Autonomic nervous system response during coronary occlusion evaluated with multiple factor analysis of standard and fractal indexes

The purpose of this study was to characterize the autonomic nervous system changes during a prolonged percutaneous transluminal coronary angioplasty (PTCA) procedure. This study used the records of 61 procedures from the Staff-3 database. Four stages were considered: 2 min of the pre-inflation ECG period; the first 2 min and last 2 min of the ECG during occlusion and 2 min immediately after balloon deflation. Standard and Fractal Indexes parameters from HRV analysis were extracted for each stage. Results show that the most important variables for the construction of the first axis were rMSSD and HF. The construction of the second axis depends mainly on the LF/(LF+HF) and fractal scalar exponent alfa-1. Results show that sympathetic activity increases during and after PTCA, and parasympathetic activity and complexity of ANS decreases during PTCA and increases in post-PTCA.