Low Blood Sugar & Heartbeat in People With Diabetes
Study found abnormal rhythms when blood sugar dipped at night in people with type 2 disease
"However, in animal studies, when blood sugar became severely low, more severe abnormal cardiac rhythms -- in other words, fatal heart rhythms -- were noted. So, based on existing animal and human data, we speculate that severe hypoglycemia-induced arrhythmias may contribute to sudden death in patients with insulin-treated diabetes," Fisher said.
He continued, "Nocturnal hypoglycemia is a major problem. People are less likely to wake up and treat their hypoglycemia at night. They're less likely to appreciate the normal warning symptoms of hypoglycemia because the entire sympathetic response is relatively blunted at night."
While the study found an association between low blood sugar levels and abnormal heart rhythms in people with type 2 diabetes, it did not prove a cause-and-effect relationship.
Another expert said the new findings highlight the dangers of hypoglycemia.
"This study suggests that the deeper the hypoglycemia, the more abnormal the heart rhythms. There seems to be some real scientific plausibility that recurrent episodes of hypoglycemia can cause abnormal disturbances of the heart. Each episode of hypoglycemia may have some element of risk," said Dr. John Anderson, the immediate past president of the American Diabetes Association.
"It may be that tight control of blood sugar might not be as important as safe control of blood sugar. Avoiding severe hypoglycemia should be a primary goal of therapy, especially for those who have a lot of risk for heart disease. That's why the American Diabetes Association said in 2012 that glycemic goals should be individualized. And, if you have to use insulin, avoiding those 3 a.m. hypoglycemias may be even more important," Anderson said.
In addition to changing target blood sugar goals, Anderson and Fisher both said that the use of a continuous glucose monitor with alarms could also help people avoid low blood sugar levels in the middle of the night. "[Continuous glucose monitoring] isn't thought of as much for the type 2 population. But, there are a lot of people with type 2 diabetes on insulin who have cardiovascular disease. This might be a prudent use of [continuous glucose monitoring]," Anderson said.
Fisher agreed, noting, "Technology -- like [continuous glucose monitors] and insulin pumps -- may be able to decrease the number of hypoglycemic episodes while still allowing patients to maintain tight glycemic control."