Researcher: Dehydration Can Lead to Misdiagnosis of Heart Disease

Changes in a horse's heart size due to dehydration might lead to a misdiagnosis of heart disease based on echocardiogram, according to researchers at the University of Pennsylvania's New Bolton Center who recently completed a study on the subject. They also uncovered another potential use for echocardiograms in the process.

"The size of the heart changes in other species when they are dehydrated, so we wanted to see whether similar changes occurred in horses," said Claire Underwood, MA, VetMB, MRCVS, a fellow in ultrasonography in Penn's department of clinical sciences , in Kennett Square, Pa. "Heart size is used to help evaluate cardiac disease. So when a (dehydrated) horse comes in for cardiac evaluation, it is possible to misjudge (the severity of the heart condition) because of the dehydration."

Underwood and her colleagues set out to examine what changes dehydration can cause in horses' hearts so they could provide veterinarians accurate information to consider when performing equine echocardiograms. The team found the most significant reductions in size happened in the left ventricle (the chamber of the heart that pumps oxygenated blood throughout the body) and the left atrium (which transports the oxygenated blood from the pulmonary veins into the left ventricle) of dehydrated horses. The thickness of some wall structures within the heart also increased.

Additionally, since Underwood and her team confirmed that dehydration leads to a visibly altered heart size on an echocardiogram, they suggested that echocardiography might prove to be a "noninvasive method of monitoring volume status and response to fluid therapy in hypovolemic horses."

Hypovolemia is a condition that results in abnormally low levels of blood plasma in the body, such that the body is unable to properly maintain blood pressure, cardiac output of blood, and normal amounts of fluid in the tissues.

Underwood reminds horse owners that it is always important that horses have free access to plenty of good quality water, and water should not be withheld for long periods.

The study, "Echocardiographic changes in heart size in hypohydrated horses," was published in October online ahead of print in The Journal of Veterinary Internal Medicine. The abstract is available on PubMed.

About the Author

Marie Rosenthal, MS

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