Simultaneous optical mapping system of endocardial and epicardial excitation.

The cardiac excitation propagation during arrhythmia shows a three-dimensional complex excitation behavior. Numerous optical measurements of the propagation and action potentials of the cardiac muscles have been made to elucidate the detailed arrhythmia phenomenon. The conventional optical measurement system mainly observes the action potential signal of the epicardium, and the endocardial signal measurement without incising the heart is difficult. In addition, an incised heart no longer exhibits the natural excitation behavior. Therefore, we constructed a simultaneous measurement system that integrates the conventional epicardial measurement system and the endocardial measurement system by using an endoscope for an intact heart. Then, we proposed a line-laser registration method that can match correspondence between the epicardial and endocardial images for a short period. We demonstrated that this registration method has a sub-millimeter accuracy. Subsequently, we succeeded in simultaneous optical measurement of the excitation propagation of the epicardium and endocardium of the right heart wall by using an isolated rabbit heart.