Scintigraphic recognition of papillary muscles and papillary muscle ischemia.

During stress thallium imaging, papillary muscles (anterolateral and posteromedial) appear scintigraphically as focal regions of enhanced activity in sites corresponding to their anatomic position. In the normal case, enhancement after exercise is greater than or equal to enhancement at rest. With papillary muscle ischemia, the involved papillary muscle demonstrates more enhanced activity at rest than at postexercise. This pattern change with papillary muscle ischemia was observed in four patients. Three cases demonstrated complete reversal of those ischemic changes after angioplasty and the remaining case failed to show any significant improvement after angioplasty.