The aim of this systematic review is to investigate the association between ALS and cardiovascular autonomic neuropathy (CAN).

Patients with amyotrophic lateral sclerosis (ALS) may have damage to the autonomic nerve fibers that innervate the heart and blood vessels, resulting in abnormalities in the cardiovascular system.

A total of 23 studies were included for data extraction after an initial search strategy was established for Ovid MEDLINE and was applied to CINAHL-EBSCOhost, Embase, and Cochrane Library. The included studies reported adult patients with a primary diagnosis of ALS and features of CAN who underwent assessment of heart rate variability (HRV), baroreflex sensitivity (BRS), cardiac arrhythmia and postganglionic adrenergic cardiac denervation, resting tachycardia, and orthostatic hypotension (OH).

The majority of the studies showed reduced HRV, which is the hallmark of CAN diagnosis. Resting tachycardia has been demonstrated in patients with ALS in several studies. Nine studies evaluated orthostatic blood pressure changes. Six of them showed no significant OH. OH was seen only in three studies; in one of them, it was seen in approximately 6% (8 /132) of patients with ALS who underwent neurological evaluation and autonomic testing. The number of IML in the upper thoracic cord was significantly lower in ALS patients compared to controls. Two studies showed abnormal (123I) metaiodobenzylguanidine (MIBG) uptake in ALS patients and one of them showed evidence of postganglionic sympathetic adrenergic cardiac denervation. An overall reduction in BRS in ALS patients has been shown in a few studies.

Our study demonstrated an association between ALS and CAN. Reduced HRV, resting tachycardia, abnormal baroreflex sensitivity, and evidence of postganglionic sympathetic adrenergic cardiac denervation have been demonstrated in patients with ALS in multiple studies.