Endocrine Abstracts

Type 1 diabetes mellitus (DM1) accounts for 5 to 10% of DM cases, and can occur both in childhood and adults. Studies show an association between severe hypoglycemia and increased vulnerability to cardiac arrhythmias due to conduction disorders, interval ST-segment changes, and even sudden death. The aim of this study is to evaluate the occurrence of cardiac arrhythmias during episodes of hypoglycemia. A prospective study with DM1 patients under insulin therapy for at least 5 years, aged 18–60 years, of both sexes. Before study initiation, all patients underwent a two-dimensional echocardiogram and laboratory tests, and those who did not present structural heart disease or any hormonal alterations that could cause arrhythmias, were included. The study was approved by the Research Ethics Committee of the Institution and after signed the Informed Consent Forms, the intermittent interstitial glucose reading device (IPro2 - Medtronic/USA) was implanted and simultaneous electrocardiographic recording was performed by the Holter system (Cardios Systems/Brazil). The patients were monitored for hypoglycemia (defined as interstitial glucose value <70 mg/dl according to the International Diabetes Federation without any induction for this occurrence and arrhythmia detection for 24 hours. Twenty-two patients were studied. From these eight patients (36.3%) did not have hypoglycemia: two patients (25%) also had no arrhythmia, while six patients (75%) had arrhythmias interpreted as non-significant. Hypoglycemic events were detected in the other 14 patients (63.7%), corresponding in this scenario from 4% (55 minutes) to 68% (16 hours) of total monitoring time. In this group, seven patients (50%) presented no arrhythmia, while the other seven patients (50%) had some non-significant arrhythmia that is common in non-diabetic subjects, being more prevalent as ventricular and supraventricular extrasystoles, isolated/paired with low frequency and sinus tachycardia. In the evaluated group, we find no relation between episodes of hypoglycemia and clinically relevant cardiac arrhythmia.