The influence of pressure controlled reperfusion on the postischemic outcome of normal and normotensive hypertrophied rat hearts should be investigated. To induce normotensive cardiac hypertrophy, male Wistar rats received injections of isoprenaline (5 mg/kg s.c. bid for three days). Hearts were excised and perfused according to the Langendorff-technique at a perfusion pressure of 75 mm Hg for 30 min. After cardioplegia and 40 min of global ischemia at 25 degrees C the hearts were reperfuse for 45 min. Reperfusion pressure was increased either abruptly (75 mm Hg immediately) or gradually (from 40 mm Hg to 75 mm Hg within 30 min). Post-ischemic recovery was significantly affected by the mode of reperfusion in normal hearts, in which pressure controlled (gradual) reperfusion was superior to the abrupt reperfusion mode. In hypertrophied hearts, the post-ischemic outcome did not differ from normal hearts when abrupt reperfusion was used, but gradual reperfusion only led to a comparably small improvement of the post-ischemic status.