Effects of myocardial ischemia on ventricular compliance. Protective role of hydrocortisone.

The effects of hydrocortisone on left ventricular force-velocity relations, systolic length-tension curves, and diastolic pressure-volume curves (compliance) were determined before and 30 and 60 minutes after a 1 hour period of normothermic ischemic cardioplegia. Five dogs were given no hydrocortisone, 5 dogs 150 mg. per kilogram of hydrocortisone immediately after aortic unclamping, and 5 dogs 150 mg. per kilogram of hydrocortisone 20 minutes before clamping. Thirty minutes after unclamping, there was a 45 per cent decrease in contractility (p less than 0.005). At 60 minutes, there was a significant improvement (p less than 0.025), although a 32 per cent depression persisted. There were no differences among the three groups (p less than 0.05). Dogs not given hydrocortisone before clamping, compliance decreased 18 per cent (p less than 0.05), and in those given hydrocortisone immediately after unclamping, compliance decreased 28 per cent (p less than 0.025). The decreases in compliance in the hydrocortisone-treated dogs were significantly less (p less than 0.05) than the decreases observed in the dogs not given hydrocortisone.