Electrical changes during hypoglycaemia in patients with type 1 and type 2 diabetes and high cardiovascular risk

The relationship between glycaemia, arrhythmia and changes in electrocardiogram (ECG) has been addressed showing mixed results. The objective of this study was to evaluate the changes in ECG, evaluated by Holter monitoring, induced by clinical hypoglycaemia in patients with type 1 diabetes (T1DM) and type 2 diabetes (T2DM), aged 50 or older, with high cardiovascular risk. Five-lead Holter monitoring (BL-900 Braemar, Inc, Norav Medical NH301-2.4.5 software), and blinded interstitial continuous glucose monitoring (CGM) (Dexcom G4-Platinum, range 40–400 mg/dl) was performed with time synchronization. In the Holter registry, in patients with hypoglycemic episodes, mean QTc during hypoglycaemia was longer compared to mean QTc in total group (+4.6 ms, p = 0.037) and T1DM patients (+5.5 ms, p = 0.048) but not in T2DM patients (+3 ms, p = 0.459). During hypoglycaemia, non-clinical significant disturbances in heart rhythm were observed. In conclusion, we observed a prolongation in QTc during hypoglycemia, mainly in T1DM. However, our study does not show a relationship between episodes of hypoglycaemia and clinical arrhythmias, at least in T1DM and T2DM patients with high cardiovascular risk.