Quantifying the causal strength of multivariate cardiovascular couplings with momentary information transfer

The article introduces an information-theoretic approach to detect and quantify causal couplings in the complex cardiovascular system. In a first step a causal algorithm detects the coupling delays and in a second step the causal strength of each coupling mechanism is quantified using the recently introduced momentary information transfer. As a preliminary example, the method is applied to time series of respiration, systolic and diastolic blood pressure, and heart rate of pregnant healthy women and women suffering from pre-eclampsia. A possible explanation for the influence of heart rate on systolic blood pressure is found.