A correlation may exist between asymptomatic episodes of ventricular arrhythmias and silent hypoglycemic episodes….
Markolf Hanefeld, MD, PhD, of Technical University Dresden in Germany, and colleagues believe this may provide an explanation for the risk of sudden death during instances of hypoglycemia in patients with coexisting diabetes and cardiovascular disease.
In the study, patients were only able to identify a few minor symptomatic hypoglycemic episodes, but with continuous monitoring there was a multitude of serious ventricular arrhythmias recorded, reported the research team at the annual European Association for the Study of Diabetes meeting.
Hanefeld stated in his verbal presentation that what motivated him and his research team to conduct the study was data from other studies showing severe hypoglycemic events being associated with cardiovascular deaths. This spurred the team to recruit 29 men and 1 woman with diagnosed diabetes and documented cardiovascular disease.
The participants were monitored continuously with a Medtronic MiniMedGold device to track interstitial subcutaneous glucose levels for 2-5 days. They also were monitored continuously with an Amedec ECGPro for 5 days. By the end of the study, the research team was able to demonstrate that episodes of mild hypoglycemia, even those that were asymptomatic, were correlated with episodes of ventricular arrhythmia.
The patient population was typically 68 years old with an average A1c of 7.3%, and were maintained on an insulin or oral antidiabetes regimen. Of the 30 participants, 19 participants did not have a severe hypoglycemic event, which is classified as a blood glucose level less than 3.1 mmol/L (56 mg/dL). A hypoglycemic episode was classified as anytime a blood glucose level was less than 70 mg/dL (3.9 mmol/L). The mean number per participant of episodes of hypoglycemia was 2.60 and the number per patient for episodes of severe hypoglycemic events was 1. The majority of severe hypoglycemic events were seen at night with 24 total, while daytime events was 11. When the researchers analyzed for arrhythmias, they found that 17 participants suffered couplets, 10 participants suffered triplets, and 5 patients suffered ventricular tachycardia.
The research team was able to reveal that some of the cases had an overlap of both hypoglycemic and arrhythmic events. However, Hanefeld mentioned that, "In this heterogeneous group of patients with a polypharmacy of cardiovascular drugs, we could not find a direct relationship between parameters of glycemic variability, quality of diabetes control, and risk of severe arrhythmias." However, Hanefeld and colleagues did observe that there was a higher frequency of ventricular arrhythmic episodes when there was a longer period of hypoglycemia.
"Large scale prospective trials with continuous glucose monitoring and electrocardiography recording are needed to develop a risk score to single out patients at high risk for fatal arrhythmias," Hanefeld said.
EASD 2013; Abstract 231.