Coupling between short-term heart rate and diastolic period is reduced in heart failure patients as indicated by multivariate entropy analysis

The analyses of cardiac dynamics appear to be very promising in assessing cardiovascular health. Short-term analysis well meets the increasing clinical needs for point-of-care diagnosis, portable monitoring and personal healthcare. In one of our previous CinC articles, we have shown that there is inherent coupling between short-term heart rate variability (HRV) and diastolic period variability (DPV). Besides, the coupling is reduced at their small temporal scales in healthy aging subjects. We thus aimed to investigate the HRV-DPV coupling in heart failure (HF) patients in this work. Fifty healthy volunteers and 52 HF patients were studied. Multiscale multivariate fuzzy entropy (MMFE) analysis was performed in each bivariate signal (short-term HRV and simultaneous recorded DPV) to probe into their within- and cross-channel correlations. Results show that the coupling between short-term HRV and DPV is reduced at both small and large temporal scales in HF patients compared with healthy volunteers. It may indicate that the heart loses both the immediate mechanical response to the changes of heart period and its long-range compliance, which is very different from the effects of healthy aging. It thus shows great potential of short-term HRV-DPV coupling analysis in the noninvasive and nondestructive detection of HF. An increased specificity of the so-constructed HF detection indices should also be expected.