What might a prolonged QT interval increase the risk of?

A prolonged QT interval is a measurement on an electrocardiogram (EKG) that represents the time it takes for the heart's ventricles to repolarize after each contraction. When the QT interval is longer than normal, it can lead to a condition called Torsades de Pointes, a type of polymorphic ventricular tachycardia. This arrhythmia can result in sudden cardiac arrest if not promptly addressed. The risk of this and other life-threatening ventricular arrhythmias is significantly heightened when the QT interval is prolonged.

In contrast, while bradycardia involves a slowed heart rate and myocardial infarction refers to heart tissue damage due to reduced blood flow, they are not directly linked to the effects of a prolonged QT interval in the same manner as tachyarrhythmias. Atrial fibrillation, characterized by rapid and irregular beating of the atria, is generally associated with other factors such as structural heart changes and is not a direct consequence of QT interval prolongation. Therefore, the most pertinent risk associated with a prolonged QT interval is the increased likelihood of developing tachyarrhythmias.