[Idionodal reciprocal tachycardia irresponsive to pharmacological prophylaxis. Description of a case successfully treated with radio frequency].

The case of a 63-year old female suffering from recurrent paroxysmal supraventricular tachycardia for 30 years is reported. In the past she was treated unsuccessfully with multiple drugs. Electrophysiological study showed dual nodal pathways and the inducibility of a junctional reciprocating tachycardia with RR and V-A intervals respectively 360-410 and 40 msec. Radiofrequency was applied for 30" in the nodal region during induced reciprocating tachycardia. The arrhythmia was interrupted after a few seconds and a 1st degree A-V block persisted for a few minutes. Repeated electrophysiological studies were performed 30 minutes and 20 days after the ablating procedure. They showed a slight increase in AH interval from 55 msec to 90 and 65 msec respectively, as well as the persistence of anterograde dual nodal pathways and the disappearance of retrograde conduction of the A-V node. No reentry arrhythmia could be induced. After six months the patient is asymptomatic and drug free.