Early Signs of Heart Disease in Dogs: Why Do they Matter for Pet Companies

Up to 75% of senior dogs have some form of heart disease, according to CVCA. Most of those cases go undetected. Not because dog owners aren't paying attention.

Because the early signs of heart disease in dogs do not look like a heart disease at all. They look like every other Tuesday, a walk that ended a little sooner, a cough that came and went, and breathing that ran slightly fast during the nap.

Heat disease has always been visible. We just didn’t have the right tools to measure it. Now, we do.

The gap between onset and diagnosis

Heart disease is one of the most common conditions in dogs, and according to the Cardiovascular Center for Animals (CVCA), nearly eight million dogs in the US have one form of it.

To put that in perspective, with 80 million dogs in the US, it means every 1 in 10 dogs has a heart disease. In senior dogs, that number goes up to 75%, three in four dogs.

Sadly, most of the cases go undetected until symptoms become obvious.

The problem is the timeline. VCA Animal Hospitals note that most dogs show no clinical signs until heart disease is advanced, and that earlier detection often depends on a veterinarian hearing a murmur during a routine exam. Many dogs never get that exam at the right time.

For your customers, the experience looks like this: a dog who sleeps a little more than usual. A cough that turns up at night. A walk that seems shorter than it used to. None of these are dramatic. All of them matter.

What the early signs look in real-life

The earliest signs of heart disease in dogs tend to be behavioral and easy to explain away.

Exercise intolerance is usually the first thing owners notice. The dog tires more quickly than before on the same route, stops for rests mid-walk, or refuses to play the way she used to. In warm weather this is especially pronounced, but it is not the heat doing it.

Coughing follows. Dogs with early heart disease tend to cough after rest or in the evening - a honking or gagging sound that owners sometimes describe as the dog trying to bring something up. It can look like a hairball. It is fluid beginning to accumulate near the lungs.

Elevated resting respiratory rate is the most measurable early warning. A healthy dog at rest breathes between 15 and 30 times per minute, according to FirstVet. When that number consistently exceeds 35 to 40 breaths per minute, the American College of Veterinary Internal Medicine (ACVIM) recommends contacting a vet. Dogs entering early congestive heart failure typically show a rising resting respiratory rate in the days before visible symptoms appear.

Restlessness and disrupted sleep often accompany these. A dog that cannot get comfortable at night, circles repeatedly before lying down, or seems unsettled in a position he usually finds easy - the body is working harder than it should.

Lethargy and reduced appetite arrive slightly later, as the heart works less efficiently and reserves are taxed.

The gap between "something is off" and an actual diagnosis can be weeks. During that window, disease progresses and treatment started earlier would make a measurable difference.

The EPIC study (Evaluation of Pimobendan In dogs with Cardiomegaly), published in the Journal of Veterinary Internal Medicine by Boswood et al. in 2016, found that treating dogs at the preclinical stage of mitral valve disease extended the asymptomatic period by an average of 15 months compared to placebo. The study followed 360 client-owned dogs across 11 countries and four continents. Its evidence was so conclusive that the trial was terminated early - it was considered unethical to continue withholding treatment from the control group.

Fifteen months is a significant number. For many small-breed dogs with mitral valve disease, that is a meaningful portion of their remaining lifespan.

Why continuous monitoring changes the window

A vet hears what is happening at one moment in time. What is happening at 3am, during a nap after a slow walk, or on a Tuesday when no appointment is scheduled - that has historically been invisible.

Wearable health monitors change that. By tracking heart rate and respiratory rate continuously, they give owners and vets a running picture of what a dog's body is doing across all conditions - awake, resting, sleeping, recovering from exercise.

A study published in Veterinary Sciences in March 2025 by Chuluunbaatar et al. at Jeju National University (doi: 10.3390/vetsci12040301) evaluated ballistocardiography (BCG) wearable technology for monitoring heart rate and respiratory rate in dogs. BCG readings correlated with ECG - the clinical gold standard - at r=0.97 and R²=0.94 for heart rate in awake dogs. The researchers concluded that BCG provides a non-invasive, continuous alternative to ECG that is both easier to apply and less physiologically stressful than methods requiring electrode placement on shaved skin.

This is not a marginal improvement over manual monitoring at home. It is the difference between a snapshot and a continuous record.

A single elevated respiratory rate count on one afternoon means something different from a rate that has risen five points over three days. The latter is actionable. The former is noise.

The business case for positioning around early detection

The global veterinary monitoring equipment market was valued at $568 million in 2024, according to Global Market Insights (September 2025), and is projected to reach $1.3 billion by 2034 at a CAGR of 9.1%. The drivers are not new - rising pet ownership, higher spend per animal, and pet owners treating their animals as family members who deserve the same standard of preventive care humans receive.

What has changed is the technology. Wearable, non-invasive, real-time health monitors now exist for dogs. They generate interpretable data from daily life, not just from a clinical visit. They give pet companies something to offer that did not exist five years ago: a product that addresses the specific moment every dog owner eventually faces - the moment something seems wrong, but there is nothing concrete to show the vet.

Pet companies that position around early detection are solving that problem. The owner who writes off a slower walk or an evening cough is not negligent. She simply does not have the information to act on. A product that provides that information, clearly and continuously, turns a vague unease into a specific signal she can bring to her veterinarian.

That is the category worth being in.

PuresPet PHH-23: continuous monitoring built around how dogs actually live

The PuresPet PHH-23 is built on BCG technology - the same method validated in the Chuluunbaatar et al. study cited above. It monitors heart rate, respiratory rate, and activity continuously around the clock, without shaving, electrode placement, or sedation.

Unlike manual respiratory rate monitoring - which requires a dog to be fully at rest, a patient owner, a timer, and the ability to count chest movements across an uninterrupted minute - the PHH-23 generates a continuous record that can be reviewed across days and weeks. Changes that appear gradual in retrospect are often missed entirely when observed only at single points in time.

For pet companies evaluating health monitoring products to bring to market, the PHH-23 offers clinically grounded, non-invasive technology that addresses a real and underserved need. Dogs' heart health is largely invisible to their owners right now. This product makes it visible.

Frequently Asked Questions

What are the first signs of heart disease in dogs?

The earliest signs are usually exercise intolerance, a persistent cough, usually at night or after rest, and an elevated resting respiratory rate. Most of these symptoms appear before any clinical diagnosis and often pet parents miss them.

At what age do dogs develop heart disease?

Acquired heart disease is more common in older dogs, with three of four senior dogs in the US having one form of heart disease. In small dogs, some prone to heart diseases like the Cavalier King Charles Spaniel and Dachshunds, the disease can start developing at six years of age.

Which dog breeds are most prone to heart disease?

Cavalier King Charles Spaniels, Miniature Schnauzers, Chihuahuas, Dachshunds, and Doberman Pinschers are some of the popular breeds with a high risk for a heart disease. Large breeds suffer more from dilated cardiomyopathy, while small and medium breeds develop mitral valve disease.

How do I check my dog's resting respiratory rate at home?

Count the number of times your dog's chest rises and falls over one minute while the dog is asleep or resting in a cool room. Each rise and fall counts as one breath. If you count more than 35 breaths during resting, contact your wet. Wearable monitors count it automatically and track it over time.

How long can a dog live after being diagnosed with heart disease?

This depends on the stage and type of disease at detection. Dogs identified at the preclinical stage - before congestive heart failure - generally fare significantly better than those diagnosed later. The EPIC study (Boswood et al., 2016, Journal of Veterinary Internal Medicine) found that beginning treatment at the preclinical stage extended the asymptomatic period by an average of 15 months compared to untreated dogs.

What does a heart disease cough sound like in dogs?

It is typically a dry, persistent cough that sounds like the dog is trying to clear its throat. It is most common at night or after rest. In later stages, it may become wetter as fluid accumulates in or around the lungs. Owners often describe it as a honking sound and sometimes mistake it for the dog trying to bring something up.

Can heart disease in dogs be prevented?

For acquired forms like mitral valve disease, there is no reliable prevention. Early detection, however, allows for earlier treatment, which meaningfully changes outcomes. Annual wellness exams, breed-specific screening, and continuous monitoring of resting heart rate and respiratory rate all improve the chance of catching the disease at a stage when intervention is most effective.