What are pacemakers?

A pacemaker is a device that, through surgical intervention, is integrated into the dog's heart to help it maintain a beating frequency appropriate to its needs. It consists of a pulse generator (battery), an electrode that connects it to the heart's myocardium, and programming equipment.

Its use is better known in humans, but as we indicated, pacemakers can also be placed in dogs whose heart beats too slowly. This condition is known as bradycardia and carries a high risk of death, as we will explain below. The device will ensure that the heart does not slow down or stop again, thus extending both the quality and the life expectancy of your dog.

Bradycardia and Diseases that Require Pacemakers for Dogs

To understand bradycardia, we can start with the fact that the dog's heart is equipped with its own natural pacemaker called the sinus node. Its function is basically what we explained for the pacemaker: to create electrical impulses transmitted to the heart to produce the much-needed beats.

In some cases, the beats can slow down, leading to a low heart rate, or even stopping altogether. This can indicate failures in the natural pacemaker or the electrical impulse transmission to the rest of the heart, for example, in some part of the "wiring." Each of these cases that require pacemakers for dogs has a name: sinus node disease or sick sinus syndrome and heart block, respectively.

Sick Sinus Syndrome (SSS)

SSS occurs when the natural pacemaker, the sinus node, malfunctions, causing the dog's heartbeat to become irregular. These can be both fast and very slow. They usually occur in West Highland White Terriers, Dachshunds, Boxers, Cocker Spaniels, Miniature Schnauzers, and Standard Schnauzers.

Atrial Block

This condition is much rarer than SSS. An atrial block consists of the absence of electrical and mechanical activity in the atria, the two upper chambers that receive the blood that enters the dog's heart. A more severe form known as advanced atrioventricular block may also develop.

Signs Your Dog May Need a Pacemaker

With so many technical terms, caregivers are probably still at a loss about whether their dog may need a pacemaker. For clarity, it's worth discussing symptoms that often suggest something is wrong with a dog's heart.

The symptoms that can indicate a heart problem include weakness, lethargy, fainting, shortness of breath and increased respiratory rate while at rest, exercise intolerance, and decreased appetite.

The diagnosis of sick sinus syndrome or atrial block and the need for a pacemaker will depend on recommendations from a veterinary cardiologist. After a physical evaluation of your canine patient, your vet could recommend tests to confirm or rule out the possible causes of the symptoms mentioned.

The cardiac study will include at least one electrocardiogram, accompanied by detailed blood tests. The vet may also order chest x-rays and an abdominal ultrasound if any systemic disease, such as cancer, is suspected.

It is worth noting that canine candidates for a pacemaker are those in which the bradycardia is not due to structural heart disease. Most canines weighing more than 3 kg can receive this device through a procedure known as transvenous pacemaker implantation; for those with less weight, a different procedure is used.

Risks of Dog Pacemaker Surgery

Dog pacemakers are a very effective solution to the problems mentioned above, but it is an invasive procedure, and the simple fact of requiring anesthesia increases the risks for patients.

For example, in dogs where the heart rate is very low, the effects of anesthesia can be fatal. The good news is that there are ways to reduce these scenarios, such as pacing the dog's heart before administering any of these anesthetic medications.

What is the prognosis for dogs after placing a pacemaker?

In general, the prognosis after the implantation of a pacemaker for dogs is very positive. However, it is necessary to maintain a series of care after the intervention to see results.

After the surgery, dogs usually return for follow-up every two days, and temporarily have their necks wrapped in a large bandage. The bandage’s function is essential and goes beyond protecting the device; it will prevent irritation, infection, and swelling of the incision site, as well as limit head movement.

This brings us to another crucial point - for four to five weeks, the canine's physical activity should be minimal to facilitate their wound healing. Therefore, jumping and interactions with other pets are discouraged. Collars will also be prohibited for the same reason, so using a harness is recommended instead.

Read more:

Can dogs develop heart arrhythmias?

Atrial Fibrillation in Dogs and Cats

Ventricular Tachycardia in Dogs and Cats

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