Abstract

Regulatory synchronization between the heart and the arterial walls is essential for optimal blood delivery to tissues. We investigated functional coherence between heart rhythm and aortic wall compliance in 30 volunteers aged 65 – 74. ECG and carotid and iliac pulse-wave were recorded and digitized at 2 kHz. Carotid-femoral pulse-wave transit time (cfTT) which reflex aortic compliance was assessed using the intersecting tangent algorithm at time-point of the maximal upstroke of the second derivative of the filtered pulse signal. Time-series of 256 heart cycles were used for heart rate variability (HRV) and cfTT variability analysis. Averaged power spectral density (aPSD) was estimated within selected frequency ranges by fast Fourier transform (FFT) approach. Magnitude squared coherence (MSC) between the both spectra was estimated. All volunteers exhibited variable temporal patterns of both HRV and cfTT variability. aPSD was reduced along with decreasing of time-window from 60 to 240 s. High coherent states between HRV and cfTT variability were observed as a short time prominent MSC peaks in almost all participants. Individual patterns of irregular MSC changes in time but not a generalized model of its fluctuations seem to reflect dynamic functional interaction between the heart and aortic compliance at an advanced age.

Authors (5)