title: QTc and autonomic neuropathy in diabetes: effects of acute hyperglycaemia and n-3 PUFA.
abstract: OBJECTIVE
  Autonomic function is also regulated by glycaemia and exerts a crucial role in the control of blood pressure and cardiac function. The disruption of this physiological mechanism impacts deeply on cardiovascular mortality in diabetes. We investigated the influence of autonomic dysfunction on QTc interval and on sympatho-vagal balance (LF/HF), in response to acute hyperglycaemia and to membrane electrical stabilization (n-3 PUFA).
  
  
  RESULTS
  Twenty-four type 2 diabetic patients, without (N-: n=13) or with (N+: n=11) autonomic neuropathy and 13 healthy subjects (C) underwent BP and ECG monitoring during a 24-h period and during a 2-h hyperglycaemic clamp. Delta QTc during the night was blunted in diabetics (0.5+/-2.5 vs. C: 2.9+/-2.5%, p=0.001), and Delta LF/HF was decreased in N+ (-2.8+/-38.2 vs. C=34.8+/-28.1%, p=0.02). During hyperglycaemia, QTc increased in C; LF/HF significantly increased in C and N-. A 6-month treatment with n-3 PUFA partially restored Delta LF/HF and Delta QTc (2.1+/-1.40, p=0.04 vs. basal) only in N-.
  
  
  CONCLUSIONS
  Hyperglycaemia increases QTc interval and sympathetic activity; electrical membrane stabilization improves autonomic function only in the absence of overt autonomic neuropathy. Strategies to prevent the disruption of autonomic function with newer approaches, other than just glucose control, should be implemented.
authors.affiliation: Diabetes Centre, Department of Internal Medicine, University Tor Vergata, Viale Duilio Cambellotti 11, I-00133 Rome, Italy.
authors.forename: Vanina
authors.initials: V
authors.lastname: Santini
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Ciampittiello
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Gigli
authors.forename: Daniela
authors.initials: D
authors.lastname: Bracaglia
authors.forename: Alessandra
authors.initials: A
authors.lastname: Baroni
authors.forename: Elena
authors.initials: E
authors.lastname: Cicconetti
authors.forename: Cristian
authors.initials: C
authors.lastname: Verri
authors.forename: Sergio
authors.initials: S
authors.lastname: Gambardella
authors.forename: Simona
authors.initials: S
authors.lastname: Frontoni
mesh_terms: D001341:Autonomic Nervous System / Q000502:physiology*; D001342:Autonomic Nervous System Diseases / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D048909:Diabetes Complications; D003924:Diabetes Mellitus, Type 2; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D004562:Electrocardiography; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005260:Female; D015309:Glucose Clamp Technique; D006334:Heart Function Tests; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006943:Hyperglycemia / Q000150:complications*; D008297:Male; D008875:Middle Aged
chemical_list: D015525:Fatty Acids, Omega-3