DOES THE MYOCARDIUM BECOME STUNNED AFTER EPISODES OF ANGINA AT REST, ANGINA ON EFFORT, AND CORONARY ANGIOPLASTY

To assess whether myocardial stunning occurs after brief periods of is chemia, global and regional ventricular function assessed by radionucl ide angiography was studied in 52 patients. Patients were divided into 3 groups according to the type of ischemic episodes. Group 1 consiste d of 15 patients studied before, during and after episodes of angina a t rest. Seventeen patients studied immediately before and after corona ry angioplasty constituted group 2. Group 3 consisted of 20 patients w ith stable angina studied before, during and after exercise-induced is chemia. Medical therapy was discontinued 48 hours before the study in all patients except those undergoing coronary angioplasty who were rec eiving diltiazem 180 mg/day. No difference in baseline ejection fracti on was found between groups, whereas peak filling rate was statistical ly lower in group 3 patients. Evidence of left ventricular dysfunction during ischemia was seen in patients in groups 1 and 3, whereas trans ient ischemia was documented by ST-segment displacement and/or typical chest pain during balloon inflation in group 2. Persistence of systol ic or diastolic dysfunction was not observed in any of the 3 groups in the recovery phase after ischemia. In conclusion, transient ischemia caused either by a primary reduction in oxygen supply (angina at rest, coronary angioplasty) or by an increase in oxygen demand (angina on e ffort) did not reproduce the phenomenon of systolic and diastolic stun ning observed in animal experiments, although in all patients the isch emia was of sufficient duration and severity to induce marked ventricu lar dysfunction. The search for stunned myocardium should be extended to other different clinical models characterized by prolonged ischemia such as unstable angina or myocardial infarction.