Noninvasive diagnosis of dual AV nodal physiology in patients with AV nodal reentrant tachycardia by adenosine triphosphate test

Atrioventricular nodal reentrant tachycardia (AVNRT) is a relatively common paroxysmal supraventricular tachycardia. This Study investigated whether adenosine-5'-triphos-phate (ATP) injection during Sinus rhythm might be useful in the noninvasive diagnosis of dual AV nodal pathways. The study group consisted of 9 patients with slow/fast AVNRT and 11 control patients without antearade dual AV nodal physiology (DAVNP). ATP (2.5 to 30 mg, in 2.5-mg increments) was injected during sinus rhythm until signs of DAVNP (greater than or equal to 50 msec increase or decrease in AH or PR interval in two consecutive beats) or greater than or equal to second-degree AV block was observed. DAVNP was diagnosed by ATP test in all 9 patients with slow/fast AVNRT. DAVNP was observed by ATP test in 3 of the 11 control patients. Thus, the test had a sensitivity of 100% and specificity of 73%. ATP test given during sinus rhythm is useful for identifying patients with dual AV nodal pathways who are prone to AVNRT.