We describe a new approach that combines several techniques to visualize abnormal electrical activity caused by regional hypoperfusion of myocardial tissue. A flexible microcannula was inserted into the left anterior descending artery of Langendorff perfused rat hearts, an air‐tight seal between the coronary artery and the cannula was created, and an HPLC pump was used to deliver a specified flowrate through the microcannula. The size and geometry of the affected coronary bed and the degree of ischemia was monitored by the acquiring the epicardial fluorescence of nicotinamide adenine dinucleotide (NADH). High resolution optical mapping of NADH and transmembrane potential was then conducted using a dual CCD camera system. The ECG was acquired using surface electrodes. The described method provides a powerful new tool to assess how coronary flow rate affects the degree of local ischemia and to associated it with abnormal patterns of electrical activity. Financial support by the American Heart Association, MidAtlantic Affiliate and the NIH (HL076722) is gratefully acknowledged.