PR and PP ECG intervals as indicators of autonomic nervous innervation of the cardiac sinoatrial and atrioventricular nodes

Two different methods to elucidate the dependent or independent nature of the autonomic nervous system influence on the sinoatrial and atrioventricular nodes are considered. ECG PP and PR intervals are extracted from 20 normal, young healthy subjects using a wavelet based technique. The first analysis technique focuses upon a supine to stand transition. This transient event serves to highlight the uncoupled nature of PP and PR interval duration for about five beats, suggesting an independent ANS drive to each node. Secondly, sections of quiet supine and standing data are analyzed. Parametric spectral analysis shows variable LF and HF component behavior across different subjects. The relative distribution of recovery RP intervals versus PR for supine and standing are clearly separate for 10 different subjects and borderline for 5. Large intersubject variation is evident.