Atrial flutter

Atrial flutter is a supraventricular arrhythmia in which the atria contract at a rate of 250-350 bpm. The ventricular response depends on the degree of block at the atrioventricular node.

This rhythm is commonly associated with atrial fibrillation, into which it may degenerate. Atrial fibrillation may also convert to atrial flutter. Because of alterations in atrial activation, the ECG often fluctuates between both rhythms in the same patient.

Often the atria contract with a rate of almost exactly 300 bpm and commonly there is a 2:1 block. Hence one should always consider atrial flutter in a narrow complex tachycardia with a rate of 150 bpm

Note that, in the context of long term management of atrial flutter, NICE state the management is as for atrial fibrillation:

• "This guideline covers diagnosing and managing atrial fibrillation in adults. It includes guidance on providing the best care and treatment for people with atrial fibrillation, including assessing and managing risks of stroke and bleeding."

Reference:

1. NICE. Atrial fibrillation: diagnosis and management. NICE guideline NG196. Published April 2021, last updated June 2021