Atrial tachycardia: Mechanisms and management
Atrial tachycardias comprise a heterogeneous group of arrhythmias that include focal atrial tachycardia, typical atrial flutter and atypical atrial flutter. Focal atrial tachyardias arise from automatic, triggered or microreentrant mechanisms, while typical and atypical flutters are macroreentrant in nature. Typical flutter describes a reentrant circuit that is dependent on the cavotricuspid isthmus in the right atrium while atypical flutter includes various lesional and de novo macroreentrant circuits in the right and left atria. Electrocardiographic criteria have been proposed to distinguish these mechanisms of tachycardia, but they are not specific; whereas adenosine often aids in the diagnosis. Management of focal atrial tachyardias and macroreentry centers around rate control, antiarrhythmic therapy, ablation and anticoagulation. Success rates for ablation are highest for typical atrial flutter and higher than antiarrhythmic therapy for most atrial tachycardias.