High speed optical imaging of spiral waves in cardiac tissue

Many cardiac arrhythmias are hypothesized to be composed of one or more reentrant circuits. Using a 10/spl times/10 photodiode array and the potentiometric dye di-4-ANEPPS, the authors have recorded high-speed "movies" of the initiation, maintenance, and termination of spiral waves artificially induced in thin isolated slices of canine ventricular tissue. These spiral waves, which rotate at approximately 4-5 Hz, could be terminated consistently with field strengths greater than /spl sim/7 V/cm. Successful termination occurred when all regions of the tissue were simultaneously depolarized to excitation levels greater than /spl sim/30% of the normal action potential amplitude. Thus, this technique of high-speed optical imaging affords a unique method for the quantitative investigation of spiral waves and their interactions with external fields.<>