Which of the following is a common ECG finding in hypokalemia?

In hypokalemia, one of the hallmark changes observed on ECG is QT prolongation. This phenomenon occurs because low levels of potassium can disrupt the normal electrical activity of the heart, particularly by prolonging the repolarization phase of the cardiac action potential. The QT interval reflects the time taken for the heart's ventricles to depolarize and repolarize, and in the presence of hypokalemia, this time is notably increased, resulting in a longer QT interval.

Additionally, prolonged QT intervals can lead to serious arrhythmias, including Torsades de Pointes, which is a type of polymorphic ventricular tachycardia that can be precipitated by low potassium levels. Monitoring the QT interval is crucial in patients with hypokalemia to prevent potential life-threatening cardiac events.

The other options given do not directly relate to the primary effects of hypokalemia on the ECG. For instance, ST elevation is commonly associated with acute myocardial ischemia rather than low potassium levels. Supraventricular tachycardia is a rapid heart rhythm that can occur due to various factors but is not specifically linked to hypokalemia. Bradycardia reflects a slower heart rate and is typically associated with other conditions like increased vagal tone or various medications