Syncope in dogs, or fainting, can be a frightening experience for both dog owners and dogs alike. In this blog post, we'll take a closer look at what causes syncope in dogs, as well as some of the most common treatment options. We'll also provide some tips for preventing syncope in your furry friend. So whether your dog has already fainted or you're just looking to learn more about this condition, read on to learn more about syncope in dogs.
What is syncope in dogs?
Syncope is a condition in which the brain suddenly does not receive enough blood flow and consequently loses consciousness. In dogs, a lack of cerebral blood flow for more than 5-6 seconds can cause syncope. Syncope can be caused by a number of different factors, including heart arrhythmias, heart failure, pulmonary hypertension, vasovagal syncope, and tussive syncope.
What are the signs of syncope in dogs?
The most common sign of syncope in dogs is the sudden loss of consciousness. This can be accompanied by a loss of muscle tone (known as atonia), opisthotonos (a condition in which the head and neck are extended and the back is arched), and urination. In most cases, syncope only lasts for a few seconds to a minute or two. However, if your dog experiences a prolonged syncopal episode, it is important to seek veterinary care immediately.
Syncope is commonly brought on by coughing, barking, excitement, exercise, or pulling on a leash for example. Afterward, the dog is typically alert and aware.
What are the causes of syncope in dogs?
There are a number of different conditions that can lead to syncope in dogs. We will discuss some of the most common causes below.
Arrhythmias
Arrhythmias, or abnormal heart rhythms, are one of the most common syncopal triggers in dogs. If the heart is beating too rapidly and irregularly, it doesn't have time to fill properly and this results in a decrease in blood flow to the brain. If the heart is beating too slowly, blood flow to the brain is reduced as well because not enough blood is being pumped.
If your veterinarian suspects that your dog has an arrhythmia, they will recommend performing a detailed cardiac examination and may also recommend additional tests such as an electrocardiogram (EKG), Holter monitor, or echocardiogram.
The treatment for arrhythmias will depend on the underlying cause of the arrhythmia. Anti-arrhythmia medications will be used to control the heart rate if the arrhythmia is caused by an underlying heart condition. If the arrhythmia is secondary to a metabolic imbalance, such as electrolyte abnormalities, treatment will focus on correcting the imbalance.
Heart failure
Heart failure is another common cause of syncope in dogs. Heart failure occurs when the heart is unable to pump enough blood to meet the body's needs. They may also experience other signs such as exercise intolerance, coughing, difficulty breathing, and a decrease in appetite. Heart failure can be caused by a number of different conditions, including cardiomyopathies, mitral valve disease, and congenital heart defects.
If your veterinarian suspects that your dog has heart failure, they will likely recommend performing some or all of the following tests: a complete blood count, biochemical blood profile, chest radiographs, electrocardiogram (EKG), and echocardiogram.
The treatment for heart failure will focus on managing the underlying cause of the condition and supporting the heart with medications. Diuretics may be prescribed to remove excess fluid from the body and help relieve congestion. Other medications may be used to improve heart function, such as ACE inhibitors, beta-blockers, and medications designed to increase cardiac contractility.
Pulmonary hypertension
Pulmonary hypertension is a condition in which the pressure in the pulmonary arteries (the arteries that carry blood from the heart to the lungs) is too high. This can lead to syncope because it decreases blood flow to the brain. Dogs with pulmonary hypertension may also experience other signs such as exercise intolerance, coughing, and difficulty breathing.
If your veterinarian suspects that your dog has pulmonary hypertension, they will likely recommend performing some or all of the following tests: a complete blood count, biochemical blood profile, chest radiographs, electrocardiogram (EKG), echocardiogram, and right heart catheterization.
The treatment for pulmonary hypertension will focus on managing the underlying cause of the condition and supporting the heart with medications. Medications that may be used include diuretics, ACE inhibitors, and vasodilators.
Vasovagal syncope
Vasovagal syncope is a type of syncope that is brought on by a sudden drop in blood pressure. Vasovagal syncope is caused by an increase in parasympathetic tone and a decrease in sympathetic tone, which leads to low blood pressure and a slow heart rate. The parasympathetic system is responsible for resting and digesting, while the sympathetic system is responsible for the "fight or flight" response.
Causes of vasovagal syncope include fear, pain, brachycephalic airway syndrome, strenuous exercise, and standing for long periods of time. Dogs with vasovagal syncope may also experience other signs such as bradycardia (slow heart rate), hypotension (low blood pressure), and ataxia (uncoordinated movement).
While there is no definitive test for vasovagal syncope, if your veterinarian suspects that your dog has vasovagal syncope, they may recommend performing some or all of the following tests: a complete blood count, biochemical blood profile, chest radiographs, electrocardiogram (EKG), and echocardiogram.
The treatment for vasovagal syncope will focus on managing the underlying cause of the condition. If the syncope is caused by fear or pain, measures should be taken to address those issues. If the syncope is caused by strenuous exercise, the dog should be restricted from that activity. If the syncope is caused by standing for long periods of time, the dog should be given a place to lie down.
Tussive syncope
Tussive syncope is a type of syncope that is caused by coughing. Tussive syncope is most commonly seen in dogs with tracheal collapse, laryngeal paralysis, and bronchial disease.
Dogs with tussive syncope may also experience other signs such as coughing, difficulty breathing, and exercise intolerance. If your veterinarian suspects that your dog has tussive syncope, they will likely recommend performing some or all of the following tests: a complete blood count, biochemical blood profile, chest radiographs, and an electrocardiogram (EKG).
The treatment for tussive syncope will focus on managing the underlying condition. If the syncope is caused by tracheal collapse, laryngeal paralysis, or bronchial disease, the dog will need to be treated for those conditions.
Commonly asked questions from dog owners about syncope
Is syncope in dogs serious?
The syncopal event itself is not serious but the underlying cause of the syncope may be. It is important to consult with your veterinarian to determine the cause of syncope and to develop a treatment plan.
What triggers syncope in dogs?
There are many possible triggers for syncope in dogs, including arrhythmias, heart failure, pulmonary hypertension, vasovagal syncope, and tussive syncope.
How is syncope in dogs diagnosed?
Syncope in dogs can be diagnosed with a variety of tests, including a complete blood count, biochemical blood profile, chest radiographs, electrocardiogram (EKG), echocardiogram, and right heart catheterization.
What is the treatment for syncope in dogs?
The treatment for syncope in dogs will vary depending on the underlying cause of the condition. Treatment focuses on treating the underlying condition that causes syncope, rather than the event itself.
How long does syncope last?
An episode of syncope lasts for approximately 20-30 seconds. As a pet parent, this short period of time can feel like an eternity! Dogs will likely recover within a few minutes of the syncopal episode.
Syncope in dogs is a condition in which the brain does not receive enough blood flow and consequently loses consciousness. Syncope can be caused by arrhythmias, heart failure, pulmonary hypertension, vasovagal syncope, and tussive syncope. The treatment for syncope will focus on managing the underlying condition. If you think your dog may be experiencing syncope, please speak with your veterinarian.