title: Effects of OPC-8212, a new positive inotropic agent, on canine ventricular arrhythmias.
abstract: OPC-8212, a positive inotropic agent that increases intracellular cyclic AMP and stimulates the Ca current, was compared with amrinone and AR-L 115 in their effects on canine ventricular arrhythmias. OPC-8212, up to 3 mg kg-1, did not worsen 24 h coronary ligation arrhythmias, while it aggravated ventricular arrhythmias seen 48 h after coronary ligation. However, OPC-8212 did not at any time induce ventricular fibrillation in dogs subjected to coronary ligation. OPC-8212, up to 3 mg kg-1, had no arrhythmogenic or antiarrhythmic effect on digitalis-induced arrhythmias, while amrinone and AR-L 115 showed antiarrhythmic effects. With adrenaline-induced arrhythmias, the three drugs aggravated ventricular tachycardia to produce ventricular fibrillation. The absence of a worsening effect of the new positive inotropic agents on digitalis arrhythmia may be helpful in clinical setting of combined therapy of these new drugs with digitalis.
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000188:drug therapy*; D004071:Digitalis Glycosides / Q000627:therapeutic use; D004285:Dogs; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006352:Heart Ventricles; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D011719:Pyrazines; D011804:Quinolines / Q000627:therapeutic use*; D013268:Stimulation, Chemical; D013997:Time Factors
chemical_list: D004071:Digitalis Glycosides; D011719:Pyrazines; D011804:Quinolines; C041667:vesnarinone; D004837:Epinephrine