Advanced Patient Assessment Practice Exam

Which of the following would describe the ECG of a patient with atrial fibrillation?

1. Large bizarre QRS complexes

2. No identifiable QRS complexes

3. Chaotic baseline between QRS complexes

4. Regular ventricular response

The correct answer is: Chaotic baseline between QRS complexes

The ECG of a patient with atrial fibrillation is characterized by a chaotic baseline between QRS complexes. This chaotic activity represents the irregular and rapid electrical impulses originating from the atria, which leads to the ineffective contraction of the atrial muscles. In atrial fibrillation, the atria do not contract in a coordinated manner, resulting in fibrillation waves that appear as a wavy baseline on the ECG. The QRS complexes themselves can be present and will appear normal in morphology; however, they occur irregularly, making it challenging to predict the timing of their appearance. The absence of organized atrial contractions and the irregular rhythm are critical features of atrial fibrillation, distinguishing it from other arrhythmias. The chaotic baseline primarily reflects the disorganized atrial electrical activity, hence why this choice is indicative of atrial fibrillation.