INFLUENCE OF RESIDUAL PERFUSION WITHIN THE INFARCT ZONE ON THE NATURAL-HISTORY OF LEFT-VENTRICULAR DYSFUNCTION AFTER ACUTE MYOCARDIAL-INFARCTION - A MYOCARDIAL CONTRAST ECHOCARDIOGRAPHIC STUDY

Objectives. This study used myocardial contrast echocardiography to in vestigate the extent of residual perfusion within the infarct zone in a select group of patients with recently reperfused myocardial infarct ion and evaluated its influence on the ultimate infarct size. Backgrou nd. Limited information is available on the status of myocardial perfu sion within postischemic dysfunctional segments at predischarge and on its influence on late regional and global functional recovery. Method s. Twenty patients with acute myocardial infarction were selected for the study. Patients met the following inclusion criteria: 1) single ve ssel coronary artery disease; 2) patency of infarct-related artery wit h persistent postischemic dysfunctional segments at predischarge; 3) s table clinical condition up to 6 months after hospital discharge. All selected patients underwent coronary angiography and myocardial contra st echocardiography before hospital discharge and repeated the echocar diographic examination 6 months later. Patients were grouped according to the pattern of contrast enhancement in predischarge dysfunctional segments. Results. In nine patients (group I), the length of segments showing abnormal contraction coincided with that of the contrast defec t segments. In the remaining 11 patients (group II), postischemic dysf unctional segments were partly or completely reperfused. There was no difference between the two groups in asynergic segment length at predi scharge (7.3 +/- 2.5 vs. 7.2 +/- 4.3 cm, p = NS), At follow-up study, asynergic segment length was significantly reduced in group II patient s, whereas no changes were observed in group I patients (from 7.2 +/- 4.3 to 4.7 +/- 3.7 cm, p < 0.005; and from 7.3 +/- 2.5 to 7.5 +/- 2.9 cm, p = NS, respectively). Conclusions. Among patients with a predisch arge patent infarct related artery, further improvement in regional an d global function may be expected during follow-up when residual perfu sion in the infarct zone is present.