RESUMO
Aim To assess the value of the administration of adenosine-5'-triphosphate (ATP) during sinus rhythm for noninvasive diagnosis of AV node dual pathways(AVNDP) and abolition or modification of the slow pathway (SP) after radiofrequency(RFCA) in patients with inducible sustained AVNRT. Methods Incremental doses of ATP were intravenously administrated during sinus rhythm to patients with spontaneous or inducible sustained AVNRT(study group, n=45)and to patients with no evidence of AVNDP or inducible AVNRT (control group, n=37) until ECG signs of AVNDP( 50 ms increase or decrease in P-R interval in two consecutive beats, or occurrence of AVNRT) or second-degree AV block were observed. Results Four patients (two in study patients and two in control patients) could not complete the trial and were excluded from analysis. AVNDP was observed by ATP in 36(84%) study patients, whereas it was diagnosed by electrophysiology criteria in 38(88%) patients. AVNDP was observed only in 1(3%) control patient. AVNDP by ATP test was disappeared in 18(90%) of 20 patients who underwent SP abolition and in 3(38%) of 8 patients who underwent SP modification. Conclusion ATP test during sinus rhythm enables noninvasive diagnosis of AVNDP in a high percentage of patients with inducible AVNRT and reliably confirms the results of RFCA of the SP.