Ischaemic cardiomyopathy is a common disease which may lead to sudden cardiac death (SCD). By the help of angioplasty, a stent can prevent an ischemia by blood vessel extension. The purpose of this study is to predict which patients have a higher risk to suffer from heart failure although they have a transplanted stent. This medical device is a small mesh tube that can open occlusions especially in coronary vessels. But in some cases restriction of blood flow through an adjacent branch of a blood vessel occurs. This report focuses on the investigations of the analysis of samples of real beat-to-beat intervals from patients with congestive heart failure (CHF). A data set of 64 ischaemic cardiomyopathy patients with an implanted stent and the risk of sudden cardiac death have been studied. To characterize these data the difference between high risk (HR) and low risk (LR) patient groups was calculated by nonlinear analysis, symbolic dynamics and the entropy as a measure of information content. By means of nonlinear and statistical analyses e.g. Mann- Whitney-Wilcoxon test (MWW) and the leave-one-out cross-validation (LOOCV) a distinction between HR- and LR patients could be made. It was found that in short RR series the analysed entropy shows rather slight but significant differences between the HR and LR group in contrast to the entropies of long RR series. But only appointed parameters from the symbolic dynamics as well as the nonlinear dynamics are able to distinguish significantly both groups. This method would be helpful to improve the diagnosis of ischemic cardiomyopathy and would facilitate an immediate treatment in case of a higher risk of sudden cardiac death.

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