Importance of gated imaging in both phases of myocardial perfusion SPECT: myocardial stunning after dipyridamole infusion.

We present the case report of a 72-y-old woman who underwent (99m)Tc-sestamibi gated myocardial perfusion SPECT with a 2-d protocol. SPECT images revealed ischemia of the apical, anteroapical, apicoseptal, and septal walls. Postdipyridamole gated SPECT revealed significant deterioration in the left ventricular ejection fraction (LVEF), wall motion, and systolic wall thickening relative to the findings obtained with rest gated SPECT. Myocardial stunning is a lingering contractile dysfunction that occurs after a brief ischemic insult. Myocardial stunning after dynamic exercise or pharmacologic stress tests has been demonstrated. Thus, the use of gated SPECT in both phases of perfusion studies may add useful information about cardiac function, as a poststress study alone probably reflects stunned myocardium in some patients undergoing ischemic stress tests. The difference between poststress LVEF and rest LVEF may have a powerful impact on prognosis, as it seems to depend on the extent and severity of induced ischemia.