What occurs during atrial flutter?

During atrial flutter, the atria contract at a rapid rate, typically at a rate of 240 to 340 beats per minute. This rapid contraction occurs due to a reentrant circuit within the atrium, which causes the electrical signals to loop around and stimulate the atria multiple times before allowing the atrioventricular (AV) node to conduct some of these signals down to the ventricles. As a result, the ventricles may also beat at a rapid but variable rate depending on how many atrial impulses are conducted through the AV node, creating an organized but unusually fast rhythm.

This condition is characterized by a distinct "sawtooth" pattern on an electrocardiogram (ECG), referred to as "F-waves" or "flutter waves," which highlights the organized nature of the atrial contractions and differentiates it from more chaotic rhythms like atrial fibrillation where the atrial contractions are disorganized. Understanding the mechanics of atrial flutter is important for providing appropriate treatment or intervention to manage the heart's rhythm and prevent complications.