ULTRASTRUCTURAL ASSESSMENT OF THE MYOCARDIUM RECEIVING INTERMITTENT ANTEGRADE WARM BLOOD CARDIOPLEGIA

Ultrastructural changes in the myocardium during intermittent warm blo od cardioplegia were studied in 12 dogs, During cardiopulmonary bypass , dogs received three S-minute periods of warm blood cardioplegia, int errupted by three 10-minute episodes of ischemia in group A or three 2 0-minute episodes of ischemia in group B, Biopsy specimens were taken from the right ventricle before each cardioplegic infusion and at the end of the aortic cross-clamp period to analyze ultrastructural change s. Functional recovery was measured after cardiopulmonary bypass. Mild and principally reversible ultrastructural changes were observed in g roup A. In group B, moderate ultrastructural changes were observed, an d these changes suggested cumulative ischemic injury. Functional recov ery was good in group A, but significantly deteriorated in group B. We concluded that three 10-minute interruptions of warm blood cardiopleg ia cause mild ultrastructural changes and seem to be safe, but three 2 0-minute interruptions cause cumulative ischemic injury in normal dog hearts. (C) 1998 The International Society for Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights reserved.