Therapies for ventricular cardiac arrhythmias.

During recent years, engineers and physicists have become increasingly interested in studying the electrical activity of the heart. Despite the fact that the heart is a complex and highly nonlinear system, its electrical behavior can be studied using a variety of experimental and clinical techniques, and can be modeled mathematically using relatively simple systems of differential equations, allowing scientists to perform both real and virtual (in silico) experiments to gain insights into its physiology and pathophysiology. Although these approaches have in recent years allowed great headway to be made into understanding the dynamic behavior of the heart, cardiac arrhythmias such as ventricular fibrillation still claim the lives of hundreds of thousands of people each year in the United States alone. Bridging the gap between understanding the mechanistic bases of arrhythmias and applying such knowledge to improving therapy presents one of the greatest challenges in the field of cardiac electrophysiology. In this review, we describe the basic electrical properties and dynamic behavior of the heart and review the current state of the art in ventricular arrhythmia therapy. We also discuss some possibilities for future therapies, with the hope that such informed speculation will promote new investigations in these areas.