Hypoglycemia and cardiac arrhythmias in diabetes mellitus

The article provides an assessment of cardiovascular risks associated with episodes of hypoglycemia in patients with diabetes mellitus. The analysis has been performed for the experimental and clinical data on cardiac arrhythmias during induced hypoglycemia in animal models and in patients with diabetes. The pathogenetic mechanisms of the development of life‑threatening heart rhythm disorders during hypoglycemic states (in particular, changes in autonomic nervous system activation and in the serum level of potassium) have been considered. The nature of electrocardiographic changes preceding the development of arrhythmias during hypoglycemia is described and factors affecting QT interval duration during hypoglycemia are given. The authors highlight the results of clinical studies of spontaneous hypoglycemia in terms of the arrhythmias’ specific features in daytime and nocturnal hypoglycemia, and different mechanisms of the cardiac arrhythmias’ development at different periods of the day. Clinical data have been presented as regards the drug‑induced hypoglycemia during administration beta‑adrenergic receptor blockers, angiotensin‑converting enzyme inhibitors, fluoroquinolones, as well as mechanisms of dysglycemic effects of these drugs. It has been noted that β‑blockers can mask symptoms of catecholamine‑mediated hypoglycemia. It has been established that among hypoglycemic agents, insulin secretion stimulators (sulfonylureas, meglinides) and insulin have the highest risk of serious hypoglycemia. However, the use of basal and prandial insulin analogues was associated with a lower frequency of hypoglycemia compared to human insulin. It was emphasized that hypoglycemia should be avoided in clinical practice to improve prognosis and prevent arrhythmias. For this, it is necessary to individualize target glycemic values with their mitigation in high‑risk patients, to use the safest insulin and non‑insulin hypoglycemic agents, and to implement new technologies (pumps, continuous glucose monitoring) more widely. It is extremely important to take into account comorbidity and the effects on hypoglycemia risk of drugs used for the treatment of concomitant diseases.