| The majority of horses with heart murmurs show no | | | | must also be remembered that all of the above signs |
| external signs, as the heart is a very efficient pump | | | | can also be features of other, less serious conditions. |
| that is able to compensate. Problems usually only | | | | What Causes a Murmur? |
| become apparent when the heart fails to distribute | | | | The abnormal noise is often caused by a leaking heart |
| enough blood to meet the body's requirements, and | | | | valve, but there are many different types of murmur, |
| the horse develops heart failure as a result. | | | | with a range of underlying causes. |
| Signs of heart failure include: | | | | Functional, or flow, murmurs are not associated with a |
| - Exercise intolerance | | | | heart problem. These are completely normal and are |
| - Weight loss | | | | commonly heard in fit animals, such as racehorses. |
| - Coughing | | | | They are attributed to the large volume of blood |
| - Rapid breathing | | | | moving through the heart that causes audible vibrations |
| - Ventral oedema (a pooling of fluid that is seen as a | | | | similar to water rushing through pipes. |
| swelling on the underside of the horse's abdomen). | | | | Temporary heart murmurs can happen with any |
| A horse in heart failure will have a high resting heart | | | | condition that causes an elevation in heart rate. This is |
| rate, usually more than 50 beats per minute in order to | | | | sometimes found in horses suffering from colic or |
| compensate for the reduced volume of blood being | | | | other painful conditions, a murmur is detected while the |
| pumped with each contraction. | | | | horse is distressed and its heart rate is elevated, but |
| Sometimes these signs only become apparent when | | | | this later disappears. A common type of murmur |
| extra demands are placed upon the horse, such as a | | | | occurs as a sult of vibrations as blood leaks back |
| higher level of exercise, or when a mare is put in foal. It | | | | through a valve in the wrong direction. |