4.1.2 Equipment
4.1.2 Equipment

Equipment suitable for recording ECGs in horses is readily available and relacheap. Because the principal purpose of recording ECGs is to evaluate the cardiac rhythm rather than examine complex size and conformation in different leads, a single-channel machine is ideal. These are now small and light enough to be held in one hand. They are usually battery powered so they can be used in the horse's stable, or even used where the animal is exercised. The only advantage to using a multi-channel machine is that movement artefacts, which may be evident on two leads only, might be misinterpreted as an abnormal complex when only one channel is recorded. Multi-channel recordings can also be useful in the rare situation when a clear P wave is not seen using the bipolar leads commonly used in the horse (see below), in which case a different lead system may show the waveform more clearly. However, in the vast majority of cases, a singlehead recording is all that is required.

A large number of single-channel machines are available. Unfortunately the clips supplied by the manufacturer are often inadequate and it is worth pursilver-nickel crocodile clips, filing down the teeth and bending the jaws so that they are atraumatic but still remain firmly attached to the horse. Spare leads can be taped together so that they do not tangle. Careful storage of the recording is advisable because it will spoil if it is allowed to get wet or is exposed to direct sunlight. Envelopes provide a cheap and convenient filing method.