Correlation of indicators of glycemic variability and cardiac arrhythmias in patients with type 1 diabetes mellitus
Authors:   Pavlov First Saint Petersburg State Medical University, Chernaya M.E. ,   Saint Petersburg, Russian Federation, Korchagina Zh.V. ,   Pavlov First Saint Petersburg State Medical University; Saint Petersburg, Russian Federation, Khalimov Yu.Sh. ,   Pavlov First Saint Petersburg State Medical University; Saint Petersburg, Russian Federation, Butomo M.I. ,   Pavlov First Saint Petersburg State Medical University; Saint Petersburg, Russian Federation, Shikhaliev D.R. ,   Pavlov First Saint Petersburg State Medical University; Saint Petersburg, Russian Federation, Nersesyan A.A. ,   Pavlov First Saint Petersburg State Medical University; Saint Petersburg, Russian Federation, Lisker A.V. ,   Pavlov First Saint Petersburg State Medical University; Saint Petersburg, Russian Federation, Volkova A.R. ,   Pavlov First Saint Petersburg State Medical University; Saint Petersburg, Russian Federation
Published: December 2023

Objective: To study indicators of glycemic variability (GV) and their relationship with cardiac arrhythmias in patients with type 1 diabetes mellitus according to glucocardiomonitoring data. Design: Cross-sectional study. Materials and methods. The study included 72 patients with type 1 diabetes without previously diagnosed cardiovascular pathology. Of these, 34 patients received insulin pump therapy, 38 received multiple insulin injections. The average age of patients was 39.7 ± 15.9 years, the average duration of type 1 diabetes was 15.4 ± 10.8 years. The level of glycated hemoglobin (HbA1c) was determined in patients, and according to continuous glucose monitoring (CGM), GV indices were calculated: SD (standard deviation), CONGA (continuous overall net glycemic action), LI (lability index), MAGE (mean amplitude of glycemic excursions), MAG (mean absolute glucose). Simultaneously with CGM, Holter monitoring of the electrocardiogram was carried out: heart rate (HR), the presence and time of occurrence of arrhythmias, variability of the corrected QT interval (QTc), and the presence of ischemic changes were assessed. A correlation analysis of the relationships between GV levels and heart rhythm disorders was carried out. Results. Regardless of the type of insulin therapy, GV indicators in patients with type 1 diabetes were higher than the reference values for healthy individuals. Only 19 (26%) patients reached the target HbA1c level. In 62 (86%) people, various heart rhythm disturbances were registered, in 30 (42%) of patients there was a decrease in the circadian index (CI) of heart rate, and in 14 (19%) there was a prolongation of the QTc interval. The results of the correlation analysis showed that with an increase in GV, the HR CI decreased and the frequency of supraventricular and ventricular extrasystoles increased. Conclusion. The detected changes in heart rhythm against the background of increased GV in patients with type 1 diabetes indicate a high risk of developing a cardiovascular process. Strict glycemic control and normalization of GV can better reduce the risk of cardiac arrhythmia and the development of DCAN in patients with type 1 diabetes. Keywords: type 1 diabetes mellitus, glycemic variability, cardiovascular disease, diabetic cardiovascular autonomic neuropathy