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Sick Sinus Syndrome In Dogs

Sick Sinus Syndrome In Dogs

What Is Sick Sinus Syndrome In Dogs?

Sick sinus syndrome (SSS) is a clinical term to describe a cardiac condition of unknown cause that affects the rhythm and heart rate of dogs. The heart's electrical impulse-initiating site (called the sinoatrial node in the right atrium) fails to function normally. As a result, dogs with this condition cannot continue normal heart rates and may also go through other significant changes in heart rhythm.

The sinus node (which usually generates the heart beating) does not depolarize (fires) a trigger impulse to the heart for contraction. Consequently, the heart almost stops beating. When the heart stops contracting for > 8 seconds, then the dog will faint/collapse. Sometimes, the heart has another replacement part to commence a beat and liberate the heart from total arrest.

Generally, the sinus node has to start over again to continue its job; however, the dog’s rhythm is disturbed by many lengthy pauses. As the sinus node has a low firing rate, most dogs with SSS have more even sinus bradycardia (slow heart rate). On the other hand, some dogs with SSS will have excessive tachycardia periods (rapid rate) other than pauses.

When the dogs show symptoms of sick sinus syndrome, it is time for the implantation of a pacemaker. Pacemaker implantation for dogs with sick sinus syndrome has become a common procedure. The good news is sudden death related to SSS is rare. In the early stages of the disease, some dogs may be asymptomatic and it is detected accidentally by vets during a routine physical examination.

Symptoms Of Sick Sinus Syndrome In Dogs

  • Fainting /unconsciousness
  • Seizure
  • Weakness/Lethargy
  • Tachycardia – an irregularly fast heartbeat
  • Bradycardia – an irregularly slow heartbeat
  • Exercise intolerance
  • Labored breathing
  • Lack of appetite

Treatment Options For Sick Sinus Syndrome In Dogs

Anticholinergics - Atropine, Glycopyrrolate

Pacemaker: Sick sinus syndrome requires surgical implantation of a permanent pacemaker. This hallmark treatment is the only proven way to make sure no ongoing problems for your dog.

NSAIDs like

  • Carprofen (Aventicarp, Carprieve, Rimadyl, Canidryl, Zinecarp, Rimifin, Carpox, Vetprofen)
  • Meloxicam (Muvera, Metacam,Mobic)
  • Firocoxib (Equioxx, Previcox)
  • Deracoxib (Deramaxx, Novartis)
  • Etodolac (Lodine, EtoGesic)

Home Remedies For Sick Sinus Syndrome In Dogs

  1. Home remedies such as medications, exercise options, and diet will be based on your dog’s age and severity of the disease.
  2. Weight management is a significant concern for SSS. Several studies have shown the association between the increased risk of heart disease and being obese.
  3. Work with your vet to find the optimal dietary plan for your dog.

How To Prevent Sick Sinus Syndrome In Dogs?

  • There’s not much a pet owner can do to prevent them as Hereditary is a factor in some breeds but a high-quality diet with bone supplements may help somehow or other.
  • It is better to check the affected dogs and stop breeding affected dogs and their first-degree littermates. When you obtain a dog from an unknown lineage, do all the health checks initially.

Affected Dog Breeds Of Sick Sinus Syndrome

Miniature Schnauzer, Dachshund, Cocker Spaniel, West Highland White Terrier, Pug, Senior Dogs

Causes And Types For Sick Sinus Syndrome In Dogs

1. Causes:

  • Inherited
  • Old age

2. Types:


  • Abnormal slow heartbeat or arrhythmia
  • The typical heart rate for an adult small dog (<30 pounds) is around 120 -160 BPM beats per minute
  • This can go as low as 30 beats per minute (With sick sinus syndrome)


  • Abnormally rapid heart rate
  • Large dogs (>30 pounds) normal heart rate is 60 to 120. The heart rate of dogs can go up to 200 BPM when it is involved with physical exercise or play

3. Morbidity:

  • Cause: Inheritance
  • Gender: This is more predominant in females rather than males
  • Onset: Geriatric onset
  • Hereditable: Yes

4. Mortality:

Overall, Sick sinus syndrome is fatal and brings about life-threatening complications without proper treatment.

5. Diagnosis:

  • A complete blood count (CBC), chemistry profile
  • Abdominal ultrasound
  • X-ray
  • ECG (electrocardiograph) / echocardiogram

6. Prognosis:

The prognosis for recovery of sick sinus syndrome pacemaker surgery is excellent, with most dogs recovering completely after suitable treatment.

Symptoms completely disappear in almost 90% of dogs treated with pacemaker implantation and surgery.

When To See A Vet For Sick Sinus Syndrome In Dogs?

  • Fainting /unconsciousness
  • Seizure
  • Tachycardia – an irregularly fast heartbeat
  • Bradycardia – an irregularly slow heartbeat

Food Suggestions For Sick Sinus Syndrome In Dogs

  • Lean, home-cooked, or boiled meats (chicken, beef, turkey, fish)
  • Green Leafy Veggies: Kale, cabbage, spinach, and swiss chard
  • Rice (brown rice or plain white, not flavored)
  • Whole Grains: Oats, Brown rice, barley, quinoa, and buckwheat
  • Fresh vegetables/fruit (carrots, green beans, banana, orange, apple, Blackberries, Raspberries, Blueberries, etc)
  • Fatty Fish such as Salmon, anchovies, tuna, Sardines, and Mackerel


Sick sinus syndrome in dogs is a progressive disease that affects the dog’s heart health and can limit its lifestyle. The present treatment modalities are targeted at treating the pain and decelerating the progression of the disease.

So, earlier detection of this progressive heart condition is the best option to begin a positive treatment plan.

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