[Typical AV nodal reentry tachycardia in 4 anterograde AV nodal pathways. Successful high frequency ablation of slow AV nodal pathways].

CASE REPORT: A 26-year-old patient was referred to our department for electrophysiologic evaluation of recurrent paroxysmal tachycardias with narrow QRS-complexes (< 120 ms). Three jumps in the AV-nodal conduction curve were detected during programmed atrial extrastimulation in sinus rhythm and at a cycle length of 600 ms indicating of 4 antegrade conducting AV-nodal pathways. After intravenous application of orciprenaline an AV-nodal re-entrant-tachycardia (AVNRT) of the common type was induced with a cycle length of 290 ms. During tachycardia, antegrade conduction occurred via one of the slow conducting pathways, retrograde conduction via the fast pathway ("slow-fast"-AVNRT). Application of radiofrequency energy was able to ablate all slowly conducting AV-nodal pathways at one site in the infero-posterior region of Koch's triangle. During control stimulation with and without orciprenaline no AH-jump or inducible tachycardia was found.

CONCLUSION: This case shows the rare finding of 4 antegrade AV-nodal pathways in a patient with the common type of AVNRT. Application of radiofrequency current was able to ablate all slow conducting AV-nodal pathways successfully.