QT prolongation occurs when the heart muscle takes longer to contract and relax than usual. It can affect heart rhythms and lead to sudden cardiac arrest. The heart is a muscle that contracts and ...

A prolonged QT interval has a variety of causes and can be a very serious ECG finding, as it may lead to the potentially fatal arrhythmia polymorphic ventricular tachycardia (Torsades de Pointes). See ...

Congenital long-QT syndrome is a disorder resulting in ventricular arrhythmias and sudden death. The most common forms of the long-QT syndrome, types 1 and 2, are caused by mutations in the ...