Time course of myocardial viability after acute myocardial infarction: an echocardiographic study

The recognition of dysfunctional but viable myocardium after acute myocardial infarction (MI) may be of importance for both patient prognostication and the decision for revascularization. Low-dose dobutamine echocardiography (LDDE) has been shown to be a reliable technique in detecting reversibility of dysfunctional myocardium. The aim of the present study was to assess by LDDE possible time-dependent changes in myocardial viability and to evaluate the value of LDDE used in the postinfarction period. Twenty-seven patients with acute MI underwent LDDE on day 6, 30, and 90. At LDDE day 6, 41% of the affected segments showed a positive response to LDDE. At later examination on day 30 and 90, only 32% and 18%, respectively, of the dysfunctioning segments responded to dobutamine stimulation, with a significant decline in response (p < 0.0001), indicating loss of viability. Spontaneous segmental outcome was significantly better for LDDE-responding segments than for nonresponding segments (p = 0.0001). This study indicated that myocardial viability may be temporary and that a time-dependent loss of viability may take place during the first months after MI.