It can be frightening to watch your dog go through a syncope or a seizure. These events can appear very similar. Seizures and their causes were discussed here. The causes and treatments of syncope are very different.
They may also urinate, defecate, or convulse.
The seizure is not usually preceded by excitement, exercise, or agitation. Instead, there may be a pre-ictal stage, which is also called an aura. During a tonic clonic, the dog’s jaws may clench, then relax, and foam at the lips. They may defecate and urinate involuntarily. This phase is characterized by confusion or disorientation, and may include restlessness or extreme sleepiness (slow recovery).
A dog experiencing syncope or seizures should be examined by their veterinarian immediately. You can tell if your dog has syncope or seizures by taking a video with your smartphone. Share it with the veterinarian.
Syncope: What causes it?
Syncope is most commonly caused by a sudden, temporary interruption in blood flow to brain. The heart’s structural and electrical problems can both cause a sudden decrease in the amount blood that reaches the brain.
Syncope occurs more often in older dogs than in younger dogs because the causes of syncope increase with age.
The heart is unable to contract properly and pump blood through the body. Congenital problems, like heart valve defects in the pulmonic and aortic valvures, can cause these problems. Certain structural abnormalities, such as dilated Cardiomyopathy and arrhythmogenic Right Ventricular Cardiomyopathy (ARVC), are not present from birth but more likely to occur in certain dog breeds. Doberman Pinschers and Boxers are the most commonly affected by genetically inherited dilated Cardiomyopathy. ARVC can affect both Boxers and Bulldogs.
Heartworm disease, mitral or tricuspid disease, and pulmonary hypertension can all cause structural cardiac abnormalities. Syncope can be caused by a condition called pericardial effusion, which is an accumulation of liquid between the outside and inside of the sac surrounding the heart.
Electrical abnormalities in the heart affect the flow of electrical impulses. These originate from a cluster in the right atria, and then travel to the ventricles and atria. The heart could not contract completely with every beat if it didn’t receive the proper electrical impulses. Arrhythmia is the name for this condition. Arrhythmias may temporarily impair blood flow to your brain.
Syncope: Diagnosing its cause
If your vet suspects a heart problem is the cause of your dog’s syncope episodes, she will order diagnostic tests to examine your dog’s heart structure and electric function. This may include chest x-rays, an electrocardiogram and an ultrasound of the heart.
A veterinarian may not see some arrhythmias on an ECG. Your dog’s vet may order a Holter Monitor if she suspects your dog is suffering from an intermittent arrhythmia. This device records your dog’s electrical activity over a 24 hour period.
Holter monitors for dogs are similar to Holter monitors for humans. The chest of your dog is shaved, and ECG patches applied. Wires connect the ECG patches to the Holter monitor. The ECG patches will be covered and protected by a special shirt. The shirt has a pouch with velcro that holds the Holter monitor. It is about the size of a deck playing cards.
You will need to keep a record of the activities your dog performed during the 24 hours he wore the recording device. The Holter monitor, along with your dog’s log of activities over the 24 hours that the recording device was worn by him, is then sent to a veterinarian cardiologist for analysis.
When there is an abnormality in your dog’s heart, you can take several medications to help it work better. It is important to find the right diagnosis in order to prescribe the appropriate medication.
Syncope can be caused by other causes
Syncope can be caused by low blood sugar, severe dehydration, or acute blood loss. Syncope can be caused by hypoxemia (low oxygen levels in the blood), which is often caused by severe lung diseases, anemia that has suddenly developed, or congenital heart defects called shunts. Untreated, these conditions can lead to seizures.
A condition known as neurocardiogenic syncope, also called vasovagal synchronicity in dogs, exists. As of this writing, the condition is not fully understood. This condition causes dogs to have syncopal episodes after a bout with coughing, vomiting or gagging. It can also occur during periods of excitement or exercise. According to current theories, pre-syncopal activities cause a sudden drop in blood pressure and heart rate. This causes an interruption in blood flow to brain. Holter monitors may be required to diagnose neurocardiogenic syncope, as with certain arrhythmias.
Syncope can be caused by many things. Once the underlying causes are properly identified and treated, the frequency of syncopal events can be reduced.
SyncopeSeizureCollapsing onto their side
The neck and back arches
Paddling with the legs
Involuntary urination and defecation
The mouth is frothing
Jaw clenching is a rapid clenching-and-unclenching.
Disorientation following an event
Exercise, excitement or gagging immediately before the event
Whole Dog Journal: Syncope in Dogs