Good reproducibility of heart rate variability after orthostatic challenge in patients with a history of acute coronary syndrome.
BACKGROUND
Several parameters of heart rate variability (HRV) have been shown to predict the risk of sudden cardiac death (SCD) in cardiac patients. There is consensus that risk prediction is increased when measuring HRV during specific provocations such as orthostatic challenge. For the first time, we provide data on reproducibility of such a test in patients with a history of acute coronary syndrome.


METHODS
Sixty male patients (65 ± 8 years) with a history of acute coronary syndrome on stable medication were included. HRV was measured in supine (5 min) and standing (5 min) position on 2 occasions separated by two weeks. For risk assessment relevant time-domain [standard deviation of all R-R intervals (SDNN) and root mean squared standard differences between adjacent R-R intervals (RMSSD)], frequency domain [low-frequency power (LF), high-frequency power (HF) and LF/HF power ratio] and short-term fractal scaling component (DF1) were computed. Absolute reproducibility was assessed with the standard errors of the mean (SEM) and 95% limits of random variation, and relative reproducibility by the intraclass correlation coefficient (ICC).


RESULTS
We found comparable SEMs and ICCs in supine position and after an orthostatic challenge test. All ICCs were good to excellent (ICCs between 0.636 and 0.869).


CONCLUSIONS
Reproducibility of HRV parameters during orthostatic challenge is good and comparable with supine position.
Preventive Cardiology and Sports Medicine, University Clinic for Cardiology, Inselspital, University Hospital of Berne, Switzerland.
Daniela
D
Schäfer
Preventive Cardiology and Sports Medicine, University Clinic for Cardiology, Inselspital, University Hospital of Berne, Switzerland; Institute for Human Movement Sciences, ETH Zurich, Exercise Physiology, Zurich, Switzerland.
Markus
M
Nil
Preventive Cardiology and Sports Medicine, University Clinic for Cardiology, Inselspital, University Hospital of Berne, Switzerland.
David
D
Herzig
Preventive Cardiology and Sports Medicine, University Clinic for Cardiology, Inselspital, University Hospital of Berne, Switzerland.
Prisca
P
Eser
Preventive Cardiology and Sports Medicine, University Clinic for Cardiology, Inselspital, University Hospital of Berne, Switzerland.
Hugo
H
Saner
Preventive Cardiology and Sports Medicine, University Clinic for Cardiology, Inselspital, University Hospital of Berne, Switzerland. Electronic address: matthias.wilhelm@insel.ch.
Matthias
M
Wilhelm
D054058:Acute Coronary Syndrome / Q000175:diagnosis* / Q000503:physiopathology*; D000368:Aged; D004244:Dizziness / Q000175:diagnosis / Q000503:physiopathology; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D056888:Patient Positioning / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013575:Syncope / Q000175:diagnosis* / Q000503:physiopathology*
Autonomic nervous system; Coronary artery disease; Ectopic beat; Orthostatic test; Risk assessment