Evidence of cardiovascular autonomic impairment in mitochondrial disorders.
OBJECTIVE
To investigate autonomic nervous system (ANS) function in mitochondrial disorders (MD).


BACKGROUND
MD are characterized by a wide range of clinical features, including heart abnormalities and peripheral and central nervous systems involvement. Rarely autonomic symptoms have been reported.


METHODS
22 patients with MD underwent a battery of cardiovascular reflex tests including five tests of parasympathetic function and four tests of sympathetic function. Power spectral analyses (PSA) of heart rate variability in the supine and upright positions were also evaluated. Plasma levels of adrenaline, noradrenaline and dopamine were determined in the standing and lying positions.


RESULTS
Only 4/22 patients referred symptoms related to ANS dysfunction. 46% of patients had a definite autonomic damage (i. e. an autonomic score >/= 4). 36% showed moderate alterations with an autonomic score in the range 2-3 and 18 % had a normal autonomic function. MD patients had a significantly (p <0.03) lower increase of adrenaline level after standing.


CONCLUSIONS
Our data indicate an autonomic dysfunction in more than 80% of MD patients, even in the absence of a clinically manifested autonomic involvement. Cardiovascular autonomic investigation might be systematically employed in the characterization of MD.
Di Leo
Rita
R
Department of Neurosciences Psychiatry and Anaesthesiology, University of Messina, Via Consolare Valeria 98125, Messina, Italy.
Musumeci
Olimpia
O
de Gregorio
Cesare
C
Recupero
Antonio
A
Grimaldi
Patrizia
P
Messina
Corrado
C
Coglitore
Sebastiano
S
Vita
Giuseppe
G
Toscano
Antonio
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001342:Autonomic Nervous System Diseases / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*; D004298:Dopamine / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D028361:Mitochondrial Diseases / Q000150:complications*; D009638:Norepinephrine / Q000097:blood; D013057:Spectrum Analysis / Q000379:methods; D018709:Statistics, Nonparametric; D016683:Supine Position / Q000502:physiology
D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine