A patient with atrial fibrillation will show what characteristic on an ECG?

In atrial fibrillation, the hallmark characteristic observed on an ECG is the absence of distinct P waves. This arrhythmia arises from chaotic electrical activity in the atria, leading to irregular and often rapid heartbeats. Because the atria do not contract effectively as a synchronised unit, the P wave - which represents atrial depolarization in a normal rhythm - is either absent or not identifiable. Instead, the ECG will show irregularly spaced QRS complexes indicative of ventricular depolarization occurring in response to erratic atrial signals. This lack of P waves along with the irregularity of the rhythm is what distinguishes atrial fibrillation from other types of arrhythmias. Recognizing this pattern is crucial for accurate diagnosis and management of the condition.