Assessment of heart rate variability and cardiac autonomic profile in patients with myasthenia gravis

In this study we aimed to assess cardiac autonomic profile of patients with MG by using noninvasive cardiovascular reflex tests and to detect that whether it associates with thymoma and AChR Ab positivity or not if cardiac autonomic involvement is detected. 30 patients (15 male, 15 female) with MG who are being followed by Akdeniz University Faculty of Medicine Neuromuscular Disorders outpatient clinic were included in the study. 30 healty people whose ages and genders are concordant were defined as control group. People who have chronic systemic diseases such as diabetes mellitus, previously diagnosed with cardiac disease, smoke or have a history of drug use that affects autonomic nervous system were excluded. Tasc Force Monitor tool (cardiac hemodynamic and autonomic parameters) and Ewing Battery Test were used to assess autonomic dysfunction. Besides, Modified Ewing Battery Test was obtained by adding two variables to the Ewing Battery Test. Hemodynamic parameters were compared between the two group and it was seen that mean values of SBP and DBP were higher in the patient grup than control group. LF and LF/HF ratios were higher but HF and BRS values were lower in the results of spectral analysis of heart rate variability. These results were interpreted as follows: sympathovagal balance is impaired in the direction of increased sympathetic tone and parasympathetic failure is more prominent in MG patients. There is no significant relationship with the presence of thymoma and AChR Ab positivity in subgroup analyzes of results. None of the patients with MG had abnormal results (autonomic involvement) of Original and Modified Ewing Battery Score. Parasympathetic disorders were detected in only 3 patients' Modified Ewing battery score results. Determining cardiac autonomic function by using noninvasive methods among patinets with MG has a high predictive value. Identifying autonomic dysfunction at an early stage and early treatment of cardiovascular diseases can reduce morbidity and mortality. In this way, autonomic dysfunction induced arrhythmias and sudden deaths can be prevented