Abnormal diastolic blood pressure and heart rate reactions to tilting in diabetes mellitus.

The orthostatic reaction to tilting was studied in 46 diabetics without symptoms of autonomic neuropathy and in 31 age-matched healthy control subjects. After tilting, the diastolic blood pressure rose in the control subject but was unchanged or tended to fall in the diabetics, except in those of short duration without retinopathy. After tilting, the control subjects showed an immediate increase in heart rate with the highest value at 8.4 +/- 1.0 s (mean +/- SEM), followed by a transient decrease with lowest value at 21.2 +/- 0.9 s. The acceleration and brake index measured the changes in heart rate. The brake index was lower in diabetics of short duration with retinopathy (6.9 +/- 1.6) than in those without (14.4 +/- 2.3, P < 0.01) as well as matched control subjects (18.7 +/- 2.5, P 0.01). In the diabetics of long duration no differences were shown between those with or without retinopathy but the accleration (10.3 +/- 1.6 vs 19.9 /!- 2.3, P < 0.05) and the brake index (5.3 +/- 1.4 vs 19.9 +/- 2.3, P < 0.01) were lower in those with vagal neuropathy.