Analysis of right ventricular function in the exercising horse: use of theFourier Transform

The objective of this study was to develop and test a technique to allow dy namic cardiac function to be studied during exercise in the horse. Blood pr essure waveforms in the exercising horse are difficult to interpret because of the large influence of stride and respiration. A method has been devise d to study dynamic right ventricular variables during high-speed exercise i n the horse. A Fast Fourier Transform was performed on the digitised pressu re waveforms and the frequency components associated with stride and respir ation were removed. An inverse Fourier Transform was then performed to gene rate a time-domain pressure signal. Several dynamic right ventricular varia bles were calculated using the derived signal. Various parameters associate d with removing frequencies from the frequency-domain pressure signal were changed to determine their influence on the variables. Most of the variable s were not sensitive to these parameters. When compared during separate exe rcise bouts, some variables differed among runs, while others were not sign ificantly different. Using the signal separation technique described here, right ventricular function of an exercising horse can be critically analyse d.