[Cardiodepressive effects due to ketamine, etomidate, methohexitone and propanidid. A clinical study by means of the systolic-time-intervals (author's transl)].

The cardiodepressive effects of ketamine (1mg/kg), etomidate (0.3mg/kg), methohexitone (1mg/kg) and propanidid (4mg/kg) have been compared by means of the systolic time intervals on patients during a steady-state halothane--N2O:02(1.1)-- anaesthesia. This anaesthesia served as a pharmacological model of reduced myocardial function, and moreover, it should block the centrally-elicited cardiac stimulation by ketamine, thus unmasking the direct negative inotropic action of this anaesthetic. Ketamine and etomidate are of lesser cardiac depressant action than methohexitone or even propanidid. Diazepam (0.2-0.25mg/kg) proved to be able to attenuate or abolish, respectively, the ketamine-induced increases of heart rate and blood pressure in normo- and hypertensive patients, and might therefore be useful for induction anaesthesia in cardiac and coronary risk patients, as proved on two patients with recent myocardial infarction.