UBC Theses and Dissertations
Inter-individual and intra-individual variations of the phase plane measurements of the brachial pulse wave Whittaker, Sharon Anne
The purpose of this study was to determine the reproducibility of selected phase plane loop measurements of the brachial pulse wave for possible use in future assessment of cardiovascular condition. It was hypothesized that any intra-individual or within subject variation would be small in relation to the inter-individual variability in the measurements of a subject on the four testing occasions. The brachial artery pressure pulse, first derivative, and phase plane loop were projected onto the oscilloscope screen and photographs were taken. The exercise was a five minute stepping test at thirty steps per minute on a seventeen inch bench and photographs were taken of the pressure pulse, first derivative, and phase plane loop, at rest, immediate post exercise, five minutes post exercise, and ten minutes post exercise. Selected measurements on the phase plane loop photographs were PQ, ṖQ, PR, ṖR, ṖQ/ṖR, Pr/Ṗ r. Resting heart rate (beats/minute), first (1-1:30 minutes) recovery heart beat count, second (2-2:30 minutes) recovery heart beat count, third (3-3:30 minutes) recovery heart beat count, and total recovery heart beat count values were also recorded. An analysis of variance was performed on each of the twenty-nine measurements and reliability coefficients were calculated for each measurement. A between subjects variability F-ratio was calculated, giving an indication of true score variation or inter-individual variation. The F-ratio for between trials variation was also calculated to give an indication of any 'effect' due to trials. There was seen to be no systematic trend of the data over the four trials. The F-ratios for between subjects variability were generally seen to be significant at the .05 level. The inter-individual differences were found to be large in comparison to intra-individual differences. The reliability coefficients for resting heart rate (beats/minute), first recovery heart beat count, second recovery heart beat count, third recovery heart beat count, and total recovery heart beat count were all over .900, showing good reproducibility. The reliability coefficients for measurements PQ and PR were all quite low, whereas, the reliability coefficients for measures ṖQ and ṖR were all quite high, indicating that these measures were reproducible. The ratios ṖQ/ṖR and Pr/Ṗr also had generally high reliability coefficients, showing good reproducibility of these measures. Of the six variables (PQ, ṖQ, PR, ṖR, ṖQ/ṖR, Pr/Ṗr) selected, only two (PQ and PR did not show good reproducibility.
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