Hypoglycemia is associated with acute changes in the QTc interval and reduced heart rate in type 2 diabetic patients with cardiovascular disease in a real world setting

Hypoglycaemia can lead to severe cardiac arrhythmias, which are harmful for patients with type 2 diabetes and cardiovascular disease. Little is known about specific proarrhythmic ECG changes, which can occur during hypoglycemic events in a real world setting.

Materials and methods:

We analysed 5-day continuous ECG and blood glucose levels of 54 patients with type-2-diabetes – 34 patients with hypoglycaemic episodes (HE) and 20 patients without. We examined the ECG of the Hypo-Group 2h and 1h before, during, 1h and 2h after HE. As a control we used an episode of stable blood glucose level in the Hypo-Group as well as in the Non-Hypo-Group.

Results:

In comparison to the episode of stable blood glucose level of the Hypo-Group (427,5 ms ± 16,7 ms) and the Non-Hypo-Group (428,4 ms ± 23,6 ms, p < 0.05), the QTc-time increased (438,6 ms 23,3 ms, p = 0,001) during the HE. We observed a lower maximal heart rate during HE (81,3 ± 14 bpm) compared to 2h before (2h pre: 86,8 ± 16 bpm, p < 0.05), 2h after the HE (2h post: 86,9 ± 15,8 bpm, p < 0.05) and during stable blood glucose levels (83,1 ± 14,4 bpm). However, we found no direct timely association between HE and ventricular arrhythmias.

Conclusion:

Our data show that acute HE are associated with a reduction in heart rate and a prolonged QTc-time, which might predispose frail patients to severe arrhythmic events. Our data are in line with experimental data and should encourage the practitioner to focus on stable glucose control.