Which ECG finding is characteristic of Atrial Fibrillation?

Which ECG finding is characteristic of Atrial Fibrillation?

• A. No P waves
• B. Regular rhythm with P waves preceding each QRS
• C. Sawtooth pattern
• D. Wide QRS complexes

Answer: (A)

In atrial fibrillation the atrial electrical activity becomes chaotic, so there are no discrete atrial depolarizations visible on the ECG. That means you don’t see distinct P waves; instead, there may be irregular, fibrillatory activity in the baseline and an irregularly irregular ventricular rate as the AV node conducts impulses at variable intervals. This combination—no clear P waves with an irregular rhythm—is the hallmark feature of AF. Knowing what the other patterns represent helps: a regular rhythm with P waves before each QRS is normal sinus rhythm, a sawtooth pattern points to atrial flutter, and wide QRS complexes suggest a ventricular conduction problem or a wide complex rhythm rather than AF.

In atrial fibrillation the atrial electrical activity becomes chaotic, so there are no discrete atrial depolarizations visible on the ECG. That means you don’t see distinct P waves; instead, there may be irregular, fibrillatory activity in the baseline and an irregularly irregular ventricular rate as the AV node conducts impulses at variable intervals. This combination—no clear P waves with an irregular rhythm—is the hallmark feature of AF.

Knowing what the other patterns represent helps: a regular rhythm with P waves before each QRS is normal sinus rhythm, a sawtooth pattern points to atrial flutter, and wide QRS complexes suggest a ventricular conduction problem or a wide complex rhythm rather than AF.