Long- and short-term analysis of heartbeat sequences: Correlation with mortality risk in congestive heart failure patients

We analyze RR heartbeat sequences with a dynamic model that satisfactorily reproduces both the long- and the short-time statistical properties of heart beating. These properties are expressed quantitatively by means of two significant parameters, the scaling concerning the asymptotic effects of long-range correlation, and the quantity 1– establishing the amount of uncorrelated fluctuations. We find a correlation between the position in the phase space (,) of patients with congestive heart failure and their mortality risk.