**Question:** Following shown condition is least common in:

A. Atrial flutter
B. Atrial fibrillation
C. Ventricular tachycardia
D. Ventricular fibrillation

**Core Concept:**
The question is testing our knowledge of cardiac arrhythmias and their prevalence in clinical practice. Arrhythmias are abnormal heart rhythms caused by abnormal electrical impulses in the heart. The four options listed are common types of cardiac arrhythmias.

**Why the Correct Answer is Right:**
D. Ventricular fibrillation (VF) is the least common arrhythmia among the options. Ventricular fibrillation is an extreme form of ventricular tachycardia (VT), characterized by rapid, chaotic contractions of the ventricles due to abnormal electrical activity. VF is often life-threatening and requires immediate treatment, such as defibrillation.

**Why Each Wrong Option is Incorrect:**
A. Atrial flutter (AFl) is a common arrhythmia, typically characterized by rapid, regular contractions of the atria. It is not as rare as VF.
B. Atrial fibrillation (AF) is another common arrhythmia, also involving rapid, irregular contractions of the atria. It is more common than VF.
C. Ventricular tachycardia (VT) is a group of arrhythmias characterized by rapid contractions of the ventricles, which can be life-threatening depending on the rate and rhythm. It is not as rare as VF, but less common than AF and AFl.

**Clinical Pearl:**
Understanding the prevalence of different arrhythmias is crucial for healthcare providers to recognize and manage them appropriately. Knowing the core concepts behind each arrhythmia can help in distinguishing between benign and potentially life-threatening arrhythmias, allowing for timely treatment and improving patient outcomes.