[The diagnostic and therapeutic usefulness of adenosine triphosphate in supraventricular tachycardias].

The efficacy and safety of intravenous adenosine-5'-triphosphate (ATP) in supraventricular tachycardia (SVT) were investigated in 40 patients, aged 1 month-69 years (mean 28 years). Thirty-one had a history of paroxysmal supraventricular tachycardia (group A), 9 had chronic supraventricular tachycardia (group B). Four patients in Group A had long R-P' tachycardia. In group A, transesophageal atrial pacing was utilized for tachycardia induction. A ventriculoatrial interval (VA) during tachycardia greater than 70 ms was considered diagnostic for reentry by an AV accessory pathway (AP), while a VA less than or equal to 70 ms suggested reentry within the AV node. Serial rapid intravenous injections of graded doses of ATP were performed in both groups. In 14 patients of group A, graded doses of ATP (0.075, 0.1, 0.125, 0.15, 0.2, mg/kg) were performed in order to analyze the dose-response relationships. In group A, ATP resulted in termination of tachycardia in all patients (21 with reentry by an AP, 10 with intranodal reentry). A total of 77 tachycardia episodes were interrupted. A 100% efficacy was found with doses of greater than or equal to 0.15 mg/kg of ATP. Among patients with AP reentry, interruption in the anterograde limb of the reentry circuit occurred in 16 patients, while termination of tachycardia after retrograde block was observed in 5 patients, 4 of whom with long RP' tachycardia. In group B, ATP resulted in transient 2:1 or high degree AV block in 8 patients. Transient restoration of sinus rhythm was observed in 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)