Objective: Autonomic dysfunction has been described in scleroderma. Heart rate variability gives information about sympathetic-parasympathetic autonomic balance, therefore it can provide insight into which division of the system is most affected. Our purpose was to determine whether the neural control of heart rate in patients with CREST syndrome differed from that in patients with diffuse scleroderma. Since low heart rate variability in some diseases is associated with an increased risk for malignant ventricular arrhythmias, assessment of patients with scleroderma with this technique might establish a marker of adverse outcome.
Methods: A short time analysis of heart rate variability was performed in 9 patients with diffuse scleroderma, 8 with CREST and 17 age/sex matched healthy controls.
Results: An abnormal heart rate variability was found in patients with CREST: There was a reduced standard deviation of the mean of beat-to-beat R-R intervals and a low power spectrum density in both the 0.05 to 0.15 Hz band and the 0.15 to 0.35 Hz band, a significant reduction in their total power (p < 0.05), a reduction in the high frequency to total power ratio (p < 0.05), and a reduction in the ratio between high and low frequency components of their spectrum.
Conclusion: It is suggested that patients with CREST have a decreased parasympathetic control of heart rate, significantly different from those with diffuse disease. Whether this finding is pertinent to the differences between these subsets of patients remains to be established.