528 channel system for the acquisition and display of defibrillation and electrocardiographic potentials
A 528 channel data acquisition and display system has been developed which allows us to study electrical therapies of the heart. The acquisition system records defibrillation shock potentials and electrograms from the heart. The display system presents animated sequences of potentials or their derivative on a two dimensional projection of the recording array. Using this system, we measured the distribution of potentials on the heart during transvenous defibrillation shocks in pigs. For failed defibrillation shocks near threshold, we studied the post-shock activation sequences that led to reinitiation of fibrillation. The earliest epicardial activation following failed shocks was in the region of the heart opposite and inferior to the right ventricular electrode. The first few beats were organized and rapid. The rapid activation led to unidirectional block and reentry after 3 or 4 beats. This mapping system provides a comprehensive tool for studying electrical therapies of the heart.