CORRELATION OF ALTERED Q-T INTERVAL AND SYMPATHETIC NERVOUS-SYSTEM DYSFUNCTION IN DIABETIC AUTONOMIC NEUROPATHY

We examined the relationship between the Q-T interval and autonomic dy sfunction in 74 diabetic patients and age-matched controls. The expect ed Q-T interval was standardized as a function of the R-R interval in 646 healthy controls, and the Delta Q-T defined as the difference from the expected value. Propranolol increased Delta Q-T, confirming this as a parameter of autonomic function. No relationship between Delta Q- T and duration of disease, glucose control, retinopathy or proteinuria was observed. However, significant correlations were found between th e Delta Q-T and delay of nerve conduction velocity, orthostatic hypote nsion, altered Valsalva ratio, abnormal Valsalva overshoot, cold press er response, decreased norepinephrine concentration and sympathetic fu nction score in diabetic patients.