Disclosed are various embodiments of invasive and non-invasive systems for electrophysiological mapping of a patient's heart, where cardiac action potentials (APs) on a myocardial surface of a human heart are reconstructed. In one embodiment, the APs are reconstructed using known electrical potentials on the myocardial surface in combination with known geometries of the heart and/or the torso. A mathematical model of cardiac electrical activity may be employed that takes into account homogeneous and isotropic intracellular, extracellular, and human body electrical conductivities.