Nocturnal Frequency Instability of Respiratory Sinus Arrhythmia in Heart Failure

摘要

In heart failure, early detection of exacerbation is required to avoid unnecessary hospitalization. Although respiration instability detected by a respiration sensor attached to the bed at home has been proposed, detection by a more popular general sensor is desired. Using the fact that the frequency of respiratory sinus arrhythmia $(mathrm{F}_{mathrm{RSA}})$ reflects the frequency of breathing $(mathrm{F}_{mathrm{B}})$, we developed a method to estimate the instability of $mathrm{F}_{mathrm{B}}$ by analyzing the instability of $mathrm{F}_{mathrm{RSA}}$ only using R-R interval time series obtained from nighttime ECG. In 69 healthy control subjects, the fluctuation of $mathrm{F}_{mathrm{RSA}}$ reduced to 6.8 $pm 3.9{%}$ of local mean during sleep, while it remained $16.4pm 7.7{%}$ and 17.5 $pm 5.8{%}$ in sinus rhythm patients with heart failure who survived for 38-mo follow-up period after recording (n = 52) and those died during the follow-up $(mathrm{n}=29)$, respectively. $mathrm{F}_{mathrm{RSA}}$ instability detected by ECG during sleep may be used as a feature to screen patients with heart failure.