Several clinical trials have noted an association between hypoglycemia and major cardiovascular events; however, a direct link between antecedent hypoglycemia and worse cardiac outcomes has not been established. We hypothesized that antecedent recurrent hypoglycemia predisposes the heart to increased damage following a subsequent myocardial infarction. To test this hypothesis, adult Sprague Dawley rats were subjected to 3 days of recurrent insulin-induced hypoglycemia (25-30 mg/dl, 90 minutes each day; n = 6) or saline (control, n = 6) . On the following day, all rats underwent a myocardial infarction (MI) induced by occlusion of the left anterior descending artery for 30 minutes followed by reperfusion for 60 minutes. Electrocardiograms indicated ST elevation during the MI, which returned to normal sinus rhythm upon reperfusion. Hearts were removed immediately and analyzed for damage. MI induced ventricular damage from rats that underwent antecedent recurrent hypoglycemia (39 ± 5%) was significantly higher than control rats (16 ± 4%; p<0.001, Figure) . Additionally, plasma norepinephrine levels were elevated 14-fold in rats that underwent recurrent hypoglycemia. These studies indicate that antecedent hypoglycemia directly contributes to worse outcomes following an MI and that increased norepinephrine is associated with this damage.
C.G.Christensen: None. S.Fisher: None. C.M.Reno: None.
University of Utah’s Driving Out Diabetes, a Larry H. Miller Family Wellness InitiativeNational Institutes of Health (P30 DK020579) Juvenile Diabetes Research Foundation (1-FAC-2020-984-A-N)
