Simple optical methods for the recognition of atrial flutter, especially at slow atrial rates.

MANY ELECTROCARDIOGRAPHERS have discussed the differentiation of atrial flutter from atrial tachycardia with block. Some have concluded that there is no difference;' others, including ourselves, hold the opposite view.2 We find the methods described here useful in making the distinction in practice and of interest in their bearing on the theoretical mechanism of atrial flutter. There are three areas of confusion relevant to the differentiation. Much of the first, intellectual confusion, could be dispelled by a return to the well-phrased description of flutter by Sir Thomas Lewis:3 "The Auricular Complexes in Electrocardiograms.-The beating of the auricles usually displays itself characteristically in these curves. At each cycle in leads II and III the curve ascends sharply to a blunt summit and returns more gradually....