njit-etd2003-081 - New Jersey Institute of Technology

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Figure 5.61 presents a principal component plot of the data set containing 47
COPD at rest and 8 normal subjects at 50%, 75% and 100% load. The data set gave the
following principal components (PC):
1 st PC: rsp — The respiration rate.
2nd PC: HF _ coh_ HR_ BP — Coherence of HR and BP IIBI signals in the HF range
(0.15 - 0.4 Hz).
3 rd PC: HF_pcoh_HR_BP — Partial Coherence of HR and BP IIBI signals in the
HF range (0.15 - 0.4 Hz).
This indicated that the largest variance between COPD at rest and normal subjects
during exercise was the breathing rate (respiration). The second largest variance was the
interrelationships between HR and blood pressure in the HF range. The third largest
variance was the partial interrelationships between HR and blood pressure in the HF
range. The 1 st PC of the respiration indicated that the higher breathing rate of the COPD
subjects was not the same in the HRV sense even though normal subjects increased their
respiration rate to a similar level. Once the respiration PC was removed, the residual
interrelationship was that between HR and blood pressure in the HF range.