All swine underwent unipolar voltage (UPV) mapping (top panel), myocardial blood flow (MBF) measurements with microspheres (middle panel), and transthoracic echocardiography (bottom panel) before myocardial injection of either phVEGF₁₂₅ or saline. The UPV scores from the Noga map in the ameroid territory were reduced compared with those in the remote myocardium but in the viable range. MBF in cc/g/min was mildly reduced in the ameroid territory compared with that in the remote myocardium. The percent wall thickening in the ameroid territory was reduced compared with that in the remote myocardium. These findings of abnormally functioning but viable myocardium fulfill the criteria for hibernation.

Myocardial blood flow (MBF) is expressed as ratio of MBF in the ameroid territory to remote territory. The change (± SD) from immediately before intramyocardial injection of either phVEGF₁₆₅ or saline to 3 weeks after injection for both treatment and control experiments are expressed as percent. The blood flow ratio increased in the vascular endothelial growth factor (VEGF)-injected animals (orange bar) and decreased in the saline-injected animals (yellow bar). LAD = left anterior descending coronary artery; LCx = left circumflex artery.

Global and regional left ventricular (LV) function were measured using echocardiography immediately before and 3 weeks after intramyocardial injection with either phVEGF₁₂₅ (yellow bars) or saline (orange bars). Mean value for left ventricular ejection fraction (LVEF) increased slightly but with a large standard deviation (error bar) while mean value for LVEF fell in the saline-treated animals but also with a large standard deviation. Wall thickening (WT) in the ameroid territory increased slightly in the vascular endothelial growth factor (VEGF)-treated animals and fell in the saline-treated animals.

Values from quantitative immunohistology in the ameroid territory for the vascular endothelial growth factor (VEGF)-injected animals (yellow bars) and saline-injected animals (orange bars) are shown in the upper panel. The VEGF-injected experiments showed less fibrosis and greater capillary sprouting by lectin staining than the saline-injected control experiments. The bottom images show representative examples of tissue staining. Panel A shows a myocardial section stained for lectin from the injection territory from 1 VEGF experiment, and panel B shows 1 saline-injected animal. Brown staining of sprouting capillaries is seen in panel A and is absent in panel B. Panel C shows green fluorescence identifying integrin expression in capillary sprouts from the injection site of 1 VEGF-injected animal that showed in-vivo uptake of [¹²³I]Gluco-RGD. FITC = fluorescein.

Images shown on the left are unipolar voltage maps at the time of injection with the injection sites marked for 1 saline-injected animal and 1 vascular endothelial growth factor (VEGF)-injected animal. The 2 Noga maps on the right were acquired during the final study on the same 2 animals. The color bar in the right upper corner of each image corresponds to unipolar voltage values from 6 mV (orange) to 15 mV (pink). The saline-injected region shows a fall in unipolar voltage score, while the VEGF-injected region shows an increase in unipolar voltage score.

On the left are shown reconstructed short-axis (SA), vertical (VLA), and horizontal long-axis (HLA) single-photon computed tomography (SPECT) slices from the thallium scans (top rows) and I-123 scans (bottom rows) from 1 representative animal treated with vascular endothelial growth factor (VEGF) and 1 animal treated with saline. The VEGF-injected animal shows a mild anterolateral thallium defect and focal uptake of [¹²³I]Gluco-RGD into the anterolateral wall. The colocalization of the thallium defect and focal hotspot is better displayed on the polar maps. The saline-injected animal shows a mild-to-moderate anterolateral and apical defect without focal uptake of of [¹²³I]Gluco-RGD in the heart. RGD = arginine-glycine-aspartic acid.

Graph shows percent injected dose (ID) per gram of tissue for [¹²³I]Gluco-RGD plotted versus lectin staining as percent area for vascular endothelial growth factor-injected animals (yellow triangles) and saline injected (orange squares). Although the relationship is significant, there is not a perfect separation between the 2 groups. One saline-injected animal showed no focal hotspot in the myocardium but showed a higher level of background activity for I-123. One of the vascular endothelial growth factor-injected experiments had low uptake of [¹²³I]Gluco-RGD, which corresponded to lower levels of angiogenesis by lectin staining. RGD = arginine-glycine-aspartic acid.