Phase-Recti†ed Signal Averaging: Methods and Clinical Applications

The assessment of heart rate variability (HRV) offers a glimpse into the operation of the autonomic nervous system. One characteristic of a healthy autonomic nervous system is the ability of an organism to adjust its heart rate to changing demands. Because the events that trigger changes in the heart rate are not necessarily correlated with each other, the heart rate signals are quasiperiodic; they consist of periodic patches that are not in phase CONTENTS 6.1 Introduction .......................................................................................................................... 87 6.2 Methods .................................................................................................................................88