Atrial tachycardia is an arrhythmia with electrical impulses originating within the atria. Atrial tachycardia can be a result of one or a combination of the mechanisms leading to arrhythmia: automatic, triggered activity, or reentry. In some cases, the mechanism remains undetermined. Electrophysiologic features may overlap if there is a small reentrant circuit, as in micro-reentry. It is useful to categorize atrial tachycardia in two broad groups: macroreentrant or focal.
The prototypic macroreentrant atrial tachycardia is an atrial flutter. Typical atrial flutter arises from the right atrium in a circuit bound anteriorly by the tricuspid annulus and posteriorly by the crista terminalis and Eustachian ridge. The electrical activity can travel in a clockwise or counterclockwise direction in this circuit.
Atrial flutter is a complex arrhythmia with different management than focal atrial tachycardias. As such, the focus of this activity will be on focal atrial tachycardia (FAT).
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