Fainting in Dogs

Fainting is a temporary loss of consciousness due to a lack of blood flow to the brain. What you really need to know is what caused that lack of blood flow in the first place. Generally, causes of fainting can be for many reasons that can be categorised into:

• Heart related (interruption of blood flow to the brain)
• Non-heart related (pressure on the vagus leading to a lowered heart rate)
• Certain medications (such as in a drop in blood pressure)

In most cases, a faint will not last for more than 30 seconds, and your pet should revert back to their normal self quickly afterwards. Sometimes the fainting can be triggered by coughing, showing a straining to go to the toilet, or pulling on their collar. Before a dog faints, they will sometimes show signs of sudden weakness and incoordination, crying out, a glassy-eyed look and leg rigidity.

Mainly, the cause of your dog fainting will be because of a heart related issue or a non-heart related issue, and in some cases, medication. Fainting can be more common in some breeds, like the Miniature Schnauzer, Boxers, Dobermans and Westies, simply because they are more susceptible to certain cardiac diseases that are known to cause fainting. Fainting is also seen more in older dogs, and usually only occurs in younger dogs due to a congenital heart disease.

Heart Related

This can include any condition that can lead to the heart pumping ineffectively and interrupt the blood flow to the brain. Heart diseases can often be recognized by heavy breathing, a lack of energy and coughing. Fainting is sometimes a symptom, but only in some cases. Heart related faints are usually caused by a flawed conduction system that is giving mixed signals about when the next heartbeat should be. This will lead to disturbances in the patterns of your dog’s heartbeat and lead to fainting.

Non-Heart Related

Fainting that is non-heart related will often occur when the vagus, which is a nerve, becomes overactive. The vagus is the longest nerve in the body and passes through the chest and all the way to the brain. Any pressure that is put on this nerve can cause it to react and make the heart rate slow dramatically. A dog can unintentionally trigger the vagus nerve by pulling on their collar, which will lead to a drop in the heart rate and, consequently, fainting. Coughing, straining to pass feces or any other activity that can increase the pressure in the chest and stimulate the nerve can result in fainting.

Medications

This is rare, but some prescribed medications, mostly those for circulatory issues or elevated blood pressure, can make your dog’s blood pressure drop too much and lead to fainting.

First of all, try to determine if your dog actually did faint, or if it is a seizure or another condition. They can appear to be similar, and in the heat of the moment it can be hard to tell the difference. If your dog is fainting, they will collapse to the ground without much warning, opposed to a seizure where your dog will be acting strangely before and after the event. The limbs will also be floppy in the case of a loss of consciousness, although there will sometimes be muscle twitching, but will not be rigid or moving. Dogs may lose control of their bowels or bladder while fainting. To determine the cause of your dog’s fainting, the vet will consider their history and past medications, as well as some screening blood tests used to rule out other possibilities like low blood glucose. If the cause is still not determined, an ECG will be used. 

If the fainting takes place in a regular but intermittent pattern, your vet may choose to do a 24 hour ECG monitor in order to determine the exact moment that your dog experiences an irregular heartbeat. If the cause of the fainting is due to a heart condition, they may require a pacemaker or be prescribed medication that will lower their heart rate. If it is determined that your pet had fainted due to another reason, such as difficulty passing feces, then something as simple as a fecal softener will help regulate the problem. Depending on how often your pet is fainting, tests can go on for weeks or even months.

In many cases, fainting can be prevented by avoiding certain scenarios. For example, if your dog often pulls on their collar, consider switching them to a harness to prevent them from putting pressure on the vagus nerve. Try to keep your dog away from stressful or exciting situations, as it can also increase the vagal tone caused by the vagus nerve.

Sometimes behavioral training can help keep your dog from becoming too anxious and reduce their stress levels. In order to help your veterinarian determine the cause, video footage may be helpful. If you can, try to record any information of your pet’s episode that you can and show it to your vet. Also be sure to mention to your vet if your dog is on any medication, as some can increase the chances of your dog fainting. If you are giving your companion supplements, advise the veterinarian of this also.

Treatments for fainting can have varying costs depending on the underlying cause. Depending on the required treatments it can be anywhere from $2500 to $6000, usually averaging at $2800.