Dr Randhir Singh
The heart is essential to the body, regardless of the species. Luckily, when dogs have heart problems, veterinary cardiologists are able to keep things ticking along. Pacemakers have been used in human medicine since the early 1960s but, first veterinary pacemaker implantation was carried out in a dog during late 1980s. Today, in dogs, pacemakers are used both as a life-saving intervention and to improve quality of life.
How pacemakers work?
A pacemaker is made up of two parts. “A generator, a lithium battery, and a computer chip that a veterinary cardiologist can programme to your dog’s requirements make up one component. The other component comprises of wires, known as leads, that are linked to the interior of the heart and run from the generator through veins in the neck. When the dog’s heart rate drops below the permitted range established by the vet, often between 80 and 120 beats per minute, the pacemaker is triggered. When the pacemaker activates, it causes the heart to contract more forcefully until the rhythm of the heart is restored and it can continue on its own.
Why would your dog need a pacemaker?
If there are any clinical indications or symptoms and your pet’s heart rate is too slow. The most typical symptoms of a slow heart rate include episodes of collapsing and fainting, an inability to exercise, quick or fast breathing, and pale gums. Older canines are more likely to need pacemakers. Quite frequently, the symptoms suggest ageing when, in reality, they are brought on by a slow heartbeat.
The first step is to document your pet’s heart rhythm. Heart rhythm can be determined from a heart rhythm strip, termed an ECG/EKG, or the placement of a 24-hour Holter which records your dog’s heart rate and rhythm over a 24-hour time period. Additional diagnostics to determine if your pet is a good candidate for pacemaker implantation are: full blood work, urine analysis, blood pressure, Chest (and possibly abdominal) X-rays, echocardiogram (ultrasound using sound waves) and abdominal ultrasound. The reason for the tests is that most dogs are geriatric, or elderly, by the time they develop these slow heart rhythms. A veterinary cardiologist will ensure that no other diseases or complications are present before proceeding with pacemaker implantation.
How is a pacemaker implanted?
Pacemakers are implanted while the dog is under anesthesia. The procedure is most commonly done using minimally invasive techniques. The equipment used is the same that’s used in humans. Typically, the pacemaker is inserted through a small incision in the patient’s neck that allows us access to the jugular vein. Once it is confirmed with continuous X-ray (C-arm/ fluoroscopy)/ Cath-lab that the pacemaker lead is properly placed in the right ventricle (or chamber) of the heart, we attach it to the generator and program the pacemaker to meet your dog’s specific needs. If your dog has skin disease or any other disease that prevents placement in the neck, the pacemaker can and may be placed in the abdomen, or stomach. This is known as an epicardial pacemaker. Cats always require placement of pacemakers in their abdomen, as their blood vessels are too small to place a lead directly inside their heart.
Expectations during and after the procedure
The procedure itself usually will take 1-2 hours to complete. Veterinary cardiologist will take chest X-rays after the procedure to ensure the pacemaker lead is in an ideal position. After the procedure, your pet will need to stay overnight for continuous heart rate monitoring to ensure their pacemaker is functioning correctly. Most dogs go home the day after their procedure. It is important to keep the incision clean and dry. A bandage will be placed over the incision for the first 7-10 days to reduce swelling. Activity should be restricted for 4-6 weeks after surgery to minimize the chance the pacemaker lead gets dislodged. Your dog will need a harness instead of a collar to reduce and prevent pulling on the pacemaker lead in their neck. Thankfully, the majority of pacemaker patients do not require any lifelong cardiac medications post-procedure.
Re-checks to evaluate pacemaker function and battery life will need to be performed 4-6 weeks following pacemaker placement, and then every 6 months after this.
Is there anything your dog should avoid after pacemaker implantation?
If your dog has a pacemaker and requires a Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) scan, notify your veterinarian. Venepuncture (process of drawing blood from veins) of the right jugular vein should be avoided, as this could damage the pacemaker lead. Microwaves do not present a danger to your dog’s pacemaker. If your dog passes away or is humanely euthanized, the pacemaker will not keep their heart beating or artificially alive.
(The author is a veterinary dialysis specialist)
Dr Randhir Singh