A method for demonstrating the efficacy of interventions designed to limit infarct size following coronary occlusion: Beneficial effect of hyaluronidase

Summary: In order to measure the protective effect of interventions following coronary artery occlusions in dogs, the creatine kinase activity of myocardial tissue was assayed after 24 h and related to the myocardial blood flow of that tissue measured with ⁸⁵Sr labelled microspheres injected 15 min after occlusion. This assay showed normal levels when flow exceeded 50 cm³·min^-1·100 g^-1. In myocardium with flow reduced to 0 to 15 cm³·min^-1·100 g^-1, creatine kinase activity was 7.6 ± 0.6 IU·mg^-1 protein in control dogs and 13.1 ± 1.8 IU·mg^-1 protein (P<0.01) in dogs given 500 NF units·kg^-1 of hyaluronidase 20 min after occlusion. Where myocardial blood flow was reduced to 16 to 50cm³·min^-1·100 g^-1, creatine kinase activity was increased from 14.1 ± 1.1 to 20.5 ± 1.4 IU·mg^-1 protein by hyaluronidase. This method therefore assesses ischaemic damage independent of electrophysiological measurements and confirms myocardial preservation by hyaluronidase.