Irregular Heart Rhythms in Dogs

Irregular heart rhythm is often discovered by a routine veterinarian visit because there are rarely any noticeable symptoms. You may notice:

• Breathing trouble
• Lethargy
• Unsteadiness
• Losing consciousness
• Weight loss
• Seizures
• Confusion

 Types

• Accelerated idiojunctional rhythm is an abnormal heart rhythm caused by a faulty impulse from the junction between the ventricles and the atria. It is recognized by a heart rate of 60 to 100 beats per minute.
• Accelerated idioventricular rhythm is an increased heart rate from the ectopic ventricle. It is faster than the normal beat, but less than 100 beats per minute.

A thorough examination or your dog will be done with special care taken to get his heart rate and blood pressure. Let your veterinarian know everything you have noticed about your dog’s symptoms, diet, exercise routine, and anything else you think is important. If you feel that your dog has been acting different, you are the only one who can describe it for him.  

The veterinary technician will take blood and urine to get a CBC, blood chemistry panel, electrolytes, thyroid test, and blood glucose level.

 An electrocardiography (ECG) is the most important test that must be done to find the problem, if there is one. This will show fusion beats, missing P-wave, ventricular complexes, and QRS complexes more than 120ms. He will also need radiographs (x-rays) and an ultrasound to rule out physical cardiac abnormalities, tumors, or other anomalies. If the abnormality cannot be detected, the veterinarian may have you use a Holter monitor to get readings of your dog’s heart rhythm over a 24-hour period from home.

The treatment your veterinarian chooses depends on the underlying disorder, such as: 

Pancreatitis

• This is usually a cause for hospitalization depending on the severity of the attack. The veterinarian  will provide anti-nausea medicine, IV fluids, and rest for one to two days. If the attack is mild, the veterinarian will prescribe a diet that is low in fat and an enzyme supplement.

Insufficient Oxygen in the Blood (Hypoxemia)

• Hypoxemia is treated with oxygen and more tests to determine the cause of the condition. The veterinary caregiver may decide to hospitalize your dog until he is stable. Once he finds the cause of the hypoxemia, he will discuss treatment with you.

Heart Disease

• There are many types of heart disease caused by anything from diet to congenital defects. Because of this, the treatment for heart disease can be one of many, from a new food plan to surgery. The veterinarian will have to perform more tests to find the type and cause of the heart disease before it can be treated.

Electrolyte Imbalance

• The initial treatment for an imbalance of your dog’s electrolytes that is enough to trigger an irregular heart rhythm is IV fluids to restore his electrolyte levels. The veterinary team will also need to do some more tests to determine the reason for the imbalance. This disorder can be caused by many illnesses, from dehydration to diabetes.

Unknown Origin

• Irregular heart rhythm of unknown origin rarely warrants any medication or treatment unless it causes symptoms. The veterinarian will want to continue to monitor your dog’s blood pressure and get regular ECG recordings.