In juvenile dermatomyositis, heart rate variability is reduced, and associated with both cardiac dysfunction and markers of inflammation: a cross-sectional study median 13.5 years after symptom onset.
OBJECTIVE
Low heart rate variability (HRV) is a well-established predictor of cardiac death. The aim of this study was to investigate arrhythmias and HRV in patients with JDM, and associations between HRV and inflammatory markers, echocardiographic measurements and disease parameters.


METHODS
Fifty-five patients with JDM were examined 2-34 years (median 13.5 years) after disease onset, and compared with 55 age and sex matched controls. Holter ECG monitoring and echocardiography were analysed blinded to patient information. Arrhythmia and HRV (six parameters) were analysed by standard software, finally adjudicated by an experienced cardiologist. Markers of inflammation (ESR, high sensitivity (hs)CRP and cytokines) were analysed. Disease activity and organ damage were assessed by clinical examination at follow-up and retrospectively by chart review.


RESULTS
In two out of six HRV parameters, JDM patients had lower values than controls. No difference in arrhythmias was found between the groups. In patients, but not in controls, there were significant negative correlations between five out of six HRV parameters, and ESR and hsCRP (Spearman correlation coefficient, -0.306 to -0.470; P, 0.023 to <0.001). Also, in patients, negative correlations were found between three out of six HRV parameters and systolic and diastolic function. Active disease and low HRV were associated. Patients with hsCRP in the highest quartile (Q4) had lower HRV in all parameters compared with those in pooled Q1-3 (P < 0.001).


CONCLUSIONS
JDM patients had reduced HRV, which was associated with elevated inflammatory markers, active disease and reduced myocardial function. This suggests reduced vagal control of the heart; further studies are needed to determine whether this is also associated with cardiac morbidity or mortality.
Institute for Experimental Medical Research, Oslo University Hospital-Ullevål and University of Oslo, Oslo, Norway, Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Pécs, Hungary, Department of Health sciences, Bjørknes College, Oslo, Norway.
Zoltan
Z
Barth
Institute for Experimental Medical Research, Oslo University Hospital-Ullevål and University of Oslo, Oslo, Norway.
Birgit
B
Nomeland Witczak
Institute for Experimental Medical Research, Oslo University Hospital-Ullevål and University of Oslo, Oslo, Norway, Institute for Clinical Medicine, Medical Faculty, University of Oslo, Oslo, Norway, Section of Rheumatology, Oslo University Hospital-Rikshospitalet, Oslo, Norway and.
Thomas
T
Schwartz
Institute for Clinical Medicine, Medical Faculty, University of Oslo, Oslo, Norway, Department of Cardiology, Oslo University Hospital-Ullevål, Oslo, Norway.
Knut
K
Gjesdal
Institute for Clinical Medicine, Medical Faculty, University of Oslo, Oslo, Norway, Section of Rheumatology, Oslo University Hospital-Rikshospitalet, Oslo, Norway and.
Berit
B
Flatø
Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Pécs, Hungary.
Akos
A
Koller
Section of Rheumatology, Oslo University Hospital-Rikshospitalet, Oslo, Norway and.
Helga
H
Sanner
Institute for Experimental Medical Research, Oslo University Hospital-Ullevål and University of Oslo, Oslo, Norway, Department of Cardiology, Oslo University Hospital-Ullevål, Oslo, Norway ivar.sjaastad@medisin.uio.no.
Ivar
I
Sjaastad
D000293:Adolescent; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000453:epidemiology*; D002097:C-Reactive Protein / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D016207:Cytokines / Q000097:blood*; D003882:Dermatomyositis / Q000453:epidemiology* / Q000503:physiopathology; D015150:Echocardiography, Doppler; D015716:Electrocardiography, Ambulatory / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D008297:Male; D009205:Myocarditis / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D009664:Norway; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000453:epidemiology*; D055815:Young Adult
D016207:Cytokines; D018836:Inflammation Mediators; D002097:C-Reactive Protein
arrhythmia; autonomic impairment; cardiac dysfunction; echocardiography; heart rate variability; juvenile dermatomyositis; paediatric rheumatology