12 lead ECG of atrial flutter

The 12 lead electrocardiogram (ECG) of atrial flutter shows a regular rhythm with a narrow QRS complex. Flutter waves are present, best seen in leads II, III, and aVF (*). In this ECG, the flutter waves are negative in leads II, III, and aVF, and positive in lead V1. One flutter wave is obvious between the QRS complexes, while the second one is superimposed on the terminal portion of the QRS complex; hence there is 2:1 atrioventricular nodal block, which is the most common presentation for atrial flutter.