Since conventional recordings of cardiac action potentials are prone to electrical artifacts during electrical stimulation, we are measuring these potentials in cells and cell cultures stained with a fluorescent voltage sensitive dye. An example of our experiments in this area is illustrated in the three photomicrographs on the right, taken at increasing magnification. By using a multichannel optical mapping system that we have developed in our lab, we are able to record the optoelectrical responses of the cells to field stimulation. Thus, we can record the electrical responses of these cellular networks to applied electric fields and analyze the data according to theoretical and computational models. The application of an electric field pulse can terminate the reentrant activity, and is a small-scale form of cardioversion.
Work is ongoing to improve our imaging capabilities.
The goal of this research is to investigate the influence of mechanical stretch on cellular cardiac electrophysiology. At the same time, we have conducted experiments on flaps of frog ventricle and have found that stretch acts much like an electrical stimulus, even to the point where it can induce arrhythmias. We plan to continue work in this area in a cultured cell system. We are beginning work to synthesize and characterize engineered cardiac tissue, starting with 3D networks of cultured cardiac cells. One approach that we are exploring is to seed isolated cells onto polymer scaffolds and to culture them in a rotating bioreactor.