1 Symbolic Dynamics-a Powerful Tool in Non-Invasive Biomedical Signal Processing

Heart rate variability (HRV) and blood pressure variability (BPV) reflect the complex interactions of many different control loops of the cardiovascular system. In relation to the complexity of the sinus node activity modulation system, a more predominantly non-linear behavior has to be assumed. In this way the detailed description and classification of dynamic changes using time and frequency measures is often not sufficient. Therefore, we have introduced new methods of non-linear dynamics, especially from symbolic dynamics to distinguish between different states of the autonomic interactions. We demonstrate that parameters obtained from symbolic dynamics are useful for risk stratification after myocardial infarction, for characterization of different cardiovascular diseases and for phenotyping in genetic studies.