Alifedrine, a positive inotropic agent that moderately reduces the severity of ischaemia and reperfusion-induced ventricular arrhythmias.
The effects of alifedrine, a positive inotropic agent, were examined in greyhounds anaesthetised with chloralose. An intravenous dose of 0.3 mg kg-1 resulted in a substantial increase in myocardial contractility (increased dP/dtmax, cardiac output and stroke volume) without significantly affecting heart rate. The effects of alifedrine on the severity of arrhythmias resulting from both coronary artery occlusion and reperfusion were also determined. A mild antiarrhythmic effect was observed during early ischaemia when the incidence of ventricular tachycardia was reduced from 90% in controls to 50% in treated dogs. There was also a significant reduction in the number of extrasystoles appearing as ventricular tachycardia (from 511 +/- 138 to 151 +/- 84). The total number of extrasystoles during the first 30 min of ischaemia was also reduced, although not significantly, from 846 +/- 193 to 527 +/- 86. Following release of a 40 min coronary artery occlusion there was a marked reduction in reperfusion-induced ventricular fibrillation from 75% in controls, to 37% in the alifedrine-treated dogs. The overall survival from the combined occlusion-reperfusion insult was increased from 20% in controls to 50%. These results suggest that alifedrine has an unusual and useful spectrum of pharmacological activity in that it combines antiarrhythmic activity with an ability to improve cardiac function.
Wainwright
C L
CL
Department of Physiology and Pharmacology, University of Strathclyde, Glasgow, U.K.
Parratt
J R
JR
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D002316:Cardiotonic Agents / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects; D003327:Coronary Disease / Q000188:drug therapy* / Q000503:physiopathology; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D010099:Oxyfedrine / Q000031:analogs & derivatives / Q000494:pharmacology*; D011427:Propiophenones / Q000494:pharmacology*
D002316:Cardiotonic Agents; D011427:Propiophenones; D010099:Oxyfedrine; C039523:alifedrine