Atrial Flutter

Atrial flutter is 8 times rarer than atrial fibrillation, but increases to approximately 15 times in elderly patients. The arrhythmia may last for several beats, several minutes, hours, months, or even years. Symptoms preferentially depend on ventricular rate, which is determined by atrioventricular conduction. The etiology of atrial flutter is as manifold as that of atrial fibrillation.

The (atrial) rate of atrial flutter is between 230 and 330 beats/min, often between 260 and 300 beats/min, and is stable in an individual patient. Atrial impulses are frequently blocked within the atrioventricular (AV) node in a 2:1 mode (2:1 AV block), resulting in a ventricular rate of approximately 130–150 beats/min. Atrial rate is slowed by a dilated right atrium and an excessive intraatrial conduction disturbance. Drugs such as amiodarone will decrease the rate to less than 200 beats/min. Preexisting or rate-dependent right bundle-branch block (or rarely left bundle-branch block) might be present, masking the flutter waves and mimicking ventricular tachycardia at a first glance. A tachycardia with small or broad QRS, especially with right bundle-branch block configuration, at a rate of 130–160 beats/min, represents atrial flutter in approximately 70% of the cases (ECG 20.1).