Atrial flutter most commonly presents with 2:1 block, which means atrial rate of 300 but ventricular rate of 150. Ischaemic chest pain may occur due to the tachycardia. Carotid sinus massage can sometimes terminate or slow the tachycardia.

DC cardioversion should be performed if the patient is cardivascularly unstable. Atrial flutter is commoner in patients with dilated left atrium or in congenital/structural heart disease