Three-dimensional bipolar myocardial potential gradient mapping during transthoracic defibrillation

Measurement of the potential gradient distribution in the myocardium during electrical defibrillation is important for optimizing the delivery of the defibrillatory pulse. In the past, myocardial potential gradient mapping has been achieved mainly with a unipolar approach that exhibits a sensitivity to measurement errors. To avoid this problem, a bipolar three-axis single-plunge electrode array has been developed and used for multisite mapping of the myocardial potential gradient during transthoracic defibrillation. Calibration of the electrode array is performed in an electrolytic tank where a known, uniform electric field can be produced. Voltage outputs from the electrode arrays are interfaced to a 128-channel data acquisition system specially built for collecting data during high voltage defibrillation shocks. Details of the electrode array and calibration process are presented together with the data acquisition system.