Original Paper Cerebrovasc Dis 2003;16:151–157 DOI: 10.1159/000070595 Noninvasive Assessment of Spontaneous Baroreflex Sensitivity and Heart Rate Variability in Patients with Carotid Stenosis A.C. Chao a C.M. Chern c T.B. Kuo b C.H. Chou c Y.M. Chuang c W.J. Wong c H.H. Hu c a Department of Neurology, Kaohsiung Medical University and Hospital, Kaohsiung, b Institute of Neuroscience, Tzu Chi College of Medicine and Humanities, Hualien, c Neurovascular Section, Neurological Institute, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan Received: May 10, 2002 Accepted: October 9, 2002 Han-Hwa Hu, MD Neurological Institute Taipei Veterans General Hospital Taipei 11217 (Taiwan) Tel. +886 2 28757046, Fax +886 2 28739241, E-Mail hhhu@vghtpe.gov.tw ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2003 S. Karger AG, Basel 1015–9770/03/0162–0151$19.50/0 Accessible online at: www.karger.com/ced Key Words Baroreflex sensitivity W Heart rate variability W Carotid stenosis Abstract Background: Previous limited observations have sug- gested that atherosclerosis may affect the distensibility of the carotid sinus and then impair the baroreflex sensi- tivity (BRS). No studies have been done to compare the BRS and heart rate variability (HRV) in patients with carotid stenosis and normal controls. Methods: A conve- nience-consecutive sample of 118 patients with transient ischemic attack or minor stroke 3 months to 1 year before (mean 6 months) who met the study criteria were re- ferred to the neurovascular laboratory of the study hos- pital. Forty-three age-matched healthy adults were re- cruited as the normal controls. The inclusion criteria for participation were (1) no diabetes mellitus, (2) no history, symptoms or ECG signs of coronary artery disease or myocardial infarction, and (3) presence of carotid steno- sis greater than or equal to 50%. The diagnosis of carotid stenosis was made using color-coded duplex ultrasound with published criteria. We categorized the patients into two groups: group 1 had moderate stenosis (50–75%) and group 2 had high-grade stenosis (75–99%). Instanta- neous systolic blood pressure (SBP) and heart rate of all participants were assessed noninvasively using servo- controlled infrared finger plethysmography. The fluctua- tion in SBP as well as the interpulse interval (IPI) was divided into three components at specific frequency ranges by fast Fourier transform as high frequency (HF; 0.15–0.4 Hz), low frequency (LF; 0.04–0.15 Hz) and very low frequency (VLF; 0.004–0.04 Hz). The BRS was ex- pressed as (1) transfer function with its magnitude in the HF and LF ranges, (2) BRS index alpha, and (3) regression coefficient by sequence analysis. The HRV was ex- pressed as total power and power in the three frequency ranges (HF, LF and VLF). Results: The final analysis included 99 patients (mean age 72 B 6 years, 79 male) and 43 healthy controls (mean age 68 B 7 years, 30 male). Forty-three patients were classified as group 1 (stenosis 50–75%) and 56 as group 2 (stenosis 75–99%). There was no significant difference in the IPI between patients and controls (p value = 0.8637). We observed a significant decrease in all three HRV components (VLF,