ADENOSINE-SENSITIVE BUNDLE-BRANCH REENTRY

Adenosine-Sensitive Bundle Branch Reentry, Introduction: Bundle branch reentry is an uncommon mechanism for ventricular tachycardia. More in frequently, both fascicles of the left bundle may provide the substrat e for such macroreentrant bundle branch circuits, so-called interfasci cular reentry, The effect of adenosine on bundle branch reentrant mech anisms of tachycardia is unknown. Methods and Results: A 59-year-old m an with no apparent structural heart disease and history of frequent s ymptomatic wide complex tachycardias was referred to our center for fu rther electrophysiologic evaluation, During electrophysiologic study, a similar tachycardia was reproducibly initiated only during isoproter enol infusion, which had the characteristics of bundle branch reentry, possibly using a left interfascicular mechanism, Intravenous adenosin e reproducibly terminated the tachycardia, Application of radiofrequen cy energy to the breakout site from the left posterior fascicle preven ted subsequent tachycardia induction and rendered the patient free of spontaneous tachycardia during long-term follow-up, Conclusions: Patie nts with ventricular tachycardia involving a bundle branch reentrant c ircuit may be sensitive to adenosine, These results suggest that adeno sine may not only inhibit catecholamine-mediated triggered activity bu t also some catecholamine-mediated reentrant ventricular arrhythmias.