Is Your Dog’s Heart Racing? The Dangerous Truth About Canine Tachycardia

Introduction

A dog’s normal resting heart rate ranges between 60 to 160 beats per minute, depending on the dog’s size. Tachycardia refers to an abnormally rapid heart rate, usually above 160 beats per minute in dogs. Monitoring a dog’s heart rate is important because an elevated heart rate can be an early indicator of underlying health issues.

Some common causes of tachycardia in dogs include thyroid disease, anemia, fever, dehydration, shock, heart disease, poisoning, and certain medications. An abnormally high heart rate puts stress on the heart and reduces blood flow to vital organs. If left untreated, it can lead to more serious cardiac complications. By routinely checking a dog’s heart rate at home and recognizing when it is higher than normal, owners can get veterinary care sooner and prevent further medical problems.

Normal Heart Rate

A dog’s normal resting heart rate will vary somewhat based on their breed and size. Here are some general guidelines (beats per minute) for normal resting heart rates in dogs:

chart showing normal dog heart rate ranges

Small dogs and puppies: 120-160 bpm (bevsvt.com).

Medium dogs: 70-110 bpm (dixieanimalhospital.com).

Large dogs: 60-100 bpm (toegrips.com).

Giant breed dogs: 60-90 bpm.

Puppies can have resting heart rates up to 220 beats per minute at 2 weeks old, which declines as they mature (dixieanimalhospital.com).

Causes

There are several potential causes for an elevated heart rate in dogs, including:

  • Fever – A fever causes an increase in metabolism and heart rate as the body works to fight infection [1].
  • Dehydration – Dehydration thickens the blood, forcing the heart to pump faster to circulate blood through the body [2].
  • Shock – Blood pressure drops in shock, leading to faster heart rate as the body tries to compensate [3].
  • Heart Disease – Heart conditions like dilated cardiomyopathy, arrhythmias, and valve disorders can cause rapid heart rates [1].

Symptoms

Some of the most common symptoms of a dangerously high heart rate in dogs include:

Rapid breathing – Dogs with a rapid heart rate often breathe faster than normal. Their breathing may seem strained or labored as their body tries to get more oxygen.

Weakness – A racing heart can leave dogs feeling weak or lethargic. They may seem unable to play or exercise as normal.

Pale gums – The gums may appear light pink or white instead of a healthy dark pink color. This indicates poor blood flow.

Restlessness – Dogs may seem anxious or distressed due to discomfort from the rapid heartbeat.

Collapse – In severe cases, dogs may collapse or faint due to insufficient blood flow to the brain and other organs.

Other symptoms can include panting, coughing, vomiting, diarrhea, and cool extremities. Severe cases require immediate veterinary care to avoid shock or death. Milder cases still require a vet visit to determine and address the underlying cause (Source).

dog exhibiting symptoms like pale gums

Dangers

Elevated heart rates in dogs can be dangerous and even life-threatening if left untreated. Some of the most concerning dangers of a high heart rate in dogs include:

  • Fainting – A rapid heart rate can decrease blood flow to a dog’s brain, causing them to faint or collapse.
  • Seizures – The lack of proper blood flow can cause seizures in dogs with dangerously high heart rates.
  • Heart failure – If a high heart rate persists, it can lead to an enlarged heart and eventual congestive heart failure.
  • Damage to other organs – With decreased blood flow, other major organs like the kidneys and liver can be damaged over time.

Left untreated, an abnormally rapid heart rate can have devastating effects. It’s critical that dog owners monitor their pet’s heart rate and watch for any concerning symptoms that may indicate a problem. If caught early, many heart conditions can be managed with medication or other treatments recommended by a veterinarian.

Diagnosis

If a dog is showing concerning symptoms like panting, shaking, weakness or collapse, the first thing a veterinarian will do is check the dog’s heart rate and rhythm by taking their pulse. A normal heart rate for dogs ranges from 60 to 160 beats per minute, but anything consistently over 160 bpm is considered dangerously high.

veterinarian listening to dog's heart

The veterinarian will listen to the dog’s heart and lungs with a stethoscope to check for any arrhythmias or murmurs. They may also examine the dog’s gums and tongue, checking for pale color indicating anemia or poor circulation.

Other diagnostic tests vets commonly use include:

  • Blood tests to check electrolyte levels and look for signs of infection or imbalances
  • An ECG to evaluate the heart’s electrical activity and identify any irregular rhythms
  • Chest X-rays to check for an enlarged heart or fluid in the lungs

The results of a physical exam and diagnostic testing will allow the vet to pinpoint the cause of the rapid heart rate and guide appropriate treatment.

Sources:

https://wagwalking.com/condition/rapid-heart-rate

https://www.petmd.com/dog/conditions/cardiovascular/c_dg_rapid_heart_beat

Treatment

The main treatment goals for dangerously high heart rates in dogs are to address any underlying cause and to stabilize the heart rate. Some common treatments include:

Address Underlying Cause: If an underlying condition like anemia, infection, pain, etc. is causing the rapid heart rate, treating that condition may help resolve the tachycardia. For example, administering antibiotics for an infection or providing pain relief medication.

Medications: Vets may prescribe medications that slow electrical conduction in the heart to reduce the heart rate. Common medications used include beta blockers like atenolol or calcium channel blockers like diltiazem. The dosage and specific medication depends on the individual dog.

Oxygen Therapy: If the rapid heart rate leads to low oxygen levels, providing supplemental oxygen through a face mask or low-flow nasal cannula can help support respiratory function.

In extreme cases where the heart rate is dangerously high and unstable, medications may be given intravenously to rapidly decrease the heart rate along with supportive care like oxygen therapy. The goal is stabilizing the heart rate until the underlying cause can be treated.

Prevention

There are several ways to help prevent your dog from developing a dangerously high heart rate:

ways to prevent rapid heart rate in dogs

Keep your dog cool during hot summer months. Dogs are susceptible to heat stroke, which can cause a rapid heart rate. Make sure your dog has access to shade and fresh water. Avoid strenuous exercise on very hot days. Cool your dog down with a fan or wet towels if showing signs of overheating (citation: https://wagwalking.com/condition/rapid-heart-rate).

Ensure your dog stays well-hydrated year round. Dehydration places stress on the cardiovascular system. Make clean water readily available and encourage your dog to drink frequently (citation: https://www.petmd.com/dog/conditions/cardiovascular/c_dg_rapid_heart_beat).

Reduce stress for your dog. Stress and anxiety can spike your dog’s heart rate. Create a calm home environment, avoid shouting, and use pheromone diffusers if your dog is highly strung. Exercise and play can also help relieve stress (citation: https://wagwalking.com/condition/rapid-heart-beat).

When to See a Vet

If your dog’s resting heart rate is consistently over 160-180 beats per minute (bpm) in small dogs or 140-160 bpm in large dogs, you should take them to see a vet as soon as possible. A heart rate in this range indicates a dangerously high level that requires urgent medical attention. Some specific signs that signal the need for immediate vet care include:

  • Resting heart rate over 180 bpm in small dogs
  • Resting heart rate over 160 bpm in large dogs
  • Rapid heartbeat even when resting
  • Labored breathing or respiratory distress
  • Weakness or lethargy
  • Collapsing or loss of consciousness

According to WagWalking, a heart rate over 180 bpm in small dogs is considered a “medical emergency.” Waiting too long can worsen your dog’s condition and lead to complications. Getting prompt veterinary treatment greatly improves the chances of stabilizing your dog’s heart rate and allows the vet to address any underlying cause.

Conclusion

In summary, a normal heart rate for dogs ranges from 60 to 160 bpm depending on their size. Small dogs tend to have a faster heart rate. Tachycardia refers to a heart rate over 160 bpm and can be caused by underlying conditions like heart disease, fever, dehydration, pain, shock, anemia, infections, and certain medications. Symptoms include panting, weakness, pale gums, breathing difficulty, and collapse. Having a high heart rate for an extended time puts strain on the heart and can lead to congestive heart failure. If your dog has a concerning heart rate or any symptoms of tachycardia, take them to the vet for an EKG and bloodwork to diagnose the cause. Treatment depends on the underlying condition but may include addressing dehydration, infection, pain management, discontinuing certain medications, surgery, and heart medications. Going forward, monitor your dog’s heart rate and watch for any concerning symptoms. Seek veterinary care promptly if their heart rate remains dangerously high.

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