Atrial flutter is less common but has similar symptoms to AF. It differs in that the atria contract regularly but typically at around 300 bpm, with the atria contracting up to four times as frequently as the ventricles, straining the heart. This can increase blood clot (thrombus) risk in the ventricles, leading to a stroke.8
Around one third of patients with atrial flutter have atrial fibrillation, with the heart switching between periods of AF and atrial flutter.