[Comparative value of 24-hour ECG monitoring and standardized maneuvers in the detection and exploration of cardiac autonomic neuropathy in diabetics].

24-hour continuous electrocardiographic ECG monitoring and standardized tests were performed to detect cardiac autonomic neuropathy in diabetic patients. Thirty-eight patients, with a mean duration of diabetes of 10 years, twenty-five IDDM and thirteen NIDDM, and thirty-two controls, with no illness or treatment which could alter the heart rate (HR), were studied. Five standardized tests were performed. Three tests investigated parasympathetic function: variations of HR during Valsalva manoeuvre, deep breathing and standing. The other two tests investigated sympathetic function: detection of orthostatic hypotension and blood pressure response to sustained handgrip. Parasympathetic HR control was impaired in twenty-nine patients, together with impaired sympathetic cardiovascular control in seven. According to the 6 indices studied, 24-hour ECG monitoring detected abnormalities in only eight patients. Mean minimum 24-hour HR and mean sleeping HR were elevated in the group of patients whose five standardized tests were normal and in the group of patients with impairment of both parasympathetic and sympathetic cardiovascular control, but not in the group of patients with only impaired parasympathetic HR control. This study suggests that 24-hour ECG monitoring is a less sensitive test of cardiac autonomic neuropathy than standardized tests. Moreover, it shows HR abnormalities that are not specific to cardiac autonomic neuropathy.