Electrocardiographic Changes of Sinoatrial Dysfunction in Hypoglycemia: A Case Report

Acute and chronic hypoglycemia, induced by insulin or oral antidiabetic agents in a therapeutic context, is a cardiovascular risk factor that triggers endothelial dysfunction and atherogenesis via pro-inflammatory mechanisms. It may be equally or more relevant than hyperglycemia, with the added threat of inducing arrhythmogenic and ischemic sudden death. We present the case of a 61-year-old female patient with a medical history of diabetes mellitus, managed with long-acting insulin (30 units in the morning and 15 units at night), who developed fever, general malaise, and anorexia, followed by an episode of near syncope accompanied by profuse sweating. She was taken to the emergency department, where capillary blood glucose was found to be 2.4 mmol/L. A 12-lead ECG revealed sinus pauses, which resolved following administration of hypertonic dextrose. This case illustrates that hypoglycemia poses a real threat to the myocardium, not only due to its immediate proarrhythmic effects (linked to sudden death syndrome) but also due to its long-term proinflammatory and atherogenic effects, representing a major cardiovascular risk factor. Therefore, it is desirable and clinically pertinent to avoid hypoglycemic episodes of any intensity or duration in all diabetic patients—particularly those with underlying myocardial pathologies that increase the risk of sudden death: compromised systolic function, ventricular arrhythmias, atrial fibrillation, coronary artery disease, hypertrophic cardiomyopathy, arrhythmogenic genotype, and history of resuscitation.