[Atypical flutters]

Abstract

Typical atrial flutter may now be definitely treated in a single session. However, the very meaning of the term, atrial flutter, is confusing because it is a multiple entity. In fact, flutters may be classified with respect to their electrocardiographic and electrophysiological features. In addition to typical common atrial flutter with biphasic, predominantly negative F waves in the inferior leads and positive F waves in V1 due to an anticlockwise macro-reentry circuit localised to the right atrium, there are other forms which may be described as typical in that they pass through the cavo-tricuspid isthmus. They include typical flutter with inverted rotation, short loop inferior flutter and flutter with a double reentry circuit. In 2001, it would seem licit to call all flutters which do not pass through the cavotricuspid isthmus atypical, independently of their surface ECG appearances. The term flutter still refers to a continuous electrical activity with absence of an isoelectric line in at least one lead but with extremely variable ECG features. They may be classified as flutter on pre-existing lesions, with right or left atrial macro-reentry circuits. The ECG appearance is then that of very atypical flutter. More recently, flutters with circuits passing through the coronary sinus have been described. Ablation of the muscle of the coronary sinus seems to be able to treat this type of flutter, the prevalence of which is not yet known.