Time-course of dobutamine-induced wall motion abnormalities in the infarct area following thrombolytic therapy

Stress-induced asynergies in the infarct area following thrombolytic therapy are considered to reflect incomplete recanalization of the culprit vessel. However, reperfusion is a dynamic process with successive pathophysiological phases, so that the timing of assessment of residual ischemia may have relevant clinical implications. We studied the time-course of dobutamine-induced homozonal asynergies in 61 (group B) survivors of uncomplicated infarction as compared to 54 (group A) control subjects showing normal response to dobutamine stress echocardiography within 10 days of acute myocardial infarction. The 79 (43 of group A and 36 of group B) patients not presenting new cardiac events underwent further dobutamine stress echo within 90 +/- 17 days, which was positive in 20 and negative in 59. Persistence of test positivity was observed in just 17/36 (47%) patients, who showed significantly more extensive dobutamine-induced asynergies as compared to pre-discharge evaluation and less frequent (p < 0.01) evidence of viable myocardium. These results arise question about the decisional impact of stress-induced wall motion abnormalities in the culprit vessel area early after thrombolysis in low-risk patients and emphasize the need to further clarify the time factor role in this setting.