Cardiac electrophysiologic mapping and stimulation

Systems are provided for assessing the likelihood that a sample of cardiac tissue will spontaneously exhibit disordered electrical activity. These systems induce ventricular tachycardia or other disordered electrical activity in a sample of human and/or animal cardiac tissue either in vivo or in vitro. This system can be used to assess the ability of various pharmaceuticals, genetic modifications, electrical pacing, surgical ablation, or other therapeutic interventions to prevent or halt such disordered electrical activity. This system detects electrical activity from a plurality of points on the surface of the sample of cardiac tissue and generates one or more maps of monophasic action potential amplitude, monophasic action potential duration, local field amplitude, or other electrophysiological parameters of the cardiac tissue. These maps are then used to assess the likelihood that the sample will spontaneously exhibit disordered electrical activity and/or to assess the effect of a therapeutic intervention on that likelihood.