Before a treadmill test the horse must be fitted with the proper equipment. The horse wears a safety harness to prevent it from falling down for any reason during the test. Protective shin guards are placed on the lower forelegs, and boots are placed on all four hooves to prevent the horse from injuring itself during high speeds. If the horse is a Standardbred pacer, hobbles are placed on the legs to maintain a pacing gait. If an electrocardiogram is to be done then electrodes are placed under the harness to record the electrical activity of the heart.
The treadmill test is used in veterinary medicine for many reasons. It is used in horses to diagnose lameness, detect cardiovascular and respiratory abnormalities, and determine reasons for decreased performance. Heart and respiratory rates can be monitored as well as other physiological functions. The horse can have an endoscopy examination of the upper airways during exercise and can have electrodes placed for an ECG during the test. A catheter can also be placed to monitor arterial blood gas during exercise. The treadmill can be increased up to 30 mph and can also be set at different inclines (6% or 10%) to increase intensity at lower speeds.
Collection of Arterial Blood
An arterial catherer can also be placed in the facial artery prior to the treadmill test to allow for blood collection during the test.
An arterial catherer placed in the facial artery allows blood to be drawn during the treadmill test to monitor arterial blood. Arterial blood gas and lactate concentrations are examples of what is commonly measured using an arterial catherer.
An electrocardiogram is used to record the electrical activity of the heart. The electrical waves are measured by electrodes placed on the skin. Electrode gel is placed between the electrode and the skin to increase conduction and provide better contact to the skin. The ECG can be used to measure and diagnose abnormal heart rhythms.
Upper Airway Endoscopy
Endoscopy is a minimally invasive medical procedure using a video endoscopy system to view the interior of a hollow organ or part, such as the upper airways. The upper airways of the horse are from the nose through the nasal passages to the larynx. Endoscopy during the treadmill test is used to visualize the larynx to diagnose possible causes of exercise intolerance such as displacement of the soft palate, epiglottic entrapment, and laryngeal hemiplegia.