CLINICAL AND ELECTROPHYSIOLOGIC CHARACTERISTICS AND LONG-TERM EFFICACY OF SLOW-PATHWAY CATHETER ABLATION IN PATIENTS WITH SPONTANEOUS SUPRAVENTRICULAR TACHYCARDIA AND DUAL ATRIOVENTRICULAR NODE PATHWAYS WITHOUT INDUCIBLE TACHYCARDIA

Objectives. We sought to investigate the long-term efficacy of slow-pa thway catheter ablation in patients with spontaneous, documented parox ysmal supraventricular tachycardia (PSVT) and dual atrioventricular (A V) node pathways but without inducible tachycardia. Background. The la ck of reproduction of clinical PSVT by programmed electrical stimulati on, which is not uncommon in AV node reentrant tachycardia (AVNRT), is a dilemma in making the decision of the therapeutic end point of radi ofrequency catheter ablation. Methods. Twenty-seven patients (group A) with documented but noninducible PSVT and with dual AV node pathways were prospectively studied. Programmed electrical stimulation could in duce a single AV node echo beat in 12 patients, double echo beats in 4 patients and none in 11 patients at baseline or during isoproterenol infusion. Of the patients in group A, 16 underwent slow-pathway cathet er ablation and II did not. The clinical and electrophysiologic charac teristics of the 27 patients were compared with those of patients with dual AV node pathways and inducible AVNRT (group B, n = 55) and patie nts with dual AV node pathways;alone without clinical PSVT (group C, n = 47). Results. During 23 +/- 13 months of follow-up, none of the 16 patients with slow-pathway catheter ablation had recurrence of PSVT. H owever, 7 of the 11 patients without ablation had PSVT recurrence at 1 3 +/- 14 months of follow-up (p < 0.03 by Kaplan Meier analysis). Comp ared with groups B and C, group A consisted predominantly of men who h ad better retrograde AV node conduction and a narrower zone for antero grade slow-pathway conduction. Conclusions. Slow-pathway catheter abla tion is highly effective in eliminating spontaneous PSVT in which the tachycardia is not inducible despite the presence of dual AV node path ways. (C) 1998 by the American College of Cardiology.