Brain natriuretic peptide and cardiac autonomic function in type 2 diabetic patients

The present study tested the hypothesis that increased plasma brain natriuretic peptide (BNP) levels are related to cardiac autonomic dysfunction in type 2 diabetic patients. A total of 32 consecutive Japanese patients with type 2 diabetes were assigned to either a high-BNP (≥18 pg/ml) group (n = 12; age 57 ± 13 years, mean ± S.D.) or a normal-BNP (<18 pg/ml) group (n = 20; 59 ± 10 years). No patient had any overt structural heart disease. Cardiac autonomic function was assessed by measurements of baroreflex sensitivity (BRS), heart rate variability (HRV) and cardiac 123I-metaiodobenzylguanidine (MIBG) scintigraphic findings. BRS was lower (p < 0.005) in the high-BNP group than in the normal-BNP group. However, the components of HRV, and the early and delayed myocardial uptake of 123I-MIBG and percentage washout rate of 123I-MIBG were not significantly different between the groups. The plasma level of BNP negatively correlated with BRS (r = 0.35, p = 0.049). These findings suggest that increased plasma BNP levels were related to cardiac reflex parasympathetic dysfunction in our Japanese type 2 diabetic patients.