Action of ATP on ventricular automaticity.
ATP is an effective treatment of supraventricular tachycardia when the atrioventricular (AV) node is part of the reentrant circuit. However, the lower a pace-maker in the pacemaker hierarchy, the more sensitive it is to adenosine. Therefore, we investigated the effects of ATP on ventricular automaticity in in vivo and in vitro conditions. Wide and narrow QRS complex tachycardia in 46 patients was treated with 6, 12, and 18 mg ATP as sequential intravenous (i.v.) bolus. ATP terminated tachycardias in 67%. Bolus infusion ATP caused < or = 6.4-s asystole that was self-limited. Perfusion of isolated spontaneously beating guinea pig heart with 100 microM ATP completely suppressed ventricular automaticity. After ATP-infusion was discontinued, the first ventricular beat was evident after 3.1 +/- 0.9 s and sinus node activity recovered with a time constant of 3.0 +/- 1.1 s. Because sinus node and ventricular automaticity recovered within seconds after ATP infusion was discontinued in vitro, recovery in vivo is also likely to be determined by the short half-life (+1/2) of ATP.
Stark
G
G
Department of Internal Medicine, Karl-Franzens-University, Graz, Austria.
Domanowits
H
H
Sterz
F
F
Stark
U
U
Bachernegg
M
M
Kickenweiz
E
E
Decrinis
M
M
Laggner
A N
AN
Tritthart
H A
HA
D000255:Adenosine Triphosphate / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D000404:Ajmaline / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001317:Austria; D002304:Cardiac Pacing, Artificial; D004347:Drug Interactions; D004632:Emergency Medical Services; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D011405:Propafenone / Q000494:pharmacology / Q000627:therapeutic use; D011446:Prospective Studies; D011802:Quinidine / Q000494:pharmacology / Q000627:therapeutic use; D013617:Tachycardia, Supraventricular / Q000188:drug therapy*; D016276:Ventricular Function / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology / Q000627:therapeutic use
D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D000404:Ajmaline; D011405:Propafenone; D000255:Adenosine Triphosphate; D014700:Verapamil; D011802:Quinidine