Time course of regional flow distribution following reperfusion of the isolated ischaemic rat heart.

Abstract

1. The regional distribution of flow was studied at different times after the onset of reperfusion in isolated rat heart preparations. The hearts were submitted to 30 min of global ischaemia followed by 60 min of reperfusion. Microspheres labelled with various nuclides were added to the perfusate before ischaemia and 1, 5, 20, and 60 min after the onset of reperfusion. 2. One minute after the start of reperfusion, the flow to the left ventricular inner layer was restricted to 0.5 +/- 0.2 mL/min per g (2-3% of the pre-ischaemic flow). In this segment, the perfusion remained at the same low level during the entire reperfusion period studied. At the onset of reperfusion the flow to the outer layer of the left ventricle was 4.8 +/- 1.7 mL/min per g (37% of the pre-ischaemic flow), and 3.0 +/- 1.3 mL/min per g (27% of the pre-ischaemic value) to the free wall of the right ventricle. The flow was progressively reduced in the outer layer of the left ventricle in the course of reperfusion. After 60 min of reperfusion the flow to the left ventricular outer layer was 2.5 +/- 0.9 mL/min per g (19% of pre-ischaemic flow when compared with the onset of reperfusion [P less than 0.05]). 3. It is concluded that a 'no-reflow' condition develops very early during reperfusion and becomes more marked during this period.