Heart rate variability in sarcoidosis: A frequency domain analysis

Little is known about autonomic dysfunction in patients with sarcoidosis. Heart rate variability (HRV) studies provide information regarding sympathetic and vagal tone and are both noninvasive and relatively simple to perform. The objective of this study was to compare HRV in sarcoidosis patients and in healthy controls. We prospectively analyzed data from 12 sarcoidosis patients and 12 healthy volunteers. Electrocardiographic (ECG) data were recorded from all study participants, and HRV analysis was performed in the frequency domain. The sarcoidosis patients underwent echocardiography as well. Mean values for HRV in the high-frequency (HF) domain were significantly reduced in sarcoidosis patients (182±102 ms² vs. 758±457 in controls, p=0.001). We also observed a trend (p=0.055) towards an increased ratio of low-frequency (LF) to high-frequency power in sarcoidosis patients. Our findings indicate the possibility of altered sympathovagal balance in sarcoidosis. Since 5 of these 12 sarcoidosis patients had mild echocardiographic abnormalities, possibly related to sarcoidosis, we were unable to conclude whether the HRV findings were attributable solely to an autonomic dysfunction in sarcoidosis or whether they were related to a structural myocardial involvement of the disease.