Which of the following is NOT a type of ventricular arrhythmia?

Atrial flutter is indeed the correct choice that is not a type of ventricular arrhythmia. Understanding the context of arrhythmias is crucial for grasping this distinction. Ventricular arrhythmias originate in the ventricles of the heart, and they include conditions where the heart beats abnormally which can be life-threatening.

Ventricular fibrillation is a chaotic rhythm that results in the ventricles quivering instead of pumping blood effectively, leading to a significant drop in blood circulation. Ventricular tachycardia consists of a rapid heartbeat originating from the ventricles, which can impede normal blood flow. Idioventricular rhythm, characterized by a slower heart rate that may occur when the usual pacemaker (the sinoatrial node) fails, is also classified as a ventricular arrhythmia.

In contrast, atrial flutter originates in the atria and is characterized by a rapid and organized electrical activity that affects the upper chambers of the heart. This condition does not involve the ventricles directly, thus distinguishing it from ventricular arrhythmias. Understanding these classifications is important in the context of cardiac health and arrhythmias.