Which description matches atrial fibrillation on ECG?

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Multiple Choice

Which description matches atrial fibrillation on ECG?

Atrial fibrillation is defined by chaotic, disorganized atrial activity that leads to an irregularly irregular ventricular response and the absence of discrete P waves on the ECG. In AF, the atria fire at many different foci, so there is no coordinated atrial depolarization, which is why P waves are not seen as distinct waves before each QRS. Instead you may see tiny, erratic fibrillatory waves and the R–R intervals vary unpredictably, making the rhythm irregularly irregular. The QRS complexes are usually narrow because ventricular conduction is through the normal His-Purkinje system, though they can appear wide if there is aberrant conduction or a preexisting bundle branch block. This description fits AF best because it emphasizes the irregularly irregular rhythm and the absence of discrete P waves. By contrast, a regular rhythm with sawtooth P waves points to atrial flutter, a regular rhythm with normal P waves indicates sinus rhythm, and a wide complex tachycardia suggests ventricular tachycardia or SVT with aberrancy rather than classic atrial fibrillation.

Atrial fibrillation is defined by chaotic, disorganized atrial activity that leads to an irregularly irregular ventricular response and the absence of discrete P waves on the ECG. In AF, the atria fire at many different foci, so there is no coordinated atrial depolarization, which is why P waves are not seen as distinct waves before each QRS. Instead you may see tiny, erratic fibrillatory waves and the R–R intervals vary unpredictably, making the rhythm irregularly irregular. The QRS complexes are usually narrow because ventricular conduction is through the normal His-Purkinje system, though they can appear wide if there is aberrant conduction or a preexisting bundle branch block.

This description fits AF best because it emphasizes the irregularly irregular rhythm and the absence of discrete P waves. By contrast, a regular rhythm with sawtooth P waves points to atrial flutter, a regular rhythm with normal P waves indicates sinus rhythm, and a wide complex tachycardia suggests ventricular tachycardia or SVT with aberrancy rather than classic atrial fibrillation.

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