Effect of autonomic dysfunction on anginal perceptual threshold in diabetes mellitus

ABSTRACT

In diabetes anginal perceptual threshold may be delayed. To investigate the pathogenesis of delayed anginal perceptual threshold we examined 80 subjects classified into a control group [n = 24] not diabetics but with other risk factors and a diabetic group [n = 56]. Diabetic patients were subdivided according to prior autonomic function testing into a group with normal autonomic functions [n = 30] and a group with autonomic neuropathy [n = 26]. All subjects underwent treadmill exercise after assessment of their autonomic functions. Anginal perceptual threshold, defined as the time from onset of exertional >/= 1 mm ST-segment depression to onset of chest pain, was measured in all cases with exercise-induced angina. Silent myocardial ischemia was encountered in 14.3% of diabetic patients vs 0% in nondiabetic control subjects. This percentage was significantly higher in diabetics with than in diabetics without autonomic neuropathy [23.08% vs 6.67% respectively] [P < 0.01]. Exercise-induced angina was significantly higher in diabetics than in non diabetics [32% vs 16.67% respectively] [P < 0.01], with no -significant difference between diabetics with and without autonomic neuropathy. Anginal perceptual threshold was significantly prolonged in diabetics than in non-diabetics [114.4 +/- 6.3 sec vs 45 +/- 7.5 sec]