Which characteristic is typically observed on an ECG for atrial flutter?

• A. Irregular QRS complexes
• B. A flat baseline
• C. A saw-toothed pattern
• D. Steady straight lines

Answer: (C)

Atrial flutter is characterized by a distinctive saw-toothed pattern, most commonly referred to as “F-waves” or “flutter waves.” These are rapid electrical impulses that occur in the atria, creating a “saw-tooth” appearance on the ECG, particularly in the inferior leads (II, III, and aVF). This pattern is a result of continuous atrial reentry, which can lead to numerous atrial contractions that outpace the ventricular response.

The presence of this saw-toothed pattern is critical in diagnosing atrial flutter, as it differentiates this arrhythmia from other conditions such as atrial fibrillation, where the waves are more chaotic and irregular, potentially leading to a less defined or absent baseline. Therefore, recognizing the saw-toothed pattern on the ECG assists healthcare providers in quickly identifying atrial flutter and initiating appropriate management.