title: Hypoglycaemia and cardiac arrhythmias in patients with type 2 diabetes mellitus.
abstract: Improved blood glucose control by insulin treatment in patients with Type 2 (non-insulin dependent) diabetes mellitus increases the risk for hypoglycaemic episodes. Our objective was to investigate if hypoglycaemia causes electrocardiographic changes and cardiac arrhythmias in patients with Type 2 diabetes. Six insulin-treated patients with Type 2 diabetes and no known cardiac disease took part in the study. Hypoglycaemia was induced by insulin infusion aiming at a plasma glucose less than or equal to 2.0 mmol l-1 or hypoglycaemic symptoms. All patients experienced hypoglycaemic symptoms. The median lowest arterial plasma glucose was 2.0 mmol l-1. Arterial plasma adrenaline concentration increased from 0.4 +/- 0.1 (mean +/- SE) to 6.9 +/- 0.3 nmol l-1 (p less than 0.001) while serum potassium was lowered from 4.1 +/- 0.3 mmol l-1 to 3.5 +/- 0.2 mmol l-1 (p less than 0.001). The heart rate increased significantly during hypoglycaemia except in one patient who developed hypoglycaemic symptoms and a severe bradyarrhythmia at a plasma glucose of 4.4 mmol l-1. One patient developed frequent ventricular ectopic beats during hypoglycaemia while four patients showed no arrhythmia. ST-depression in ECG leads V2 and V6 was observed during hypoglycaemia in five patients (p less than 0.05) and four patients developed flattening of the T-wave. In conclusion, the study supports the hypothesis that hypoglycaemia in patients with Type 2 diabetes may be hazardous by causing cardiac arrhythmias.
authors.affiliation: Department of Internal Medicine, Faculty of Health Sciences, Linköping University, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Lindström
authors.forename: L
authors.initials: L
authors.lastname: Jorfeldt
authors.forename: L
authors.initials: L
authors.lastname: Tegler
authors.forename: H J
authors.initials: HJ
authors.lastname: Arnqvist
mesh_terms: D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000503:physiopathology; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D002096:C-Peptide / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000503:physiopathology; D004562:Electrocardiography; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006801:Humans; D007003:Hypoglycemia / Q000139:chemically induced / Q000503:physiopathology*; D007328:Insulin / Q000009:adverse effects* / Q000627:therapeutic use; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D011188:Potassium / Q000097:blood
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D011188:Potassium; D009638:Norepinephrine; D004837:Epinephrine