Adenosine and Atrial Tachycardia

Atrial tachycardia (AT) may be encountered in a variety of settings in the electrophysiology laboratory. It constitutes a differential diagnosis in patients presenting for an electrophysiological evaluation and ablation for paroxysmal supraventricular tachycardia. These patients typically do not have any evidence of structural heart disease. Patients may also present with AT in setting of an atrial myopathic process, related to acquired (eg, rheumatic heart disease) or congenital heart disease, cardiac surgery, or an idiopathic process. Finally, patients with atrial fibrillation (AF), especially the persistent variety, often require repeat procedures for organized ATs. Although the prevalence of precise arrhythmia mechanism differs in these contexts, broadly speaking, there are 2 possibilities: focal activation and macroreentry. Focal arrhythmias may be further characterized as being caused by abnormal automaticity, triggered activity, or microreentry/localized reentry.