The controllability of cardiac rhythm in elderly

Introduction: Recent reports have shown that rare fluctuations in cardiac cycles are ‘forgotten’ quickly in healthy individuals and it is possible to quantify the “memory length” of a physiological time-series using an inverse statistical approach. Methods: In the present study, we assessed the effect of aging on memory length in cardiac rhythm. Results: There was a longer memory length in cardiac time-series of elderly subjects in comparison with younger adults for both decelerating and accelerating rare fluctuations in cardiac rhythm. Conclusion: The increased memory length of the cardiac time-series in elderly subjects may indicate reduced controllability of cardiovascular regulatory system.