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

Abstract

Rapidly switching multidirectional shock delivery required lower shock energy for ventricular fibrillation termination and may be a safer alternative for restoring cardiac sinus rhythm.

System for open-chest, multidirectional electrical defibrillation

“…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.…”

“…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).…”

“…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.)…”

“…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.…”

“…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.…”