Rapidly switching multidirectional defibrillation: Reversal of ventricular fibrillation with lower energy shocks

Viana, Marcelo Almeida; Bassani, Rosana A.; Petrucci, Orlando; Marques, Denilson; Bassani, José Wilson Magalhães

doi:10.1016/j.jtcvs.2014.07.035

Cited by 6 publications

(8 citation statements)

References 32 publications

(49 reference statements)

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“…The delivered discharges in the two defibrillation modalities, and at the 3 defibrillator outputs during multidirectional stimulation, reached the same peak voltage and had similar time course at a given energy level, which eliminated a possible bias caused by variation in the pattern of stimulation in different directions and/or modalities introduced by the use of different equipments for each pathway. The cardiac impedance estimated during application of the defibrillatory pulses (61 ± 11 Ω; Viana et al, 2014) was in agreement with the standard 50 Ω resistive load assumed for development of cardiac stimulation devices (American National Standards Institute…, 1996;Associação Brasileira de Normas Técnicas…, 2005) and in the project of the present defibrillator.…”

Section: Discussionsupporting

confidence: 80%

“…These results indicate that, provided that the stimulus was sufficiently short, application of defibrillatory shocks in 3 directions decreased the stimulus energy required for defibrillation, compared to the use of the conventional, unidirectional approach. For further comparison in a larger experimental sample with 20 ms-long shocks, see Viana et al (2014).…”

Section: Resultsmentioning

confidence: 99%

“…The output waveform was recorded with a DSO3062A oscilloscope (Agilent Technologies Inc., Santa Clara, CA, USA) for confirmation of the pulse peak voltage, current and duration. The in vivo preparation was similar to that described by Petrucci et al (2003) and Viana et al (2014). Briefly, the animals, sedated with ketamine (10 mg.kg -1 , i.m.)…”

Section: Bench Testing Of the Defibrillatormentioning

confidence: 99%

“…Experiments lasted no longer than 4 h. Within 15 s after VF induction by epicardial, low energy DC stimulation (Euler et al, 1999;Viana et al, 2014), either unidirectional or multidirectional defibrillation was attempted. If the arrhythmia could be reversed, a shock of the same modality, but lower energy, was applied 5-15 min later.…”

Section: In Vivo Test Of the Defibrillatormentioning

confidence: 99%

“…In a recent study, we reported improved in vivo defibrillation by applying stimuli through 3 pathways using a single defibrillator for both unidirectional and multidirectional stimulation (Viana et al, 2014). In the present article, we describe, from the constructive point of view, the system used in the previous study, composed of an electrical defibrillator and electrode-bearing paddles for rapid shock delivery on the epicardial surface in up to 3 directions, with a special focus on the influence of shock duration on the effectiveness of defibrillation.…”

Section: Introductionmentioning

confidence: 99%

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System for open-chest, multidirectional electrical defibrillation

et al. 2016

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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.

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Section: Discussionsupporting

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Bench Testing Of the Defibrillatormentioning

confidence: 99%

Section: In Vivo Test Of the Defibrillatormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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