Progression of HED defects during the development of hibernating myocardium in chronically instrumented pigs. Preserved HED uptake at 1 month confirmed that LAD instrumentation did not affect regional sympathetic nerve function.16 The polar maps at 2 and 3 months after instrumentation were serially obtained in the same animal. These studies show a clear progression from a small, localized defect in the apex at 2 months (relative uptake, LAD/normal = .76) to a larger and more severe defect 3 months after instrumentation (relative uptake = .50). The increasing size and severity of the HED defects parallels the changes in stenosis severity as this model progresses from chronically stunned to hibernating myocardium.16 Modified from Luisi et al.17 Reprinted with permission of the Society of Nuclear Medicine, Inc. Ant, anterior; Lat, lateral, Inf, inferior; Sep, septum.