Abstract P91: Prognostic and Pathophysiological Significance of Heart Rate Variability Indices in Intensive Care Patients with Cardiovascular Complication: Its Relation with APACHE Prognostic Score and Cytokines
Background: Heart rate variability indices (HRV) are prognostic marker in cardiovascular diseases. However, the prognostic value and pathophysiological role of HRVs in intensive care patients (ICU-pts) are not fully investigated. We compared HRVs [including non-linear index of long-term fractal â(fractal-â)] with Acute Physiologic and Chronic Health Evaluation III Score (APACHE III) and serum cytokine levels. The former is well-known prognostic index and the latter is indices reflecting various pathophysiological conditions in ICU-pts.
Methods: HRVs were obtained from 24-hour ECG monitoring in 80 ICU-pts including 27 post-surgical pts with cardiac complications (67±8 years old) and 53 pts with acute coronary syndrome (65±13 years old). APACHE III was calculated and blood samples were obtained for cytokine measurement by ELIZA method at the time of pts admission to ICU. Cytokines that we measured were IL-1â, IL-4, IL-6, IL-8, IL-10, IL-12 (p70), IL-13, IL-15, IL-17, G-CSF, INFã, TNFá and MIP-1á. HRVs included fractal-â and mean-HR, SDANN, SD-index, pNN50, rMSSD, total frequency spectra (TF), very low frequency spectra (VLF), low frequency spectra (LF), high frequency spectra (HF) and LF/HF ratio
Results: Among HRVs, rMSSD and pNN50 correlated with APACHE III, respectively (r=0.29 and r=0.23, p<0.05). On the other hand, fractal-â correlated with IL-13 and INF-ã(r=0.26 and r=0.26, p<0.05) while mean-HR correlated with IL-8 (r=0.27, p<0.05) and SD-index with INF-ã and TNFá (r=0.33, p<0.01 and r= 0.28, p<0.05). In addition, TF correlated with IL-12 (p70) (r=0.35, p<0.01) and VLF correlated with IL-12 (p70) and INF-ã (r=0.26, p<0.05 and r=0.39, p<0.001) while LF with IL-12 and INF-ã (r=0.25 and r=0.25, p<0.05) as well as LF/HF ratio with IL-1â, IL-4, IL-13 and IL-8 (r=0.23, r=0.24, r=0.24 and r=0.28, p<0.05). IL-8 correlated with APACHE III (r=0.30, p<0.01).
Conclusions: Among HRVs and cytokines, rMSSD, pNN50 and IL-8 are associated with the prognosis and many HRVs reflect various immune and inflammatory state in ICU. Measuring HRVs gives us prognostic and pathophysiological information in ICU-pts with cardiac complications.