Electrophysiology, Cardiology.
and Multifocal Atrial Tachycardia Automatic Atrial Tachycardia (AAT) is caused by an additional pacemaker node, or automatic focus, in the atrial muscle wall, or myocardium. This additional automatic focus causes tachycardia, where its pacing is faster than that of the SA node. Multifocal Atrial