Nonlinear dynamics versus traditional methods of heart rate variability analysis

Non-linear changes in the heart rate are often not detectable using traditional methods of heart rate variability analysis in the time and frequency domain. Therefore the authors have tried to quantify them applying new methods of non-linear dynamics. Ten cardiac patients after myocardial infarction (MI) with a low electrical risk, 16 cardiac patients after MI with a high electrical risk, 13 patients with different cardiac diseases and 22 healthy persons have been investigated. The detection rate of parameters from the time domain was 30% of patients in the low risk and 43% in the high risk group. The frequency analysis produced a ratio of 40/69% and the result from non-linear dynamics was 40/75 %. The combination of methods in the frequency domain and non-linear dynamics led to an increased detection rate of high risk patients of 88%