<title>Feasibility studies of a high-spatial-resolution cardiac optical mapping system</title>

Abstract

Optical mapping, based on voltage sensitive dyes, has become a prominent technique in the study of electrical activities within cardiac tissues. The technique is best carried out with devices that can gather optical signals with both high spatial frequency and temporal frequency. Currently, two devices dominate the field, Charge Coupled Devices (CCD) and Photo Diode Arrays (PDA). Both optical mapping techniques possess advantages and disadvantages in their performance. The objective of this investigation is to design an optical mapping system with a high spatial resolution CCD as its main component. In this feasibility study, a wavelength selective optical mapping experimental setup was designed and implemented in accordance with the fluorescence characteristics of one of the most common dyes used in cardiac mapping, di-4-ANEPPS. To test the capabilities of the optical system setup, a high resolution (512 pixels by 512 pixels, 12 bit dynamic range) CCD camera with approximately 33 ms temporal resolution is chosen as the fluorescence signal acquisition device. Experiments with di- 4-ANEPPS stained canine cardiac tissues with stimulated action potentials through external electrodes resulted in successful mapping of the distribution and propagation of the action potential wave front. A new CCD based optical mapping system was also built. It offers a 128 by 128 pixel resolution, 12 bits digitization and a temporal resolution of approximately 2 ms.