Myocardial depression by ketamine. Haemodynamic and metabolic observations in animals

This study investigated the effect of ketamine on myocardial function. In dogs the drug was infused directly into the left main coronary artery. The concentration chosen was similar to the peak concentration found following a bolus intravenous injection. A mild depression of inotropic state was found which recovered completely after stopping the infusion. Myocardial depression was confirmed in a guinea pig Langendorff preparation. No changes in high energy phosphates were found in these hearts after 45-60 minutes of perfusion with ketamine in the perfusion medium. This study confirms that myocardial depression occurs with ketamine but suggests that it is unlikely to be of clinical significance. Depletion of high energy phosphates did not seem to be the cause of the depression.