What is a common ECG feature associated with atrial fibrillation?

Atrial fibrillation is characterized by the absence or irregularity of P waves on an electrocardiogram (ECG). In this condition, the atria experience chaotic electrical activity leading to ineffective atrial contractions, which results in an irregular and often rapid heart rhythm. This lack of organized atrial depolarization is what contributes to the observable absence of distinct P waves on the ECG tracing.

Instead of P waves, you may observe fibrillatory waves (often seen as small, erratic oscillations) in the baseline of the ECG. The irregularity in rhythm can also cause a varying R-R interval, which further reinforces this characteristic of atrial fibrillation. The presence of narrow QRS complexes can occur since the conduction through the AV node remains normal in typical atrial fibrillation cases, while a consistent PR interval is not typically associated due to the erratic nature of atrial impulses. Understanding these features can assist clinicians in accurately diagnosing atrial fibrillation and differentiating it from other arrhythmias.