Author + information
- Received June 2, 1986
- Revision received September 10, 1986
- Accepted October 10, 1986
- Published online March 1, 1987.
- ↵*Address for reprints: George A. Beller, MD, Cardiology Division, Box 158, University of Virginia Medical Center. Charlottesville, Virginia 22908.
Myocardial thallium-201 scintigraphy is being increasingly employed as a method for assessing the efficacy of coronary reperfusion in acute myocardial infarction. New thallium uptake after intracoronary tracer administration after successful recanalization indicates that nutrient blood flow has been successfully restored, One may also presume that some myocardial salvage occurred if thallium administered in this manner is transported intracellularly by myocytes with intact sarcolemmal membranes. However, if one injects thallium by way of the intracoronary route immediately after reperfusion, the initial uptake of thallium in reperfused myocardium may predominantly represent hyperemic flow and regional thallium counts measured may not be proportional to the mass of viable myocytes. When thallium is injected intravenously during the occlusion phase the degree of redistribution after thrombolysis is proportional to the degree of flow restoration and myocardial viability. When thallium is injected for the first time intravenously immediately after reperfusion, an overestimation of myo- cardial salvage may occur because of “excess” thallium uptake in the infarct zone consequent to significant hyperemia. Another approach to myocardial thallium scintigraphy in patients undergoing thrombolytic therapy is to administer two separate intravenous injections before and 24 hours or later after treatment. Clinical studies have demonstrated that the improvement in defect size on serial images predicts improvement in regional function and patency of the infarct-related vessel.
Finally, patients with acute myocardial infarction who receive intravenous thrombolytic therapy are candidates for predischarge exercise thallium-201 scintigraphy for risk stratification and detection of residual ischemia. Patients demonstrating thallium redistribution in the zone of the infarct-related vessel or multiple defects within or remote from the infarct region would be candidates for revascularization to reduce the incidence of subsequent ischemic events.
↵1 From the Cardiology Division, Department of Internal Medicine, University of Virginia Medical Center, Charlottesville, Virginia.
* Part I and II of this Seminar appeared in the November 1986 and January 1987 issues of the Journal.
- Received June 2, 1986.
- Revision received September 10, 1986.
- Accepted October 10, 1986.
- American College of Cardiology Foundation