Cardioplegic arrest in isolated blood-perfused working rat hearts

An isolated working rat heart model designed for function studies after elective cardiac arrest is described. Before and after a cold ischemic period (induced with St. Thomas' cardioplegic solution) of 30 min, hemodynamic and metabolic variables were assessed in a group of 13 hearts perfused with a modified Krebs-Henseleit solution and in a group of 13 hearts perfused with reconstituted blood. Functional recovery was about 90% in the nonblood-perfusate group and 98% in the blood-perfused group. Functional deterioration in time due to edema formation and limited oxygenation in electrolyte-perfused hearts was found to be of the same magnitude as the function loss ascribed to deleterious effects of cardioplegic arrest. The blood-perfused hearts showed hemodynamic stability during a 75 min continuous working period, and complete recovery of function after 30 min arrest.