Assessment of Myocardial Perfusion in Patients Afterthe ArterialSwitch Operation

In 21 patients who had undergone the arterial switch operation, theadequacy of myocardial perfusion waseval uatedbythallium-201 computed scintigraphy 2.6±2(0.3— 7) yr after surgery. Fourteen patients had undergone the arterial switch procedureafter pulmonaryartery banding and sevenas a primaryrepair.Isoproterenol stressin creasedthe heart rate by at least 55%. Tomographic imaging wasperformed at peakstressand3 hrlaterinthe reperfusion phase. Nine patients had perfusion defects. The perfusion defectswere locatedat the left ventricular apexinfour(withextension to theinferolateral wallinone), leftventricular anterolateral wallintwo,ventricular septum in one, left ventricularinferiorwall in one, and right ventric ularfreewallin one.Someof thesedefectscouldbedue to myocardial damageat the time of surgery,but these results also raise concern about long-term adequacy of myocardialperfusion following the arterial switch proce dure. J NucIMed 1991;32:237—241