Cardiovascular autonomic control in myotonic dystrophy type 1: a correlative study with clinical and genetic data.
The autonomic nervous system has been evaluated in myotonic dystrophy with contradictory results and its relationship with heart disturbances remains unclear. Twenty-three patients with myotonic dystrophy type 1 were investigated by a battery of six cardiovascular autonomic tests and power spectral analysis of heart rate variability. Although 15 patients (65%) revealed abnormal or borderline results in some tests, only one patient had a definite autonomic damage, as indicated by two or more abnormal tests. As a group, myotonic dystrophy type 1 patients showed a significant reduction of heart rate variability during deep breathing (P < 0.0001). The exclusive involvement of parasympathetic tests suggests that a mild vagal dysfunction occurs in some myotonic dystrophy type 1 patients. The results indicate that such autonomic abnormalities are not: (1) part of a peripheral neuropathy; (2) related to cytosine-thymine-guanine repeat size or breathing pattern. Power spectral analysis showed a reduction of supine low-frequency band, which is, but not exclusively, a marker of sympathetic activity. It was inversely correlated to disease duration (P < 0.04), suggesting a progression as the disease advances. A low-frequency power, recorded after standing, was significantly associated (P < 0.02) with presence of heart involvement. Our findings suggest that a mixed, especially parasympathetic, autonomic dysfunction may occur in myotonic dystrophy type 1, although it is not a major finding. It could play a role in the occurrence of cardiac abnormalities, or increase the risk of sudden cardiovascular events.
Di Leo
Rita
R
Department of Neurosciences, Psychiatry and Anaesthesiology, Clinica Neurologica 2, Policlinico Universitario, 98125 Messina, Italy. rita_dileo@tin.it
Rodolico
Carmelo
C
De Gregorio
Cesare
C
Recupero
Antonio
A
Coglitore
Sebastiano
S
Annesi
Grazia
G
Toscano
Antonio
A
Messina
Corrado
C
Vita
Giuseppe
G
D000293:Adolescent; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000235:genetics / Q000503:physiopathology; D001342:Autonomic Nervous System Diseases / Q000235:genetics* / Q000503:physiopathology*; D002320:Cardiovascular Physiological Phenomena; D002648:Child; D005260:Female; D006321:Heart / Q000294:innervation / Q000503:physiopathology*; D006334:Heart Function Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D009223:Myotonic Dystrophy / Q000235:genetics* / Q000503:physiopathology*; D018911:Trinucleotide Repeats / Q000235:genetics; D020421:Vagus Nerve Diseases / Q000235:genetics / Q000503:physiopathology