Administration of
adenosine triphosphate (
ATP) in sinus rhythm identifies dual atrioventricular node physiology (DAVNP) in 75% of patients with inducible slow/fast
AV nodal reentrant tachycardia (AVNRT). The incidence of DAVNP following termination of AVNRT with
ATP is unknown. Incremental doses of
ATP (10-60 mg) were administered, first in sinus rhythm and then during
tachycardia induced at electrophysiologic study, to 84 patients with inducible AVNRT and to 18 control patients with inducible AV reentrant
tachycardia (AVRT) and no electrophysiologic evidence of DAVNP. Study end-points were the occurrence of DAVNP or > or = 2nd degree
AV block following administration of
ATP in sinus rhythm and
tachycardia termination following administration of
ATP during
tachycardia. Of the 82 patients with AVNRT who completed the study, 62 (75.6%) exhibited DAVNP following administration of 17.1 +/- 9.4 mg
ATP in sinus rhythm, while 30 (36.5%) exhibited DAVNP at the termination of AVNRT following administration of 10.6 +/- 2.4 mg
ATP. The occurrence of DAVNP following the administration of 10 mg
ATP in sinus rhythm.was a good predictor (62%) of its occurrence after termination of AVNRT with
ATP. The dose of
ATP had a strong correlation between the presence of DAVNP following AVNRT termination and the
ATP doses needed for
tachycardia termination. Of the 18 control patients, none had DAVNP at
ATP test during sinus rhythm but 1 (5.5%) showed slight (60 msec) PR jump after termination of AVRT with
ATP. In conclusion, DAVNP is present in a relatively high proportion (36.5%) of patients following termination of AVNRT with
ATP but is much less frequent (5.5%) in control patients. Thus, findings at termination of
tachycardia by
ATP may be useful in the noninvasive diagnosis of the mechanism of a
paroxysmal supraventricular tachycardia.