Association of Hypoglycemia and Cardiac Ischemia

Abstract

OBJECTIVE -In some studies intensive diabetes treatment in patients with type 2 diabetes may be associated with increased cardiovascular events. It is not clear whether these events are related to hypoglycemic episodes. To determine whether episodes of hypoglycemia were more likely to be associated with cardiac ischemia than normoglycemia or hyperglycemia, we carried out a study in 21 patients with coronary artery disease (CAD) and type 2 diabetes treated with insulin who had good glycemic control.RESEARCH DESIGN AND METHODS -We carried out 72-h continuous glucose monitoring along with simultaneous cardiac Holter monitoring for ischemia. Patients also recorded symptoms of cardiac ischemia (chest pain) and symptoms of hypoglycemia.RESULTS -Satisfactory continuous glucose monitoring system recordings were obtained in 19 patients. We recorded 54 episodes of hypoglycemia (blood glucose Ͻ70 mg/dl; 26 of these were symptomatic) and 59 episodes of hyperglycemia (blood glucose Ͼ200 mg/dl; none symptomatic). Of the 54 episodes of hypoglycemia, 10 were associated with symptoms of chest pain, during 4 of which electrocardiographic abnormalities were documented. In contrast, only 1 episode of chest pain occurred during 59 episodes of hyperglycemia. No chest pain or electrocardiographic abnormalities occurred when the blood glucose was within the normal range. The difference between the frequency of ischemia during hypoglycemia and the frequency during both hyperglycemia and normoglycemia was statistically significant (P Ͻ 0.01). There were 50 episodes during which the blood glucose changed by Ͼ100 mg over a 60-min period, and ischemic symptoms occurred during 9 of these episodes (P Ͻ 0.01 compared with stable normoglycemia or hyperglycemia).CONCLUSIONS -Hypoglycemia is more likely to be associated with cardiac ischemia and symptoms than normoglycemia and hyperglycemia, and it is particularly common in patients who experience considerable swings in blood glucose. These data may be important in the institution of insulin treatment and attempting near-normal glycemia in patients with known CAD. Further research is needed to determine strategies to prevent ischemia associated with hypoglycemia. Diabetes Care 26:1485-1489, 2003D iabetes is associated with an increased risk of development of coronary artery disease (CAD). Patients with CAD and diabetes have higher mortality and morbidity than patients without diabetes. Data from studies such as the U.K. Prospective Diabetes Study suggest that very good glycemic control is associated with fewer cardiovascular events (1). However, tight glycemic control may increase the risk of hypoglycemia. Increased cardiovascular events were noted in the Veterans Affairs Cooperative Study on Glycemic Control and Complications (VA CSDM), after the institution of tight glycemic control (2). It is possible that acute hypoglycemia may trigger ischemia and cardiovascular events. Hypoglycemia and rapid changes in blood glucose have been shown to increase counterregulatory hormones such as epinephrine ...

Transcriptional Co-activator p300 Maintains Basal Hepatic Gluconeogenesis

“…It is the sole energy source in some mammalian tissues and cells such as neurons, erythrocytes, and the renal medulla. Lower blood glucose (hypoglycemia) can damage these tissues and cells, even causes death (1,2). At the other extreme, hyperglycemia can cause serious adverse effects, which are clearly demonstrated in patients with diabetes (3,4).…”

Diabetes in older people: position statement of The Hong Kong Geriatrics Society and the Hong Kong Society of Endocrinology, Metabolism and Reproduction

“…40 Diabetic patients with concomitant coronary artery disease who experience hypoglycaemia are particularly prone to ischaemic heart attack. 41 These have clinical implications-in patients with multiple comorbidities, intensive glucose treatment may not be beneficial, but might make patients prone to treatment-related hypoglycaemia which, in turn, may exacerbate the cardiovascular event, especially in those at risk for cardiovascular disease.…”

Coronary Artery Disease and Diabetes Mellitus

“…34,35 Plausible mechanisms by which hypoglycemia might cause cardiovascular events or lead to death from cardiovascular disease include sympathoadrenal activation, abnormal cardiac repolarization, increased thrombogenesis, inflammation, and vasoconstriction leading to cardiac ischemia or fatal arrhythmia during recognized or unrecognized episodes of hypoglycemia. 36,37 Although the relationship in hospitalized patients with acute MI between hypoglycemia and cardiovascular outcomes is complex, 38 there was a clear J-shaped relationship between glucose values and adverse outcomes, including increased mortality. 39,40 In this context, hypoglycemia has been shown to lower myocardial blood flow reserve 41 and increase experimental infarct size.…”