Pulmonic Regurgitation in Horses: What This Heart Murmur Means

Quick Answer
  • Pulmonic regurgitation means blood leaks backward through the pulmonic valve after the heart pumps.
  • In horses, this finding is uncommon and may be mild, incidental, or linked to another heart problem such as valve change, pulmonary hypertension, or rarely infection.
  • Many horses have no obvious signs at first. Poor performance, exercise intolerance, fast breathing, fainting, or swelling are more concerning findings.
  • A murmur alone does not tell you how serious the problem is. Your vet usually needs echocardiography with Doppler to confirm the valve involved and estimate severity.
  • Management often focuses on monitoring and treating the underlying cause rather than the valve leak itself.
Estimated cost: $350–$2,500

What Is Pulmonic Regurgitation in Horses?

Pulmonic regurgitation, also called pulmonic insufficiency, happens when the pulmonic valve does not close tightly and some blood flows backward from the pulmonary artery into the right ventricle. Your vet may first suspect it after hearing a murmur, but the murmur itself cannot confirm which valve is leaking or how important the leak is.

In horses, clinically important valve disease is more often discussed with the aortic, mitral, or tricuspid valves. Pulmonic valve disease is considered uncommon, and severe primary pulmonic valve problems are rare. That means a horse with suspected pulmonic regurgitation often needs a careful workup to decide whether this is a mild incidental finding or part of a bigger heart or lung circulation problem.

Some horses with mild regurgitation continue normal turnout and light work with monitoring. Others may have reduced athletic ability, rhythm changes, or signs of heart strain if the leak is more significant or if another disease process is present. The practical question is not only "Is there a murmur?" but also "Is the heart adapting well, and is there an underlying cause we need to address?"

Symptoms of Pulmonic Regurgitation in Horses

  • No visible symptoms, especially with mild or incidental regurgitation
  • Heart murmur heard during a routine exam or pre-purchase exam
  • Reduced stamina or poor performance during work
  • Exercise intolerance or taking longer to recover after exercise
  • Fast breathing or increased effort with exercise
  • Irregular heartbeat or intermittent rhythm abnormalities
  • Weakness, collapse, or fainting episodes, which are more urgent
  • Jugular distension, ventral edema, or other signs of right-sided heart strain in advanced cases

Many horses with mild valve leakage act completely normal, so the first clue may be a murmur your vet hears on exam. When symptoms do appear, they often relate to reduced exercise capacity rather than obvious illness at rest.

See your vet promptly if your horse has poor performance, unusual fatigue, or an irregular heartbeat. See your vet immediately if there is collapse, labored breathing, blue or gray gums, marked swelling under the chest or belly, or distended jugular veins, because those signs can point to significant cardiovascular compromise.

What Causes Pulmonic Regurgitation in Horses?

Pulmonic regurgitation can develop when the valve leaflets are abnormal, stretched, inflamed, or unable to meet properly during closure. In some horses, the leak may be secondary to changes in blood flow or pressure in the pulmonary artery rather than a primary defect of the valve itself.

Possible causes include congenital valve abnormalities, age-related or degenerative valve change, and pulmonary hypertension. Pulmonary hypertension means increased pressure in the lung circulation, which can alter valve function and may occur secondary to other heart or lung disease. Infective endocarditis is another possible cause of valve insufficiency in horses, but pulmonic valve infection is considered exceedingly rare.

Sometimes the bigger issue is not the valve leak alone but what it represents. A horse with suspected pulmonic regurgitation may actually have another structural heart problem, an arrhythmia, or disease affecting the lungs and pulmonary vessels. That is why your vet may recommend a broader cardiac workup instead of assuming the murmur is harmless.

How Is Pulmonic Regurgitation in Horses Diagnosed?

Diagnosis starts with a full physical exam. Your vet will listen for the timing and location of the murmur, check pulse quality, assess gum color, and look for signs such as jugular distension, edema, or abnormal breathing. A murmur can suggest turbulent blood flow, but it does not reliably measure severity.

The key test is echocardiography, which is an ultrasound of the heart. Doppler echocardiography helps your vet identify backward blood flow across a valve, estimate how severe the regurgitation is, and look for chamber enlargement or pressure-related changes. Electrocardiography may also be used to look for rhythm disturbances, especially in horses with poor performance or intermittent collapse.

Depending on the case, your vet may also recommend bloodwork, thoracic imaging, exercise evaluation, or referral to an equine cardiology service. This stepwise approach helps separate a mild incidental murmur from disease that could affect safety, athletic use, breeding plans, or long-term comfort.

Treatment Options for Pulmonic Regurgitation in Horses

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$350–$900
Best for: Horses with an incidental murmur, no collapse, no breathing distress, and no obvious decline in performance, especially when pet parents need a stepwise plan.
  • Farm call or clinic exam with cardiac auscultation
  • Rest and exercise modification while monitoring symptoms
  • Baseline bloodwork if another illness is suspected
  • Referral discussion and watchful follow-up if the horse is stable
  • Repeat exam in weeks to months depending on workload and findings
Expected outcome: Often fair to good if the murmur is mild and no significant structural disease is found, but prognosis remains uncertain until imaging confirms the cause.
Consider: Lower upfront cost, but it may miss the exact valve involved or underestimate severity. This tier is less helpful for performance horses or horses with concerning signs.
Most Common

Recommended Standard Treatment

$900–$1,800
Best for: Most horses with a newly detected murmur, reduced performance, uncertain athletic expectations, or any concern that the murmur may reflect meaningful heart disease.
  • Complete veterinary exam and murmur grading
  • Echocardiography with Doppler to confirm pulmonic regurgitation
  • Electrocardiogram if rhythm abnormalities are suspected
  • Targeted bloodwork and blood pressure or oxygenation assessment as indicated
  • Written exercise recommendations and recheck plan
Expected outcome: Variable. Horses with mild regurgitation and no chamber enlargement may do well with monitoring, while horses with secondary pulmonary hypertension, arrhythmias, or progressive heart change have a more guarded outlook.
Consider: This tier gives the clearest practical information for decision-making, but it requires specialty-level imaging in many regions and may still not identify a reversible cause.

Advanced / Critical Care

$1,800–$2,500
Best for: Performance horses, breeding animals, horses with collapse or arrhythmias, and horses with suspected complex heart disease or pulmonary vascular disease.
  • Referral to an equine cardiology or internal medicine service
  • Comprehensive echocardiography and advanced rhythm evaluation
  • Exercise testing or post-exercise ECG when poor performance is the main complaint
  • Thoracic imaging and expanded diagnostics for suspected pulmonary hypertension or systemic disease
  • Hospital-based monitoring and treatment of the underlying cause when clinically indicated
Expected outcome: Depends heavily on the underlying diagnosis. Mild isolated leaks may be manageable, while severe valve dysfunction, pulmonary hypertension, or heart failure carries a guarded to poor prognosis.
Consider: Most complete information and monitoring, but higher cost range, travel to a referral center, and more testing than every horse needs.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Pulmonic Regurgitation in Horses

Bring these questions to your vet appointment to get the most out of your visit.

  1. Where is the murmur heard best, and does it sound mild, moderate, or severe?
  2. Do you think this is truly pulmonic regurgitation, or could another valve be involved?
  3. Does my horse need an echocardiogram now, or is monitoring first reasonable?
  4. Are there signs of chamber enlargement, pulmonary hypertension, or heart failure?
  5. Is it safe for my horse to keep working, competing, breeding, or traveling?
  6. Should we screen for arrhythmias with an ECG or exercise-based testing?
  7. What symptoms at home would mean I should call right away?
  8. What is the expected cost range for the next step, including referral if needed?

How to Prevent Pulmonic Regurgitation in Horses

Not every case can be prevented, especially if the problem is congenital or related to age-associated valve change. Still, regular wellness exams matter because your vet may detect a new murmur before your horse shows outward symptoms. Early recognition gives you more options for safe exercise planning and follow-up.

Good preventive care also means reducing the chance of secondary problems that can stress the heart. Keep vaccinations, dental care, parasite control, and routine medical care current, and address fever, weight loss, chronic respiratory disease, or poor performance promptly. If your horse has a known murmur, avoid making major workload changes without checking in with your vet first.

For horses used in sport, breeding, or sale, a documented cardiac baseline can be helpful. Prevention is less about stopping every valve leak from happening and more about catching meaningful disease early, monitoring trends, and tailoring care to your horse's job, age, and overall health.

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