[The action of oxyfedrine on haemodynamics, inotropism and blood perfusion of the partially ischaemic myocardium after digoxin premedication. Studies on anaesthetized dogs (author's transl)].

The effect exerted on the partially ischaemic heart when administering 0.9 mg/kg L-3-(beta-hydroxy-alpha-methylphenethylamino)-3'-methoxypropiophenone (oxyfedrine, ildamen) approx. 10 min after i.v. application of 0.05 mg/kg digoxin was tested on 20 dogs previously anaesthetized with propiomazine-pentobarbital. The following parameters were studied and subsequently compound with the results of former trials of ours' without digoxin premedication: aortic pressure (ASP, ADP), left-ventricular pressure (LVSP, LVEDP), heart rate (HR), cardiac output (HMV), stroke volume (SV), dp/dtmax, dp/dtmax/IP, t-dp/dtmax, blood flow in the normal and partially ischaemic myocardium, the latter being measured with heat conductance probes and labelled microspheres. ASP and ADP show the same reduction--as compared with the control value--both after the administration of oxyfedrine with and without digoxin premedication. After digoxin premedication oxyfedrine led to a somewhat less marked reduction of LVSP; on premedication with digoxin LVEDP was slightly increased whereas it was reduced after additional administration of oxyfedrine as was also the case without digoxin pretreatment. The increase in HR after oxyfedrine is almost the same as without digoxin pretreatment. Also the increase in HMV and the SV lowering are not influenced by digoxin. By administration of oxyfedrine dp/dtmax is always increased by the same amount, starting from the already increased value after digoxin premedication, which is probably an additive effect. The same applies to the quotient dp/dtmax/IP. After oxyfedrine the time t-dp/dtmax is lowered by the same amount, irrespective of a digoxin premedication. Oxyfedrine does not produce a further increase in the heat conductance values after previous application of digoxin; when measuring the blood flow with labelled microspheres the same result was found, which means that by previous administration of digoxin the circulatory effect of oxyfedrine is obviously inhibited. Summing up one can say that by combining the active principles digoxin and oxyfedrine the function parameters of the heart can be influenced only positively.