UNLABELLED: Intravenously administered adenosine triphosphate (ATP) converts some supraventricular tachycardias to a sinus rhythm. Temporary atrioventricular block can help with the differentiation of different forms of supraventricular tachycardia.

METHOD: Twenty-one patients with different forms of supraventricular tachycardia were subjected to electrophysiological examination for diagnostic or therapeutic (ablation) purposes. During tachycardia (after 5 minutes duration) ATP Spofa was administered by the i.v. route within 3 s into the cubital vein--0.3 mg per 1 kg body weight.

RESULTS: One patient had two forms of supraventricular tachycardia. In the first group with auricular fibrillation (AF, n = 10), with auricular flutter (AFL, n = 5) and with automatic auricular tachycardia (AAT, n = 1) tachycardia was not eliminated by intravenously administered ATP. In the second group the authors were always able to eliminate paroxysmal supraventricular tachycardia, AV nodal reciprocal (AVNRT, n = 4) and atrioventricular reciprocal tachycardia (AVRT, n = 2) by intravenously administered ATP.

CONCLUSIONS: 1. The authors conclude that ATP exerts an antiarrhythmic effect by blocking the reentry circuit in the AV node, i.e. it converts reentry supraventricular tachycardias (AVNRT and AVRT) to a sinus rhythm after reciprocal atrial activity. 2. The effect on atria can be proarythmogenic. 3. The authors did not confirm the effect on abnormal automaticity.