If the apparently chaotic workings of the heart can be understood, and this is done by figuring out the component of electrical control, then measures can be taken to correct various disorders. One line of study is to conduct experiments with small pieces of cardiac tissue, usually from a frog. The tissue will respond differently depending on the frequency of an electrical stimulus and the history of the paces delivered to it. By understanding the behavior of individual pieces of tissue, valuable insight is gained into the action of the heart as a whole. What is known as bifurcation behavior is also studied.
Bifurcation occurs when the response pattern shifts suddenly from one behavior to another.
For example, when the frequency of paces is increased to a fragment, contractions may change so that they alternate in strength in which a strong contraction is followed by a weaker one. If the paces continue to be accelerated, the tissue may begin to skip every other beat altogether. Part of the NSF grant is to continue these studies with individual pieces of the heart. The goal is to understand why this happens, and what happens under other pacing patterns. In addition to small pieces of cardiac tissue, studies are also being done on entire sheep hearts.