Atrial tachycardia

Atrial tachycardia or ectopic atrial tachycardia (EAT) is a type of atrial arrhythmia in which the heart's electrical impulse comes from ectopic atrial pacemaker, that is to say an abnormal site in the upper chambers of the heart or atria, rather than from the SA node which is the normal site of origin of the heart's electrical activity. Atrial tachycardias can exhibit very regular rates ranging typically from 140–220 bpm. As any other form of tachycardia, the underlying mechanism can be either the rapid discharge of an abnormal focus, the presence of a ring of cardiac tissue that gives rise to a circle movement - reentry - or a triggered rapid rhythm due to other pathological circumstances as would be the case with some drug toxicities - digoxin toxicity.