Abstract: Disclosed herein are methods and devices used to recognize the extent and deepness of infarcted tissue, such as chronic myocardial infarcted tissue. This applies to the heart tissue, but can also be used to assess cicatricial processes in other organs. Examples include injecting pulses of alternating current at a broadband of frequencies while measuring the voltage signal continuously (at a very high sampling rate) to obtain the electrical impedance (Z(f,t)) during the entire cardiac cycle. The impedance measurements may be taken using an intracavitary electrocatheter.