforms through all outputs in both stimulation modalities. In all animals, successful defibrillation required lower shock energy when 20 ms-long stimuli were applied in 3 directions, compared to a single direction. However, performance was poorer with multidirectional defibrillation for 30 ms-long shocks. Conclusion: The delivery of identical shock waveforms allowed confirmation that multidirectional defibrillation can promote restoration of sinus rhythm with lower shock energy, which may reduce myocardial electrical damage during defibrillation. Nevertheless, increase in shock duration greatly impairs the effectiveness of this defibrillation modality.

New insight on the relationship between lethal electrical fields versus cardiomyocyte orientation

“…Our work was able to provide information about the behavior of cell lethality as a function of E direction and cell orientation, not only by showing that there is an increase in the probability of cell lethality, but also how this increase is happening. Results showing how cell lethality is affected by HEF for directions other than 0º and 90º were absent in the literature and could contribute for the design of new defibrillation protocols (Viana et al, 2016), by providing data on an E upper limit for cell survival, and also support further works in areas related to electropermeabilization and cell/tissue stimulation. Furthermore, these data could be used as adjusting or comparing parameters for computational models and simulations.…”

Rancang Bangun Deffibrilator Dengan Joule Rendah

“…Ada 2 mode pembuangan energi yang terdapat pada alat defibrillator yaitu sinkron dan asinkron [13]. Pembuangan energi pada defibrillator dilakukan dengan menekan tombol discharge pada paddle [18], [19] yang ditempatkan pada bagian sternum dan apex. [20] Tahun 2019 Muhammad Amir Ma'ruf [13] merancang sebuah alat "Simulasi DC Shock" akan tetapi alat tersebut menghasilkan nilai energi yang dikatakan masih rendah dan tidak dilengkapi dengan mode sinkron serta masih menggunakan komparator analog.…”

A Influência Do Nitrogênio Em Aços Inoxidáveis Austeníticos Com Aplicação Em Próteses Ortopédicas

“…De maneira geral, na estimulação elétrica, objetiva-se respostas fisiológicas e integridade final da célula excitável. A estimulação elétrica é relevante em pesquisas e aplicações clínicas para corrigir arritmias cardíacas (VIANA et al, 2016), transtornos e doenças neurológicas (SCHLENSTEDT et al, 2017), alívio de dor (com uso ou não Observa-se que a indução de potencial transmembrana depende de características do campo aplicado, como intensidade e frequência (GRIMNES; MARTINSEN, 2014).…”