Knowledge of the basic mechanisms of cardiac excitation is a prerequisite to the understanding of cardiac arrythmias and their response to therapy. The goal of this book is to provide readers unacquainted with the matter with the information necessary to develop pathophysiologically oriented clinical reasoning in this area. Besides covering normal aspects of cardiac cellular and tissue electrophysiology, An Introduction to Cardiac Electrophysiology illustrates recently acquired information on electronic abnormalities associated with cardiac disease and on molecular mechanisms of anti-arrhythmic drug action. The language used is suitable to address non-specialists, and the reference to physics has been limited to very basic principles. Enclosed with the book is an interactive computer model for cardiac action potential, that can be easily run on any IBM compatible PC, thus allowing readers to test the effects of changes in individual ionic currents on the shape and properties of the cardiac act.