DFA(detrended fluctuation analysis)フラクタル特性の臨床的意義 : 地域存在高齢者と心臓移植患者での検討

概要

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Fractal analysis of heart rate variability (HRV) is a new approach to evaluating the risk of mortality in various patient groups. We examined the prognostic power of detrended fluctuation analysis (DFA) of HRV in 298 elderly community-dwelling subjects (79.6 years) and 15 patients (23.3 years) who had undergone human heart transplantation (HTx). Short-term (<11 beats, α_1) and longer-term (>11 beats, α_2) scaling exponents were determined using the DFA method. First, a Cox regression analysis disclosed a significant association with all-cause mortality in the elderly group. After adjustments for both sex and age, a 0.2-unit increase in a2 was found to be associated with an RR of 0.61 (95% confidence interval: 0.42 to 0.90, p<0.05). Second, α_1 was markedly smaller (0.599 ± 0.062 vs 1.052 ± 0.117, p<0.005) and α_2 was larger (1.075 ± 0.088 vs 0.911 ± 0.070, p<0.05) in the HTx group, compared with 50 age-matched healthy subjects, and circadian variations were absent among the HTx patients. A patient who later experienced sudden cardiac death 5 years after an HTx showed a prominent morning dip in α_2 compared with 4 other HTx patients who survived. These findings suggest DFA scaling components may provide powerful prognostic information in both elderly subjects and HTx patients.
東京女子医科大学の論文