Session S64.2

Respiratory Rate Derived from Principal Component Analysis of Single Lead Electrocardiogram

P Langley*, EJ Bowers, A Murray

Newcastle University
Newcastle upon Tyne, UK

We present a novel algorithm for deriving the respiratory rate from single lead ECG. The algorithm was tested on a group of healthy volunteers subjected to a range of breathing protocols.
ECG and respiration were measured in 10 subjects while undertaking different breathing patterns. Subjects were asked to breath at controlled rates of 4, 6, 8, 10, 12, 14 breaths per minute (bpm), and also at their natural breathing rate, for a duration of 180 s. ECG lead II and respiration, via magnetic displacement measurements of chest movement, were recorded. Each ECG beat was detected and principal component analysis applied to the collection of all beats which were aligned to the peak of the R wave. FFT of the coefficients of the first principal component provided the estimate of respiratory rate derived from the ECG. We compared the respiratory rate derived from the ECG with that derived from FFT analysis of the respiratory signal.
Subjects fo 86 llowed the requested controlled breathing patterns closely with mean (sd) rates of 3.97 (0.11), 5.97 (0.11), 7.94 (0.15), 9.87 (0.17), 4B8 11.90 (0.16) and 13.90 (0.16) bpm. Mean (sd) absolute differences between reference respiratory rate and ECG respiratory rate were 0.21 (0.09), 0.19 (0.06), 0.18 (0.03), 0.18 (0.06), 0.12 (0.05) and 0.11 (0.07) bpm for each of the controlled breathing patterns respectively. For natural breathing the rate ranged from 7 to 15 bpm between subjects and the mean (sd) absolute difference between reference and ECG respiratory rate was 0.17 (0.14) bpm.

(Abstract Control Number: 89)