Long QT syndrome is a heart condition that causes uncontrolled arrhythmias. It is the most common cause of unexplained deaths and affects approximately 1 in every 2000 individuals. People with long QT syndrome have a structural defect in the ion channels of their heart muscle. A defect in these ion channels causes an abnormality in their heart's electric conduction system. This defect in their heart makes them prone to having uncontrollable, fast and chaotic heartbeats (arrhythmias).
