VOLTAGE-SENSITIVE DYE RECORDINGS OF ELECTROPHYSIOLOGICAL ACTIVATION IN A LANGENDORFF-PERFUSED MOUSE HEART

The pattern of electrophysiological activation of adult mouse ventricl es was measured with the use of voltage-sensitive dye methods. Di-4-AN EPPS was used to monitor membrane potential as small changes in fluore scence, which were detected by a state of the art, cooled, charged cou pled device camera/image intensifier system. The extremely rapid condu ction velocity, coupled with the small size of this preparation, neces sitated taking these measurements at room temperature (22 to 23 degree s C). Initial experiments demonstrate that ventricular activation can be identified and its conduction pattern can be monitored reproducibly and with high resolution for extended time periods (10 to 20 mins) du ring spontaneous activity.