senior horse hearts
When it comes to the aging equine heart, it’s not all black and white. In fact, there are many “shades of gray” when distinguishing pathological changes in the heart’s structure from simply adaptive changes in senior horse hearts.

Fortunately, a “gray-speckle tracking” ultrasound technique is helping scientists better understand, for the first time, how horses’ hearts age. By analyzing the speckling pattern of different shades of gray seen in a series of ultrasound images of the heart, they can detect functional cardiac changes in a living equine that have never before been described in science.

“Echocardiography (ultrasound technology of the heart) reveals a lot of interesting information, and different echocardiographic modes and techniques (like gray-speckle tracking) are possible and useful,” said Heidrun Gehlen, PhD, Dipl. ECEIM, professor at the Equine Clinic in Freie Universitaet, in Berlin, Germany.

In a study of 57 Warmbloods ranging in age from 3 to 30, they detected significant differences in heart structure between older and younger horses by using gray-speckle tracking during ultrasound evaluations. Mainly, the changes affected the left ventricle, reducing its capacity to contract, Gehlen said. These differences were visible starting at around age 15.

“Horses are being used for sport at older ages than they were 10 or 20 years ago,” she said, explaining the importance of such a study that describes how equine hearts evolve over time. “So veterinarians need to take into account age-related changes and diseases in horses.”

Gray-speckle tracking is a technique that analyzes the lightness and darkness of gray spots created by cardiac ultrasound imaging over a series of two-dimensional images. Already used to evaluate human heart function, it allows scientists to calculate velocities of blood pumping through the heart’s muscle, as well as measurements related to strain. Gehlen’s team’s study was the first to use gray-speckle tracking to evaluate cardiac function in horses—or any animal within the scope of veterinary medicine, she said.

Their research allowed them to describe age-related structural changes in senior horse hearts—a critical first step in recognizing pathologies (disease or damage). However, it’s too soon to understand those age-related changes’ effects on horse health, said Gehlen.

“We need much more information about what is normal in the older heart and what is perhaps pathological,” she said.

The study, “Speckle tracking analysis of myocardial deformation in correlation to age in healthy horses,” was published in the Journal of Veterinary Science.