RELATIVE CONTRIBUTION OF PADDLE ELECTRODE AREA AND EDGE LENGTH TO TRANSTHORACIC IMPEDANCE FROM A DC DEFIBRILLATOR DISCHARGE.

Previous studies have indicated that the transthoracic impedance to direct current defibrillator discharge decreases with increasing paddle electrode size. When round electrodes are used, increasing size results in both an increased electrode area and an increased electrode edge length. The purpose of this study was to determine which of these parameters is more important in decreasing the transthoracic impedance to dc defibrillator discharge. It is concluded that increasing the edge length of defibrillator paddle electrode contributes to decreasing the transthoracic impedance of larger electrode to dc defibrillator discharge. However, this contribution is relatively small and therefore is not useful in the design of paddle electrodes for defibrillation and cardioversion.