Detrended Fluctuation Analysis (DFA) of Heart Rate Fluctuations and Its Clinical Use of Heart Rate Variability in Elderly Community-Dwelling People and in Patients with Transplanted Human Hearts

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_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