[Induction of atrial fibrillation by adenosine in a patient with supraventricular tachycardia].

Adenosine is generally considered to be safe and effective in treatment of orthodromic circus movement tachycardia in patients with accessory pathways. We present a case with reproducible induction of atrial fibrillation after initial successful termination of orthodromic circus movement tachycardia using a left sided accessory pathway by adenosine. With the induction of atrial fibrillation sudden onset of preexcitation with subsequent rapid ventricular response was accompanied by moderate hemodynamic compromise. Before and after successful ablation of the accessory pathway, adenosine was not able to induce atrial fibrillation when applied during sinus rhythm. Adenosine induced atrial fibrillation is due to shortening of the atrial action potential duration and atrial refractoriness, whereas shortening of the antegrade refractory period in the accessory pathway leads to rapid conduction to the ventricles. Thus, care should be taken using adenosine in patients with orthodromic circus movement tachycardias and evidence of antegrade preexcitation during sinus rhythm.