Asymmetry of haemodynamic variability in healthy people

Heart rate asymmetry is caused by an unequal contribution of heart rate decelerations and accelerations to the heart rate variability, structure and complexity. Here we show that the variability of different haemodynamic parameters such as stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) has asymmetrical properties. For this purpose we used 30-minute cardiac impedance recordings with beat-to-beat values of SV, CO and SVR from 99 healthy young volunteers. The increases of haemodynamic parameters present significantly different contributions to the short-term, long-term and total variability as well as the number of such increases is different from decreases. Haemodynamics such as SV, CO and SVR are additional examples of cardiovascular time series presenting asymmetrical properties of their variability. Our results suggest that asymmetry of cardiovascular time series is rather a general physiological phenomenon. The clinical value of these findings requires further investigation.