None of us want our precious pets to get sick, but it's a reality that we must face from time to time. Heart issues are common in mature cats and dogs, so it's important to know what to look for, allowing you to catch issues earlier rather than later. From the normal and common to the abnormal and dangerous, let's get to the bottom of arrhythmias in pets.

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  1. Types of Arrhythmias in Cats and Dogs
  2. What Causes Arrhythmias in Pets
  3. What Are the Symptoms of Arrhythmias in Cats and Dogs
  4. How Are Arrhythmias Treated in Pets
  5. How Can the Emergency Fund Help with Treatment
  6. Conclusion

Types of Arrhythmias in Cats and Dogs

There are several different types of arrhythmias, affecting different parts of the heart and manifesting themselves in different ways. Some are common; others are (thankfully) very rare, but they almost all have one thing in common: they have the potential to be deadly. Thankfully, with pet cameras and other pet tech these days, you can keep an eye on your furry family members 24 hours a day and catch any issues quickly.

The most common types of arrhythmias in cats and dogs are:

Sinus Arrhythmia

When dogs and cats breathe — inhale and exhale — their heart rate changes. During inhalation, the heart beats a little faster. When your furry friend exhales, the heart beats a little slower. Although this is a type of arrhythmia, it is harmless and normal and shows that the heart is working just as it should.

There are a couple of other sinus-based arrhythmias:

  • Sinus Bradycardia: heart rate slower than usual;
  • Sinus Tachycardia: heart rate faster than usual.

Atrial Fibrillation

This type of arrhythmia is more common in dogs than in cats. It is characterized by very fast heart twitches or contractions, often described by experts as "tennis shoes in the clothes dryer," which cause a very fast heart rate.

Atrial fibrillation, also known as A-fib or AF, can have serious long-term effects if not investigated and untreated, such as disruption to blood circulation. Cardiac output is also severely reduced as a result of the ventricles having less time to fill. Your pet may experience dizziness or fainting spells, complete collapses, blood clots, and several other serious problems.

Cats and dogs can also experience atrial flutters, which cause your pet's heart to beat in a regular rhythm but faster than usual.

Ventricular Tachycardia

Ventricular tachycardia, also known as VTech, can be deadly and requires urgent medical attention. As the name suggests, the issue stems from the ventricles of the heart, causing a much faster heart rate. Untreated, VTach can lead to fainting spells and complete collapses.

The right and left ventricles make up the bottom half of the organ, and they pump blood to separate parts of the body.

  • Left ventricle: pumps blood to the entire body, minus the lungs;
  • The right ventricle: pumps blood to the lungs only.

It's also possible for your pets to suffer from ventricular fibrillation (VFib), which causes an irregular and chaotic heart rate.

Premature Beats

Premature beats are just as they sound: heartbeats that come just a second too soon. Medically, they're known as depolarizations or premature complexes, and Animal Specialty Hospital research shows they can be caused by abdominal issues, parasites (such as ticks), and heart disease. Alone, these early beats aren't usually a cause for concern, but if they happen regularly, the need for action increases. Treatment is also necessary for premature beats alongside other issues, such as ventricular tachycardia and atrial fibrillation.

Supraventricular premature beats, also known as SVPC or SVPD, arise in an area just above the ventricles of the heart. Ventricular beats, also known as PVCs, VPDs, or VPCs, arise directly from the heart ventricles below.

Atrioventricular Block

When the atria and ventricles lose the ability to connect via electrical impulses, this type of arrhythmia can occur. Also known as heart block, AV block, and atrioventricular block, it has three degrees of seriousness: 1st, 2nd, and 3rd degrees, with the 3rd degree being the most serious (high grade).

This type of arrhythmia slows the heart rate of your pets, which can lead to them collapsing and fainting. Symptoms include lethargy, no interest in play or activities, and sleeping or lying down more often than usual.

What Causes Arrhythmias in Pets

The cause of your pet's arrhythmia will depend on the type, which part of the organ is affected, and other health concerns. Atrial fibrillation often accompanies underlying heart issues in both cats and dogs, such as cardiomyopathy, birth-present heart disease (rare), disease of the heart valves, sick sinus syndrome, long QT syndrome, and Wolf-Parkinson-White syndrome (WPW), just to name a few.

Although there are other potential causes of arrhythmias in dogs and cats, they usually go hand-in-hand with conditions that affect the heart, such as heart disease.

What Are the Symptoms of Arrhythmias in Cats and Dogs

Once again, the type of arrhythmia will dictate the symptoms your pets will display. Slowing of the heart usually comes with decreased energy and interest because the heart can't cope with activity, but different heart conditions come with their own set of symptoms.

The most common symptoms across all types of arrhythmias include:

How Are Arrhythmias Treated in Pets

When you take your furry friend to the vet, they will be treated appropriately for the type of arrhythmia they have. Because arrhythmias are frequently diagnosed with other underlying heart issues, your pet will also receive treatment for those. Giant and large-sized dogs often respond better to beta-blockers, but pacemakers are necessary for other pets. With the right diagnosis, the right treatment can be administered.

How Can the Emergency Fund Help with Treatment

Arrhythmias have the potential to be life-threatening to your pampered pets, so make sure you're prepared for all emergencies with Petcube's Emergency Fund. It'll cost you less than $1 per day, give you $3,000 worth of vet cover for emergencies, and protect up to six pets in your household. And that's not all...

Signing up for the Emergency Fund unlocks access to veterinarians around the clock, 24/7, no matter what the issue. And, because you're one of our loyal blog readers, follow this link to get an exclusive 27% off.


When they have the potential to be deadly, arrhythmias in cats, dogs, or even yourself are not the kind of issues you should ignore. They can also make your pet uncomfortable, unwell, and unhappy for quite a while before you notice. Routine checkups will catch any issues as quickly as possible, leading to prompt treatments.

Your pet can't get any kind of treatment until you take them to the vet.

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