---
title: The Heart of the Matter download | ZOLL
description: There has been a lot of discussion about “low-energy” biphasic defibrillation versus “high-energy” biphasic as well as average current versus peak current.
---

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# The Heart of the Matter: What Really Defibrillates the Heart?

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There has been a lot of discussion about “low-energy” biphasic defibrillation vs. “high-energy” biphasic, as well as average current vs. peak current.

Although delivered energy levels are selected for defibrillation, it is the transmyocardial current flow that achieves defibrillation; the electrical current correlates well with successful defibrillation and cardioversion.

The American Heart Association Scientific Guidelines for Resuscitation clearly state: “Modern defibrillators deliver current based on stored energy. Because it is accepted that defibrillation is accomplished by the passage of sufficient current through the heart, the concept of current-based defibrillation is appealing. Energy is a nonphysiologic descriptor of defibrillation despite its entrenchment in traditional jargon.”1

All ZOLL® defibrillators deliver a Rectilinear Biphasic waveform (RBW) that provides more current than the high-energy biphasic others use. This capability is particularly important for the difficult-to-defibrillate, high-impedance patient.

This document is intended to provide clarity around the terminology by reviewing the scientific literature.

 

1 Link MS, Atkins DL, et al. Automated external defibrillators, defibrillation, cardioversion, and pacing. 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010;122(suppl 3):S706 –S719

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