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5 Common Cardiovascular Conditions in Canine Athletes

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Overview

All dogs love to play, but some dogs excel at it! Canine athletes lead vigorous and exciting lives, whether competing in agility, dock jumping or disc contests, or spending their time herding and entering field trails. These athletics pups can also be found assisting police, military or emergency personnel.

Being an athlete comes with a lot of work, and just like in humans, a dog’s body can be affected by engaging in strenuous training, work and play. Human and dog athletes alike undergo cardiac remodeling wherein the heart’s structure can change over time to accommodate the new needs of the body. While this is a normal process, sometimes the remodeling can cause a problem, such as when an area of the heart muscle thickens, which can in turn cause ventricle narrowing and restrict blood flow.

While exercise does keep a body healthy, too much can be harmful. Supplements and a healthy diet can support an active body, but always consult your veterinarian when making any changes or adding new elements to your dog’s regimen. 


Left ventricle hypertrophy

LVH occurs when the left ventricle wall of the heart thickens in response to the heart needing to work harder than usual, which in turn decreases blood flow through that chamber. This condition can affect athletes due to their consistent training and exercise routines that requires the heart beat faster and harder to keep pumping blood to where the body needs it.

Symptoms

While LVH is a condition, it can also be a symptom of, or caused by, other heart conditions, and may be accompanied by other signs that can help point to a cause or indicate heart disease. LVH can also be a predictor of sudden cardiac death.

  • Shortness of breath
  • Dizziness
  • Fainting
  • Fatigue
  • Rapid heartbeat
  • Chest pain

Causes

Diagnosis

Be sure to relate any and all symptoms you’ve noticed in your dog to your veterinarian, along with your dog’s activity level, and how long they’ve been engaged in vigorous exercise. After a physical exam that will include listening to your dog’s heart and lungs, your veterinarian may order several tests to help with the diagnosis.

Many times, LVH is first seen on an ECG. Imaging tests including X-rays, ultrasounds and an echocardiogram are used to look that any thickening or other abnormalities of the heart. Blood tests can alert to high levels of certain proteins that can signal heart failure, while a urinalysis can provide further insight.

Treatment

For a left ventricle hypertrophy that is attributed to an athletic lifestyle, often no treatment is required, but you may need to stop exercising your dog for several months.

Medications may be given for several different reasons, such as ACE inhibitors to control blood pressure, diuretics to reduce fluid retention, vasodilators to widen the arteries and veins, digitalis glycosides or pimobendane.

Average cost of treatment: $500 - $6,000.


Hypertrophic cardiomyopathy

This rare cardiac disease is characterized by the thickening of one or more areas of the heart. In HCM, generally the lower chambers, or ventricles, are affected, and the condition may be a cause or result of left ventricle hypertrophy. The septum, or the wall that separates the right and left ventricles in the heart, can also be thickened, reducing blood flow from the left ventricle. In athletes, HCM is directly caused by strenuous and continuous exercise.

HCM can lead to other heart conditions, including arrhythmias, aortic thromboembolism, blood clots, and decreased blood flow. This heart condition can also cause muscle cells to die which may scar and lead to fibrosis.

Symptoms

Hypertrophic cardiomyopathy can be quiet and show no symptoms, but dogs that are affected often have signs.

  • Coughing
  • Exercise intolerance
  • Rapid breathing
  • Fainting
  • Collapse
  • Heart murmurs

Causes

  • Repetitive, strenuous exercise
  • Left ventricle hypertrophy
  • Genetics
  • High blood pressure
  • Hyperthyroidism
  • Cancer
  • Amyloidosis
  • Inflammation

Diagnosis

After a physical exam, if your veterinarian suspects HCM or another health issue, they will order imaging tests. These can include an echocardiogram, X-rays and ultrasounds to look at heart function and thickened areas. An ECG is also ordered to look at the heart beat. Blood testing, a blood pressure assessment, and even a urinalysis and thyroid testing can be done. In some cases, a BNP test is recommended that looks for proteins in the blood that may indicate heart failure.

Treatment

There is no general treatment for HCM, and no medication has been proven to slow or stop the progression of the condition. Dogs with this condition are at risk of congestive heart failure and sudden death.

Medications may be given to treat some of the symptoms, or complications associated with HCM. These can include diuretics to decrease fluid in the body, ACE inhibitors to lower blood pressure, and drugs to prevent blood clots, increase heart contractability, and block calcium channels. Digitalis glycosides and pimobendan may also be prescribed.

Monitoring your dog and re-testing every 3 to 4 months allows you and your veterinarian to watch the disease’s progress and treat new symptoms that may develop.

Average cost of treatment: $500 - $6,000.


Arrhythmia

An arrhythmia is an irregular heartbeat due to abnormal electrical activity in the heart muscle. Normally, a regular heartbeat increases during activity and decreases during rest at a normal and predictable pace. While this is the same in dogs as in humans, a dog’s heartbeat does beat faster than ours, so discovering an irregular heartbeat can be difficult.

Dogs who exercise or train regularly can sometimes experience an irregular heartbeat due to the excessive activity. Canine athletes are particularly susceptible to bradycardia, or an irregularly slow heartbeat. For dogs, this would be a heart that beats 40 times or less per minute.

Symptoms

  • Abnormally fast heartbeat
  • Abnormally slow heartbeat
  • Moving slow
  • Difficulty breathing
  • Fatigue
  • Weakness
  • Collapsing
  • Coughing
  • Dizziness
  • Decreased ability to exercise
  • Seizures
  • Loss of consciousness

Causes

There are several kinds of arrhythmias that can affect dogs, and each can be caused by various conditions. 

Diagnosis

A lot goes into diagnosing an irregular heartbeat, as there are many conditions that could cause it. First, your veterinarian will conduct a thorough physical exam, and listen to the heart for the heartbeat. Relate all symptoms you have noticed, including changes in heartbeat during different activities, and changes in appetite, activity levels and mood in your dog.

Usually, your vet will do several kinds of tests to help narrow down a cause, including a full blood panel, a urinalysis, and testing for electrolyte balance. Then, X-rays and ultrasounds of the chest will be taken to look for an enlarged heart or other abnormalities, an echocardiogram performed, and an ECG to more closely listen to the heart rate and discover is there are any premature contractions. In some cases, an atropine response test will be performed.

If the irregular heartbeat is not present during the vet visit, you may be sent home with a Holter monitor that records your dog’s heartbeat for 24 hours for the vet to review.

Treatment

Treatment of an irregular heartbeat will depend on whether the beat is too fast or too slow, and the underlying reason for the abnormality. Drug overdoses are treated as emergencies in the hospital, and management after recovery will generally dictate that the drug will no longer be used.

Several medications can be prescribed to increase or lower the heartrate artificially, including cardiac glycosides such as Dioxin, calcium-channel blockers such as Diltiazem, anticholinergics in the case of bradycardia such as Atropine or Propantheline, antiarrhythmics such as Mexiletine or Sotalol, or xanthines such as Theophylline. 

Any breathing difficulties will be considered emergencies and treated with oxygen and IV fluids. Often, heart monitoring will continue after treatment to see if treatment is working.

Average cost of treatment: $300 - $6,500.

 

Systolic heart murmur

heart murmur is an abnormal sound from the heart produced by the turbulent flow of blood through it. In athletes, murmurs can be produced due to the increased blood flow that strenuous activity requires. A systolic murmur is heard when the blood rushes into a chamber, while a diastole murmur sounds as the blood rushes out.

Symptoms

Often, only a veterinarian will discover a heart murmur during a routine exam, as they are usually only heard through a stethoscope.

  • Heart murmurs
  • Vibration in chest accompanying heart murmur

Causes

  • Increased blood flow through heart due to strenuous activity
  • Heart abnormality, including thickening
  • Narrowing of arteries
  • Valve defect

Diagnosis

During a routine exam, your veterinarian may discover a heart murmur while listening to your dog’s heart through a stethoscope. Your vet will listen closely to determine if it is a systolic or diastolic murmur, how often it occurs and whether or not the sound increases or decreases in intensity from the start of the murmur. The murmur is then graded from very quiet to loud enough that it is accompanied with a vibration felt on the chest, Grades I through VI.

Next, MRIs, X-rays, CT scans and ultrasounds can be used to see what is happening with the heart and help diagnose the cause that led to the murmur.  Often, a heart murmur is an indication of an underlying heart condition.

Treatment

Treatment of heart murmurs depend on the underlying condition causing the murmur. In some cases, treatment is not necessary, but monitoring will likely continue. Surgery to correct a valve defect may be recommended.

Medications may be given for different conditions relating to cardiac thickening or enlarging, such as ACE inhibitors to control blood pressure, diuretics to reduce fluid retention, or digitalis glycosides or pimobendane. For constricted or narrowed arteries, vasodilators to widen the arteries and veins may be given.

Average cost of treatment: $1,800 - $5,000.


Athletic heart syndrome

Athletic heart syndrome is the combination of symptoms that have developed through the rigorous training and exercise routines of athletes, both human and canine. This condition is common to endurance athletes, and has been documented in working sled dogs.

Symptoms

The signs of athletic heart syndrome are those of the conditions it includes, i.e., left and right ventricular hypertrophy, bradycardia, sinus arrhythmia, and heart murmurs and gallops.

  • Difficulty breathing
  • Dizziness
  • Fainting
  • Lethargy
  • Moving slow
  • Rapid or slow heartbeat
  • Weakness
  • Inability to exercise
  • Collapse
  • Seizures
  • Chest pain
  • Heart murmurs
  • Vibration in chest accompanying heart murmur

Causes

  • Continuous, vigorous exercise
  • Cardiac remodeling
  • Genetics

Diagnosis

Since this condition affects athletes specifically, be sure to tell your vet about your dog’s activity, training and any work or competitions, including how long and how often they’ve been doing it, and how the symptoms have progressed.

To diagnose athletic heart syndrome, your veterinarian will start by performing a physical exam and listen to the heart. The presence of murmurs and an irregular heartbeat will immediately alert them to a problem. This is usually followed up by an ECG, and various imaging tests to visually see any heart thickening, including X-rays, CT scans, MRIs and ultrasounds. An echocardiogram is performed, and various blood panels are generally run. A urinalysis and other testing may occur to rule other conditions out.

Once your veterinarian has the main components that make up athletic heart syndrome, namely, ventricular hypertrophy, bradycardia, sinus arrhythmia, and heart murmurs, along with a history of vigorous activity, this condition can be diagnosed.

Treatment

Depending on your dog’s particular condition, your vet may recommend halting activity for several months to allow the body to readjust and reduce the factors that created athletic heart syndrome. If allowed to continued unchecked, this condition can lead to sudden cardiac failure.

Other treatments center on treating each symptom, such as medications for regulating blood pressure, reducing fluid retention, and helping the heart beat and function properly. Monitoring should continue with results dictating further treatments as necessary.

Average cost of treatment: $500 - $6,500.

Cardiovascular conditions can be expensive to treat. If you suspect your dog is at risk of heart complications, start searching for pet insurance today. Wag!’s pet insurance comparison tool lets you compare plans from leading companies like PetPlan and Embrace. Find the “pawfect” plan for your pet in just a few clicks!

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© 2022 Wag Labs, Inc. All rights reserved.