Contributions
Abstract: P352
Type: Poster
Abstract Category: Clinical aspects of MS - Clinical assessment tools
Background: The mechanism whereby cardiac autonomic dysfunction relates to prognosis and extent of disease in Multiple Sclerosis (MS) is unclear. Measures of baroreceptor sensitivity (BRS) provide a means to quantify cardiovascular control mediated by autonomic tone.
Aims: To assess differences in short-term beat-to-beat non-invasive BRS, as well as heart rate variability (HRV) and systolic blood pressure (SBP) variability, in MS subjects compared with age and sex matched controls.
Methods and results: 46 subjects (23 MS, 23 controls) were studied using a finger cuff pressure device (Edwards Nextfin®). 5 minute recordings of heart rate and blood pressure (BP) were obtained and BRS curves derived by sequence techniques and spectral methods. Vasomotor parameters, HRV, biometrics, electrocardiograms, time-based HRV and power spectral analysis (PSA) of HRV at very low frequencies (VLF< 0.04 Hz), low frequencies (LF 0.04 - 0.15 Hz) and high frequencies (HF 0.15 - 0.4 Hz) were measured. BRS by frequency technique is calculated by the square root of power spectral density of HRV/power spectral density of SBP variability which is termed Modulus. The average of this Modulus in each frequency band is termed the alpha index. Coherence between SBP variability and HRV was measured and the average calculated for each frequency band. The average age in the MS group was 38±12 years, 15 were females, and average disease duration was 10±8 years. The average age in the control group was 38±12 years (15 females).
For a combined set of 65 variables and autonomic function parameters, the Mann-Whitney U Test was used to compare inter-group differences, and Chi-squared for comparison of proportions, with significance set at p< 0.05. Multinominal Logistic Regression (MATLAB) was applied to 10 parameters identified to be significantly different between the groups on univariate analysis. After multivariate analysis, two independent variables emerge: BRS spectral frequency by ≥0.5 coherence (p=0.04) and mean Modulus of HF frequency variability of systolic BP (p=0.04).
Conclusions: Systemic autonomic function analysis demonstrates that spectral BRS and spectral SBP distinguish MS patients from age and sex matched controls. These results suggest that BRS and BP analysis by PSA techniques provide a potential method to monitor patients with MS.
Disclosure:
E Barin: nothing to disclose.
F Shirbani: nothing to disclose.
YC Lee: nothing to disclose.
A Fontes-Villalba: has received educational sponsorship from Merck Serono and Genzyme..
K Ng: nothing to disclose.
JDE Parratt: nothing to disclose
M Butlin: nothing to disclose.
A Avolio: nothing to disclose.
Abstract: P352
Type: Poster
Abstract Category: Clinical aspects of MS - Clinical assessment tools
Background: The mechanism whereby cardiac autonomic dysfunction relates to prognosis and extent of disease in Multiple Sclerosis (MS) is unclear. Measures of baroreceptor sensitivity (BRS) provide a means to quantify cardiovascular control mediated by autonomic tone.
Aims: To assess differences in short-term beat-to-beat non-invasive BRS, as well as heart rate variability (HRV) and systolic blood pressure (SBP) variability, in MS subjects compared with age and sex matched controls.
Methods and results: 46 subjects (23 MS, 23 controls) were studied using a finger cuff pressure device (Edwards Nextfin®). 5 minute recordings of heart rate and blood pressure (BP) were obtained and BRS curves derived by sequence techniques and spectral methods. Vasomotor parameters, HRV, biometrics, electrocardiograms, time-based HRV and power spectral analysis (PSA) of HRV at very low frequencies (VLF< 0.04 Hz), low frequencies (LF 0.04 - 0.15 Hz) and high frequencies (HF 0.15 - 0.4 Hz) were measured. BRS by frequency technique is calculated by the square root of power spectral density of HRV/power spectral density of SBP variability which is termed Modulus. The average of this Modulus in each frequency band is termed the alpha index. Coherence between SBP variability and HRV was measured and the average calculated for each frequency band. The average age in the MS group was 38±12 years, 15 were females, and average disease duration was 10±8 years. The average age in the control group was 38±12 years (15 females).
For a combined set of 65 variables and autonomic function parameters, the Mann-Whitney U Test was used to compare inter-group differences, and Chi-squared for comparison of proportions, with significance set at p< 0.05. Multinominal Logistic Regression (MATLAB) was applied to 10 parameters identified to be significantly different between the groups on univariate analysis. After multivariate analysis, two independent variables emerge: BRS spectral frequency by ≥0.5 coherence (p=0.04) and mean Modulus of HF frequency variability of systolic BP (p=0.04).
Conclusions: Systemic autonomic function analysis demonstrates that spectral BRS and spectral SBP distinguish MS patients from age and sex matched controls. These results suggest that BRS and BP analysis by PSA techniques provide a potential method to monitor patients with MS.
Disclosure:
E Barin: nothing to disclose.
F Shirbani: nothing to disclose.
YC Lee: nothing to disclose.
A Fontes-Villalba: has received educational sponsorship from Merck Serono and Genzyme..
K Ng: nothing to disclose.
JDE Parratt: nothing to disclose
M Butlin: nothing to disclose.
A Avolio: nothing to disclose.