Heart check at the horse trials: How an ECG during a cross country gallop kept Cruz in the game
Jennifer Berdell had a problem most eventers would recognize: A horse she loved, a season she'd planned for, and a question she couldn't answer on her own.
Moonlight Crush, known at home as Cruz, is a 19-year-old Belgian warmblood gelding who previously competed at the four-star level in eventing, and was still working hard in the novice division under Berdell's lease. He was sharp, willing, and fit. He also had a heart murmur.
A murmur had turned up incidentally earlier in the year during a routine exam, and it was still present when Cruz received his spring vaccinations.
Woodside Equine Clinic in Ashland, Virginia, referred Cruz to the Marion duPont Scott Equine Medical Center in Leesburg, Virginia — one of three animal healthcare facilities and teaching hospitals of the Virginia-Maryland College of Veterinary Medicine — for a full cardiac evaluation.
What happened next was something Berdell hadn't anticipated: the team didn't just examine Cruz in the hospital. They followed her to the showground.
From the hospital to the stadium
Cruz arrived at the Equine Medical Center on April 15, bright and alert, and moving without lameness. His vital signs were normal; he was in great body condition, well-muscled, with a smooth coat appropriate for the season.
The cardiac examination found two murmurs: a grade 3/6 holosystolic and a grade 3/6 diastolic, both audible from either side of his chest and loudest on the left. An echocardiogram followed.
Krista Estell, clinical associate professor of equine medicine, led the evaluation with medicine resident Patrick McFadden assisting. The echocardiogram revealed moderate aortic regurgitation, which is a common age-related finding in horses, along with mild mitral and tricuspid regurgitation. Critically, Cruz showed no evidence of left ventricular volume overload. His pressure differentials were normal, consistent with mild to moderate insufficiency rather than the advanced disease that would ground a horse.
But a resting echocardiogram can only tell part of the story. In horses, many arrhythmias appear only under cardiovascular stress, the kind that comes from galloping cross country or clearing stadium fences. To know whether Cruz was truly safe to compete, Estell needed to see his heart at work.
"Dr. Estell attended my weekend show to do an ECG on Cruz while we did stadium Jumping and cross country, which was the perfect way to truly test his heart function and recovery so she could make recommendations," Berdell said.
The plan came together at Morven Park in Leesburg, Virginia; Cruz's first recognized horse trial of the year, on March 28–29. During the cross-country phase, Estell attached a non-invasive electrocardiogram monitor to record Cruz's heart rate and rhythm as Berdell piloted him through the course. It was a diagnostic tool deployed in exactly the conditions that mattered: maximum exertion during actual competition.
What the Data Showed — and What It Means
An exercise ECG captures what rest cannot: arrhythmia that surfaces only under load, the heart's recovery rate after peak exertion, and whether the electrical signals coordinating each beat remain stable when the body demands the most from them.
For a horse with known aortic regurgitation, this kind of monitoring isn't just precautionary; it's the difference between a guess and a diagnosis. While Cruz competed, Estell was able to monitor the ECG from the spectator area, ensuring a good reading even while galloping and jumping on the cross-country course.
Cruz's results gave Berdell the clarity she needed. His heart function under competition conditions supported continued work in the novice division. The age-related murmur is manageable with medication and regular monitoring rather than retirement.
"Everything turned out well, and we can manage his age-related heart murmur with medication and checkups," Berdell said.
The Equine Medical Center team recommended a follow-up echocardiogram in six months, sooner if Cruz shows any signs of exercise intolerance, unusual fatigue, limb swelling, or irregular jugular pulses. Owners and caretakers are advised to watch for any unexplained changes and contact their veterinarian or the Equine Medical Center promptly.
Aortic regurgitation can progress slowly in some horses and more rapidly in others. As it advances, regurgitant blood flow can cause the left ventricle to enlarge, reducing the heart's ability to meet tissue oxygen demands during exercise. In severe cases, that imbalance can trigger ventricular arrhythmias, which can prove dangerous for both the horse and rider. Catching it early, characterizing it carefully, and monitoring it consistently is what gives horses like Cruz the best chance of a safe, active life.
Berdell described the entire experience, from the hospital visit to the showground ECG, as educational as much as diagnostic.
"They were very kind, welcoming, and educational. They invited me to join them for Cruz's heart ultrasound and explained everything very well, so it made sense to me," she said.
Cruz is owned by Ryleigh Leavitt, who competed in Kentucky at the four-star level in 2022. Under Berdell's lease, he has continued his competition career in the novice division, and with a clearer picture of his cardiac health; that career now has a roadmap rather than a question mark.
