Digital signal analysis of cardiac events in horses and ponies.

We have developed a digital signal analysis technique which can be used to evaluate various cardiac events in ponies and horses at rest and during exercise. The algorithm is designed to identify R-wave peaks on the surface electrocardiogram, consistent reference points on the left ventricular pressure waveform and the initiation of the QRS complex on the epicardial electrogram. We have used the technique to evaluate data from 10 horses and ponies at rest, during strenuous exercise and during experimentally-induced coronary artery occlusion. The technique provided rapid and accurate beat-by-beat evaluation of data, even with relatively noisy signals and under conditions in which the waveform configurations were not consistent. The benefits afforded by this technique make it especially useful for extracting information which previously was difficult or impossible to obtain using more conventional methods of analysis.