Diagram Comparing Normal Heart Function

On the left, the illustration shows the normal electrical pathways and normal rhythm in the heart. On the right, the illustration shows an asterisk in the left atrium and an arrow in the right atrium, where two types of tachycardia may originate in the atria. The panels beneath are typical ECG recordings of a heart with a normal heart rhythm (left) and a heart with atrial tachycardia (right).