In the past decade, major progress has been made in understanding mec- nisms of arrhythmias. This progress stems from much-improved experim- tal, genetic, and computational techniques that have helped to clarify the roles of speci?c proteins in the cardiac cycle, including ion channels, pumps, - changer, adaptor proteins, cell-surface receptors, and contractile proteins. The interactions of these components, and their individual potential as therap- tic targets, have also been studied in detail, via an array of new imaging and sophisticated experimental modalities. The past 10 years have also...