High resolution optical mapping of cardiac action potentials in freely beating rabbit hearts

Optical mapping of action potentials (APs) has become important tools for the cardiac electrophysiology. However, cardiac contraction unavoidably produces motion artifacts (MA) in optical signal. We developed a method to suppress motion artifacts without arresting the hearts. METHODS: Using a dual-wavelength optical mapping system, APs were recorded on the surface of an isolated rabbit heart. Transmembrane APs were simultaneously recorded using glass microelectrodes. We eliminated MA in a frontal plane by a motion tracking technique. Subsequently, a dual-wavelength ratiometric method was used to remove MA in a vertical direction to a frontal plane. RESULTS: MA were effectively removed from optical signals. Action potential duration measured from optical signals corresponded with those measured from microelectrodes (r²=0.9677). Our method enables us to map action potentials in freely beating hearts.