Background: Accessory pathways are muscular connections between auricl
es and ventricles, present in different points of mitral and tricuspid
annuluses. These pathways participate in 50% of paroxysmal supraventr
icular tachycardias and the definitive cure of the arrhythmia is their
ablation. Aim: To report our experience in patients with right access
ory pathways. Patients and methods: Fifty consecutive patients treated
between 1990 and 1996 are reported. Eight had a history of syncope, t
wo had a diagnosis of Ebstein disease and 36 had a pre-excitation in t
he surface electrocardiogram. Results: Fifty four accessory pathways w
ere identified, since four patients had two pathways. Twenty four path
ways were posteroseptal, 15 were lateral, 9 were medioseptal and 6 wer
e anteroseptal. One patient had also a nodal reentry tachycardia. Fulg
uration was attempted in 39 patients and it was finally successful in
32. Three patients required more than one session. There were six rela
pses and all were successfully ablated in a second session. A mean of
28 radiofrequency applications were done (range 1-76), mean laboratory
time was 6 hours and mean radioscopy time was 70 min. Four patients h
ad a transient atrioventricular conduction blockade. Conclusions: Radi
ofrequency ablation of accessory pathways has a high degree of success
and a low rate of complications.