Dr. Shariati Hospital, North Kargar Ave. Tehran, Iran
Background- In the typical or common form of atrioventricular nodal reentrant tachycardia (AVNRT) the anterograde limb of the reentrant circuit is a relatively slowly conducting pathway (the slow pathway) and the retrograde limb is a relatively rapidly conducting pathway (the fast pathway). In the atypical form of (AVNRT), anterograde conduction is via the fast pathway and retrograde conduction is via the slow pathway and it is associated with a long R-P interval.
Methods and Results- Among 133 Iranian patients with frequent episodes of AVNRT, which was documented by electrophysiologic study and radiofrequency (RF) catheter ablative therapy, only one patient had atypical form of AVNRT; thus the incidence was 0.75% in our patients. Slow pathway ablation was performed on our patient with atypical form of AVNRT without any complications. In 3 years of follow-up, the patient was free of arrhythmia without any anti-arrhythmic drugs.
Conclusions- This study demonstrates that the incidence of atypical AVNRT in our patients was less than proviously reported srudies.