Which of the following best describes the P wave in Atrial Fibrillation?

• A. Prominent and identifiable
• B. Absent
• C. Consistent in morphology
• D. Inverted in lead II

Answer: (B)

In Atrial Fibrillation (AF), the characteristic finding is that the P wave is absent. This is due to the chaotic electrical activity in the atria that leads to ineffective contractions and an irregular, often rapid heart rhythm. Instead of distinct P waves preceding each QRS complex, the electrical activity is disordered, resulting in a lack of organized atrial depolarization.

In this condition, the absence of identifiable P waves on the ECG is a key diagnostic criterion, as they indicate that the atria are not contracting effectively and there is no coordinated atrial depolarization. This reflects the hallmark of atrial fibrillation, where the atria are quivering rather than beating in a regular rhythm, contributing to the irregular ventricular response observed on the ECG.

Thus, identifying the absence of P waves in the context of atrial fibrillation is crucial for accurate diagnosis and understanding the underlying pathophysiology of this rhythm disturbance.