Impairment of cardiac autonomic control in patients with amyotrophic lateral sclerosis

The aim of this study was to investigate autonomic cardiac control in patients with amyotrophic lateral sclerosis (ALS). Fifty-five patients with sporadic ALS (28 female and 27 male; average age 56.00 +/- 10.34 years) were compared to 30 healthy controls (17 female and 13 male; average age 42.87 +/- 11.91 years). Patients with previous history of cardiac disease, diabetes mellitus, and impaired respiratory function were excluded from the study. Cardiovascular autonomic tests according to Ewing, power spectrum analysis of RR variability (low- and high-frequency bands - LF and HF, LF/HF index), real-time beat-to-beat ECG signal monitoring with heart rate variability analysis and baroreflex function analysis were carried out in all patients. Time-domain parameters of heart rate variability (mean RR interval, SDNN, SDANN, SDNN index, rMSSD and pNN50%) were obtained from 24-h ECG monitoring. ALS patients had a significantly higher score of sympathetic (p < 0.01) and parasympathetic (p < 0.001) dysfunction, as well as of the overall score of autonomic dysfunction (p < 0.001). LF/HF index was significantly increased; baroreflex sensitivity and time-domain parameters of heart rate variability were highly significantly decreased in ALS patients (p < 0.001). Our results demonstrated impaired cardiac autonomic control in ALS with marked parasympathetic dysfunction and sympathetic predominance.