Multifractal and nonlinear assessment of autonomous nervous system response during transient myocardial ischaemia

We assess autonomic nervous system response during prolonged percutaneous transluminal coronary angioplasty (PTCA) using heart rate variability analysis with multifractal indices. These indices are used to evaluate the effects of the PTCA procedures at different arteries and locations. A total of 55 patients from the Staff3 database, with no prior history of myocardial infarction, were included in the study. The indices increased significantly during the transient ischaemia and reperfusion periods, indicating an increase in nonlinear multifractal characteristics and a change in temporal correlations in heartbeat fluctuations. This indicates that significant multifractal and nonlinear complex reactions in the autonomic control of the heart rate occurred during coronary artery occlusions and suggests that the multifractal indices may be a promising nonlinear technique for evaluating autonomic nervous system response in the presence of transient myocardial ischaemia.