Cardiac Medicine Certification (CMC) Practice Exam

Which ECG characteristic is associated with Atrial Flutter?

1. Atrial impulses firing irregularly

2. Regular rhythm with no identifiable waves

3. Saw-toothed flutter waves

4. Flat baseline with rapid irregular spikes

The correct answer is: Saw-toothed flutter waves

Atrial flutter is characterized by the presence of distinct saw-toothed flutter waves, most often described as "F-waves." These waves occur due to a reentrant circuit in the right atrium, leading to a rapid and organized atrial activity that typically gives the ECG a characteristic appearance. In atrial flutter, these flutter waves can often be observed best in the inferior leads (II, III, and aVF), where they appear as a regular succession of saw-toothed patterns. This appearance can help differentiate atrial flutter from atrial fibrillation, which features irregularly firing atrial impulses and an absence of clear waveforms associated with atrial contraction. Thus, the distinct saw-toothed pattern is a hallmark of atrial flutter, making it the correct characteristic associated with this arrhythmia. Atrial flutter's identification via these flutter waves is crucial for appropriate diagnosis and management, as it implies a different clinical approach than other atrial arrhythmias.