You are at a concert when suddenly the orchestra stops playing their instruments with the exception of the kettledrums. The kettle drummer hits two beats with a pause. This is repeated over and over as you realize the drumbeats are the heart and rhythm for the orchestra. In your head you can mimic your own heartbeat with valvular doors that slam with distinct thuds and a synchrony of rhythm that is supposed to alert you to any delay in beats or an undeniable rumble of the added percussion that is a sound gone array. These sounds are meaningful, they emanate from your heart, and that of your horse’s, as barometers for the physicians, and veterinarians, to rely on for interpretation of your vital signals to your health status.

The heart functions as a magnificent pump. It fills and empties thousands of times a day. There are four chambers, and when divided into two sides, the left and right sides each perform their functions to transport blood to the cells of the body. The left side of the heart pumps oxygenated blood into the arterial circulation through arteries, arterioles, and capillaries where the oxygen is exchanged and the used blood is returned to the venules, veins, and eventually back to the right side of the heart. The blood then travels from the right side of the heart where it is pumped into the lungs to become re-oxygenated, and the exchanged carbon dioxide waste is expelled through the air. The new oxygen-rich blood is then returned to the left side of the heart and again pumped out into the arterial circulation.

The heart pump does this through its chambers, which are separated by valves while adjusting to different volumes and rates. These changes are signals of pressure and oxygen sensors throughout a complex physiological system that feeds from a network of regulators throughout the body and brain.

The heart should function with a rate and rhythm that is consistent with an overall assessment of your horse’s health. If there is an inconsistency, it does not always mean that your horse’s heart is failing, in fact heart failure in horses is reasonably uncommon. It may mean the heart rate and rhythm is adjusting to other physiological issues such as in stress, exercise, electrolyte abnormalities, shock, toxic insults, and a myriad of circulatory disturbances that may require regulation of heart function