Heart rate variability analysis of electrocardiography in pediatric immune-mediated autonomic neuropathy

: Immune-mediated autonomic neuropathies are difficult to diagnose in childhood because of the extreme rarity, nonspecific symptoms, and infrequent detection of autoantibodies specific to the disorders. There is a need for objective testing methods that are easily applicable to pediatric patients. Case 1 was a 13-year-old boy who showed autonomic symptoms of fatigue, tachycardia, and hypertension with sensorimotor impairments, including diminished tendon reflexes, delayed nerve conduction, and enhanced peripheral nerves on MRI. Case 2 was a 9-year-old boy who exhibited autonomic signs of postural orthostatic tachycardia with no abnormalities in a nerve conduction test and MRI but decreased heart rate variability (HRV) on conventional electrocardiography (ECG). Case 3 was a 14-year-old girl with autonomic symptoms of hypohidrosis, constipation, and coughing episodes, with alteration of various HRV metrics on 24-hour Holter ECG. Although serum autoantibodies to ganglionic acetylcholine receptor were not detected in any patients, intravenous immunoglobulin therapy was effective in all cases, suggesting immune-mediated mechanisms. : In the latter two patients, the diagnosis of immune-mediated autonomic neuropathies was underscored by HRV on ECG, especially 24-hour Holter ECG. Further studies are required to establish its clinical significance.