Common non-invasive diagnostic methods like Holter monitoring or the analysis of high-resolution ECG and heart rate variability are unable to accurately assess the individual risk for sudden cardiac death, since they describe only statistical, linear or strictly periodic parameters. Using new methods of non-linear dynamics one can now calculate parameters which much better describe the dynamic behaviour of complex systems. The application of these new methods should therefore lead to an improved identification of high-risk patients. The results of this first pilot investigation show on the one hand that ventricular arrhythmias are quick detectable using phase space plots, and on the other hand that the new methods of non-linear dynamics could lead to a new classification of high-risk patients.