Rapid Heart Rate in Dogs

A dog’s heart rate may increase for a variety of reasons, ranging from excitement or agitation to physical exertion. This is normal and will typically correct itself within a short period of time. However, if the abnormally rapid heart rate is sustained over a longer period, it may be indicative of a medical condition that requires veterinarian attention.

Tachycardia is defined as an abnormally rapid heart rate. Superventricular tachycardia typically arises from heart diseases, while ventricular tachycardia may be a result of heart disease, congenital defects, or other conditions. Ventricular tachycardia, in particular, is a serious condition, as it can lead to sudden collapse or death if the arrhythmia is not controlled.

Symptoms of tachycardia include:

• Excessive panting
• Shortness of breath
• Lethargy
• Weak pulse
• Fainting or collapse
• Disinterest and weakness during exercise
• Confusion

Types

Though a rapid heart rate may occur for a variety of reasons, this article focuses primarily on abnormally fast rates that require medical attention. There are two types of tachycardia, which are divided based on where they originate in the heart.

• Superventricular tachycardia - Also referred to as atrial tachycardia, supraventricular tachycardia originates in the atria, which is situated about the ventricles.
• Ventricular tachycardia - Ventricular tachycardia occurs within the ventricles, which are the chambers of the heart responsible for pumping blood. This condition may result in sudden collapse or death and is considered life-threatening if not treated.

Superventricular tachycardia is often caused by heart disease or systemic disease. Ventricular tachycardia can occur for a wider variety of reasons, including:

• Congenital defects, such as subaortic stenosis
• Heart disease, such as dilated cardiomyopathy
• Drug overdose
• Congestive heart failure
• Gastrointestinal disease
• Splenic disease
• Myocarditis
• Pancreatitis

Depending on the underlying cause, certain breeds tend to be predisposed to the condition. Boxers, in particular, are more at risk of developing ventricular tachycardia.

As with most veterinarian visits, the doctor will conduct a thorough physical examination of your dog, which may include blood tests and a urinalysis both to narrow down potential causes for your dog’s symptoms and to assess your dog’s overall health. As part of this examination, the veterinarian will need a full history, so be prepared to provide information on the onset and duration of your dog’s clinical signs.

Tachycardia itself is diagnosed via electrocardiography (ECG or EKG), which assesses the electrical activity of the heart. Based on the results of the electrocardiograph exam, the veterinarian will be able to determine your dog’s heart rate, though a Holter monitor worn for 24-hours may be needed for a definitive diagnosis. If the veterinarian is still not having success identifying the core issue, further testing, such as an echocardiogram or a complete blood count, may be required to discover the cause of the rapid heart rate.

The vets primary goal of administering treatment is to control the arrhythmia, especially in dogs that are showing clinical signs of tachycardia. Antiarrhythmic therapy involves administration of medication, such as lidocaine and sotalol, with dosage varying depending on your dog’s condition and reaction. In severe cases, a defibrillator may be needed to bring the heart beat back to normal.

Medical treatment may be decreased over time if your dog responds well, and the arrhythmia is under control. However, the underlying cause for the tachycardia will need to be addressed in order to ensure long-term survival. Though medication can be used to manage ventricular tachycardia, it does not completely remove the possibility of sudden collapse or death.

Radioblation techniques may sometimes be used to treat supraventricular tachycardias.

Once your dog is back at home, you will need to continue monitoring his or her heart rate. A Holter monitor is particularly useful for this since it can be worn without hindering your dog’s daily activities and provides you with reliable information regarding your dog’s heart. The veterinarian will need this information to determine whether or not your dog’s arrhythmia is under control, as well as the level of danger he or she may still be in.

Depending on the treatment needed for any underlying conditions, you may need to return to the veterinarian periodically for follow-up exams. Your dog may be weaned from the antiarrhythmic drugs if the tachycardia is under control. The prognosis for superventricular and ventricular tachycardia is typically good, as long as the underlying cause is addressed and the tachycardia is resolved or controlled.

A rapid heart rate could be symptomatic of a serious medication condition. To avoid high vet care expenses, secure pet health insurance today. The sooner you insure your pet, the more protection you’ll have from unexpected vet costs.