Elevated plasma levels of cardiac troponin-I predict left ventricular systolic dysfunction in patients with myotonic dystrophy type 1: A multicentre cohort follow-up study.
OBJECTIVE
High sensitivity plasma cardiac troponin-I (cTnI) is emerging as a strong predictor of cardiac events in a variety of settings. We have explored its utility in patients with myotonic dystrophy type 1 (DM1).


METHODS
117 patients with DM1 were recruited from routine outpatient clinics across three health boards. A single measurement of cTnI was made using the ARCHITECT STAT Troponin I assay. Demographic, ECG, echocardiographic and other clinical data were obtained from electronic medical records. Follow up was for a mean of 23 months.


RESULTS
Fifty five females and 62 males (mean age 47.7 years) were included. Complete data were available for ECG in 107, echocardiography in 53. Muscle Impairment Rating Scale score was recorded for all patients. A highly significant excess (p = 0.0007) of DM1 patients presented with cTnI levels greater than the 99th centile of the range usually observed in the general population (9 patients; 7.6%). Three patients with elevated troponin were found to have left ventricular systolic dysfunction (LVSD), compared with four of those with normal range cTnI (33.3% versus 3.7%; p = 0.001). Sixty two patients had a cTnI level < 5ng/L, of whom only one had documented evidence of LVSD. Elevated cTnI was not predictive of severe conduction abnormalities on ECG, or presence of a cardiac device, nor did cTnI level correlate with muscle strength expressed by Muscle Impairment Rating Scale score.


CONCLUSIONS
Plasma cTnI is highly elevated in some ambulatory patients with DM1 and shows promise as a tool to aid cardiac risk stratification, possibly by detecting myocardial involvement. Further studies with larger patient numbers are warranted to assess its utility in this setting.
West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow, United Kingdom.|Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Mark J
http://orcid.org/0000-0001-9719-243X
MJ
Hamilton
Clinical Genetics Service, Western General Hospital, Edinburgh, United Kingdom.
Yvonne
Y
Robb
Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Sarah
S
Cumming
North of Scotland Clinical Genetics Service, Ashgrove House, Foresterhill Health Campus, Aberdeen, United Kingdom.
Helen
H
Gregory
West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
Alexis
A
Duncan
West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
Monika
M
Rahman
West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
Anne
A
McKeown
Human Genetics Unit, Ninewells Hospital, Dundee, United Kingdom.
Catherine
C
McWilliam
North of Scotland Clinical Genetics Service, Ashgrove House, Foresterhill Health Campus, Aberdeen, United Kingdom.
John
J
Dean
West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
Alison
A
Wilcox
Department of Neurology, Institute of Neurological Sciences, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
Maria E
ME
Farrugia
Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Anneli
A
Cooper
Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Josephine
J
McGhie
Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Berit
B
Adam
Department of Neurology, Institute of Neurological Sciences, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
Richard
R
Petty
West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
Cheryl
C
Longman
Inherited Cardiac Conditions Service, Queen Elizabeth University Hospital, Glasgow, United Kingdom.
Iain
I
Findlay
Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom.
Alan
A
Japp
Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
Darren G
DG
Monckton
Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom.
Martin A
MA
Denvir
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D009223:Myotonic Dystrophy / Q000473:pathology*; D065636:Myotonin-Protein Kinase / Q000235:genetics; D019210:Troponin I / Q000097:blood*; D018487:Ventricular Dysfunction, Left / Q000097:blood* / Q000175:diagnosis*; D055815:Young Adult
D015415:Biomarkers; C585517:DMPK protein, human; D019210:Troponin I; D065636:Myotonin-Protein Kinase