Over 300,000 people die each year in the US due to sudden cardiac death. In many cases, sudden cardiac death is caused by abnormally rapid heart rhythms called tachycardias, which means the heart cannot pump adequate blood to the body. In Chaos, researchers use mice to study tachycardias and find there are intrinsic mechanisms that exist in heart tissue that they hypothesize lead to the self-termination of rapid cardiac rhythm.