Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.

Rapid Heart Rate in Dogs

Sinus Tachycardia in Dogs

Sinus tachycardia (ST) in dogs is characterized by a sinus rhythm, or heartbeat, occurring at a faster rate than normal: exceeding 160 beats per minute (bpm) in standard sized dogs, 140 bpm in giant breeds, 180 bpm in toy breeds, and 220 bpm in puppies. The fluctuations in heart rate typically involve a reciprocal interplay between the parasympathetic and sympathetic divisions of the autonomic nervous system.

Excessive tachycardia can impede cardiac output by shortening the diastolic filling time, the period during which the heart chambers dilate and fill with blood between heartbeats. Especially in hearts afflicted with disease, the elevated heart rate may not adequately compensate for reduced volume, leading to diminished cardiac output, decreased coronary blood flow, and an accompanying rise in oxygen demands. Sinus tachycardia is the most prevalent benign arrhythmia observed in dogs and is frequently encountered as the primary rhythm disturbance in postoperative patients.

Symptoms and Types

In many cases, there are no noticeable clinical signs as the condition serves as a compensatory reaction to various stresses.

If linked with primary cardiac disease, reported symptoms may include weakness, exercise intolerance, or episodes of unconsciousness.

Presence of pale mucous membranes may indicate association with anemia or congestive heart failure.

Fever might accompany the condition.

When sinus tachycardia is linked with primary cardiac disease, signs of congestive heart failure, such as shortness of breath, coughing, and pale mucous membranes, may manifest.



  • Exercise
  • Pain
  • Restraint
  • Excitement

Anxiety, anger, fright

  • Pathological
  • Fever
  • Congestive heart failure
  • Chronic lung disease
  • Shock
  • Presence of fluid in the chest
  • Anemia
  • Infection/sepsis
  • Low oxygen levels/hypoxia
  • Pulmonary blood clot
  • Low blood pressure
  • Reduced blood volume
  • Dehydration


  • Risk Factors
  • Thyroid medications
  • Primary cardiac diseases
  • Inflammation
  • Pregnancy


Due to the multitude of potential causes associated with this condition, diagnosing and distinguishing it from similar diseases can be challenging. Your veterinarian is likely to employ a method known as differential diagnosis. This approach involves a thorough examination of visible symptoms, systematically ruling out each of the more common causes until the correct disorder is identified and can be treated effectively.

Your veterinarian will conduct a comprehensive physical examination of your dog, considering the history of symptoms provided by you and any potential incidents that may have precipitated the condition. A comprehensive blood profile, including chemical blood analysis, complete blood count, and urinalysis, will be performed to detect any blood infections or organ disorders (e.g., heart, kidneys).

Additionally, your veterinarian may request chest X-rays to detect indications of primary cardiac disease or tumors. An electrocardiogram (ECG or EKG) is crucial for assessing the electrical activity in the heart muscles, which can reveal abnormalities in cardiac electrical conduction and structural cardiac diseases affecting the heart’s function. Ultrasound and angiography are valuable for evaluating adrenal masses. A thyroid scan may also be conducted to assess your dog for hyperthyroidism.


Once a diagnosis has been confirmed, your veterinarian will formulate a treatment plan for your dog. The primary focus of treatment will be addressing any underlying cause that has been identified.

Living and Management

The management of your dog post-diagnosis will vary depending on the specific disease identified as the cause of sinus tachycardia. If your dog is negatively impacted by the elevated heart rate, limiting its activity to prevent excessive increases in heart rate may be necessary. However, this measure should only be implemented if deemed beneficial for your dog’s well-being.

Scroll to Top