The energetic state within hibernating myocardium is normal during dobutamine despite inhibition of ATP-dependent potassium channel opening with glibenclamide.

Within hibernating myocardium, it is uncertain whether a normal energetic state is present at baseline and whether maintaining that energy state during a catecholamine challenge is dependent on ATP-dependent potassium channel opening. In this study, 16 swine underwent a thoracotomy with placement of an external constrictor on the left anterior descending coronary artery (LAD) (hibernation model). Seven additional swine underwent a sham operation. At 10 wk, the myocardial energetic state in the LAD region was assessed by 31P-NMR spectroscopy, and the ratio of phosphocreatine to ATP (PCr/ATP) was determined at baseline, during glibenclamide treatment (0.5 mg/kg bolus with 50 μg/min iv), and during addition of dobutamine (40 μg·kg−1·min−1 iv). At baseline, transmural blood flow in the LAD and remote region was 0.75 ± 0.11 and 0.88 ± 0.09 ml·min−1·g−1, respectively (P < 0.01), in hibernating hearts and 0.83 ± 0.12 and 0.88 ± 0.15 ml·min−1·g−1, respectively (not significant), in sham-operated hearts. Under bas...