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

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-1.100g-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 less than 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 50 cm3. min-1. 100g-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.