| Summary: | This study assessed cardiac autonomic response to head-up tilt test (HUTT) in 23 myasthenia gravis (MG) and 23 relapsing-remitting multiple sclerosis (RRMS) patients compared to 30 healthy controls (HC). Task Force<sup>®</sup> Monitor was used to evaluate cardiac inotropy parameters, baroreflex sensitivity (BRS), heart rate (HRV), and blood pressure variability (BPV) during HUTT. MG patients were characterized by reduced BRS (<i>p</i> < 0.05), post-HUTT decrease in high-frequency component (<i>p</i> < 0.05) and increase in sympathovagal ratio of HRV (<i>p</i> < 0.05) when compared to controls indicating parasympathetic deficiency with a shift of sympathovagal balance toward sympathetic predominance. Compared to HC, MG patients also showed lower cardiac inotropy parameters, specifically, left ventricular work index (LVWI) during supine rest (<i>p</i> < 0.05) as well as LVWI and cardiac index values in response to orthostatic stress (<i>p</i> < 0.01 and <i>p</i> < 0.05, respectively). Compared to controls, RRMS patients were characterized by lower HRV delta power spectral density (<i>p</i> < 0.05) and delta low-frequency HRV (<i>p</i> < 0.05) in response to HUTT suggesting combined sympathetic and parasympathetic dysfunction. There were no differences in cardiac autonomic parameters between MG and MS patients (<i>p</i> > 0.05). Our study highlights the possibility of cardiac and autonomic dysfunction in patients with MG and RRMS which should be considered in the pharmacological and rehabilitation approach to managing these conditions.
|
|---|
