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Defibrillation Current and Impedance are Determinants of Defibrillation Energy Requirements

1988; Wiley; Volume: 11; Issue: 11 Linguagem: Inglês

10.1111/j.1540-8159.1988.tb06340.x

1540-8159

PAUL DORIAN, MICHELE J. WANG,

ECG Monitoring and Analysis

The relationship between various electrical descriptors of shocks for cardiac defibriliation is incompletely understood. Defibrillating energy, current, impedance and pulse duration were measured in 18 dogs. They were subject to repeated fibrillation‐defibrillation through epicardial patches, with shocks of preset energy and voltage and variable pulse duration, impedance and peak current. Current and energy requirements for defibrillation were calculated. Energy requirements were positively correlated with pulse duration and interelectrode impedance (r = .70, P < 0.01). Correcting for heart weight, these correlations were no longer present. However, peak current was correlated with energy requirements both before (r = ‐0.62, P < 0.05) and after (r = ‐0.76, P < 0.01) correcting for heart weight, with energy requirement decreasing as peak current/g heart increased. Current requirements were significantly less variable between animals than energy requirements (.027 ± .012 joules/g vs .016 ± .003 Amps/g), suggesting that current per unit heart weight may be a better descriptor than energy/or the ability to defibrillate.