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'-triphosphate (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 antegrade 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 (> or = 50 msec increase or decrease in AH or PR interval in two consecutive beats) or > or = 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.