title: Cardiac autonomic control in patients with myasthenia gravis and thymoma.
abstract: OBJECTIVE
  To evaluate cardiac autonomic control in patients with myasthenia gravis (MG) and thymoma.
  
  
  METHODS
  The study was performed on 21 patients with MG and thymoma and the same number of matched healthy volunteers. Standard cardiovascular reflex tests according to Ewing and baroreflex sensitivity (BRS) at rest was applied. Spectral analysis of heart rate variability (HRV) at rest was assessed using a 20-minute ECG recording (normalized low- and high-frequency bands-LFnu-RRI, HFnu-RRI and LF/HF-RRI) Time-domain analysis of HRV was derived from 24-hour ECG monitoring.
  
  
  RESULTS
  Overall autonomic score according to Ewing was significantly increased in patients with MG and thymoma (p<0.05), mostly due to parasympathetic dysfunction. Time-domain parameters representing the overall and long-term sympathetic activity of HRV did not differ significantly between the two groups (p>0.05), but there was a significant decrease in measures of the short-term vagal variations in HRV (p<0.01). HFnu-RRI was lower, while LFnu-RRI and LF/HF-RRI were higher in patients with MG and thymoma in comparison to healthy controls but these differences were not of statistical significance (p>0.05). BRS at rest was highly significantly reduced in patients group (p<0.01).
  
  
  CONCLUSIONS
  Our results showed mainly parasympathetic cardiac impairment in patients with myasthenia gravis and thymoma. Since autonomic dysfunction may lead to cardiac conduction abnormalities and sudden death, the investigation of autonomic nervous system function in these patients may be significant in everyday clinical practice.
authors.affiliation: Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotica Street 6, 11 000 Belgrade, Serbia. stojanperic@gmail.com
authors.forename: S
authors.initials: S
authors.lastname: Peric
authors.forename: V
authors.initials: V
authors.lastname: Rakocevic-Stojanovic
authors.forename: T
authors.initials: T
authors.lastname: Nisic
authors.forename: S
authors.initials: S
authors.lastname: Pavlovic
authors.forename: I
authors.initials: I
authors.lastname: Basta
authors.forename: S
authors.initials: S
authors.lastname: Popovic
authors.forename: S
authors.initials: S
authors.lastname: Damjanovic
authors.forename: D
authors.initials: D
authors.lastname: Lavrnic
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000209:etiology; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis* / Q000209:etiology; D017704:Baroreflex / Q000502:physiology; D005260:Female; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000150:complications / Q000175:diagnosis*; D013945:Thymoma / Q000150:complications / Q000175:diagnosis*; D013953:Thymus Neoplasms / Q000150:complications / Q000175:diagnosis*; D020421:Vagus Nerve Diseases / Q000175:diagnosis* / Q000209:etiology