Cardiac potential and potential gradient fields generated by single, combined, and sequential shocks during ventricular defibrillation.

BACKGROUNDPotential gradient field determination may be a helpful means of describing the effects of defibrillation shocks; however, potential gradient field requirements for defibrillation with different electrode configurations have not been established.METHODS AND RESULTSTo evaluate the field requirements for defibrillation, potential fields during defibrillation shocks and the following ventricular activations were recorded with 74 epicardial electrodes in 12 open-chest dogs with the use of a computerized mapping system. Shock electrodes (2.64 cm2) were attached to the lateral right atrium (R), lateral left ventricular base (L), and left ventricular apex (V). Four electrode configurations were tested: single shocks of 14-msec duration given to two single anode-single cathode configurations, R:V and L:V, and to one dual anode-single cathode configuration, (R+L):V; and sequential 7-msec shocks separated by 1 msec given to R:V and L:V (R:V----L:V). Defibrillation threshold (DFT) current was significantly...