Sick Beats: Scientists Revive Hearts to Study Erratic Rhythms

The cameras track electrical impulses to identify sources of signal disruptions that can make hearts beat too slowly, too quickly, or out of rhythm. The rhythm is set by synchronized pumping in the heart's two upper chambers, called the atria, and in its two lower chambers, called the ventricles. Disruptions in the heart's electrical system can cause abnormal beating, or arrhythmia.