Underestimation of residual ischemia by 201-thallium scintigraphy after myocardial infarction.

Pre- and post-CABG perfusion scintigraphic findings are reported in a patient with residual ischemia after anterior myocardial infarction. The preoperative 201Tl scan showed incomplete tracer redistribution and a relevant area of persistent irreversible defect, suggestive of a large scar. After CABG, the presence of a virtually normal early thallium distribution demonstrated previous underestimation of the viable perinecrotic tissue. A persistent perfusion defect, even if associated with wall motion abnormality, does not necessarily imply the absence of residual viable tissue.