Abstract 18363: Type 1 and Type 2 Cardiac Autonomic Neuropathy in Type 1 and Type 2 Diabetes Mellitus
Introduction: Cardiac autonomic neuropathy (CAN) is a complication of diabetes mellitus (DM) that is associated with increased mortality. The severity of CAN may be related to type and duration of DM.
Methods: 16 subjects with type 1 DM (age 32.9±10.1 years), 18 subjects with type 2 DM (55.4±8.0 years) and 30 controls (44.0±11.6 years) underwent exercise-based assessment of CAN. Two 16-minute submaximal bicycle tests were performed followed by 45 minutes of recovery. Continuous 12-lead electrocardiography was performed. On the 2nd test, atropine (0.04 mg/kg) was administered at peak exercise so that all of recovery occurred under parasympathetic blockade. Plasma epinephrine and norepinephrine levels were measured at rest, during exercise, and during recovery. For each subject and at each time point in recovery, parasympathetic effect on the RR interval was defined as the difference of the RR interval at baseline without atropine and the RR interval after parasympathetic blockade with atropine.
Results: There were no differences in resting or peak exercise heart rates in the 3 groups. Parasympathetic effect on RR intervals during recovery (p<0.03) and heart rate recovery (p=0.02) were blunted in type 2 DM. Type 1 DM had higher baseline epinephrine and norepinephrine levels (p<0.03), and exhibited persistent sympathoexcitation during recovery.
Conclusions: Both type 1 and type 2 DM exhibit subtle abnormalities in autonomic function, but differentially affect the parasympathetic and sympathetic limbs of the autonomic nervous system. This is the first report of variable pathophysiology for CAN in type 1 versus type 2 DM.
Author Disclosures: D.J. Pelchovitz: None. J. Ng: None. H. Subacius: None. A.B. Chicos: None. D.W. Bergner: None. S. Banthia: None. M. Molitch: None. J.J. Goldberger: None.
- © 2015 by American Heart Association, Inc.