Understanding Heart Disease in Dogs

If your dog has just been diagnosed with a heart condition, or you’ve noticed changes like persistent coughing, unusual fatigue, or fainting, it’s natural to feel worried. Heart disease in dogs is more common than many owners realize, and while it’s a serious topic, understanding what’s happening and what comes next can help you feel more prepared.

What is heart disease in dogs?

Heart disease in dogs is any condition that reduces the heart’s ability to pump blood efficiently. It can be congenital (present at birth) or acquired (developing later in life). It’s one of the more common health conditions in dogs, particularly in seniors, and while it can impact quality of life, many dogs go on to live well for years with early detection and the right management in place.

Types of heart disease

There are several common heart conditions in dogs:

• Mitral valve disease (MMVD): The heart valve thickens and leaks, leading to a murmur. This is the most common form in smaller, older breeds like Cavalier King Charles Spaniels and Dachshunds.
• Dilated cardiomyopathy (DCM): The heart muscle weakens and stretches, making it harder to pump blood. Large breeds like Dobermans, Great Danes, and Boxers are most affected.
• Heartworm disease: Caused by parasitic worms that damage the heart and lungs. It’s preventable with regular medication.
• Arrhythmias: Irregular heart rhythms, often seen in Boxers and German Shepherds, can cause fainting or sudden collapse.
• Congenital defects: Birth defects like patent ductus arteriosus or pulmonic stenosis are detected early if present.

Symptoms of heart disease in dogs

Heart disease often creeps up slowly, showing subtle symptoms that worsen over time. Here’s what to watch for:

• Persistent coughing or rapid breathing
• Exercise intolerance (difficulty keeping up during walks or playing)
• Lethargy or unusually low energy
• Fainting or collapsing
• Bloating or a swollen abdomen
• Weight loss and reduced appetite
• Behavioral changes, like restlessness or difficulty sleeping

If you notice any of these signs, especially if they’re getting worse, it’s worth a vet visit sooner rather than later. Many of these symptoms don’t appear until the disease has already progressed, which is why routine checkups matter even when your dog seems fine.

Diagnosis of heart disease in dogs

Heart disease is typically first suspected during your dog’s annual checkup if the vet detects a heart murmur or irregular heartbeat. From there, additional tests may include:

• Chest X-rays: Show the size and shape of the heart and check for fluid in the lungs.
• Echocardiogram: An ultrasound of the heart to visualize its structure and function.
• Electrocardiogram (ECG): Measures electrical activity to detect arrhythmias.
• Blood panels: Check overall organ function and heart-specific markers.
• Heartworm test: Determines if worms are the underlying cause.

For breeds with a known predisposition, asking your vet about proactive screening before any symptoms appear is worth the conversation.

Treatment of heart disease in dogs

While most heart diseases aren’t curable, they can often be managed well with appropriate care. Your vet may recommend:

• Medications: Pimobendan (helps the heart pump effectively), ACE inhibitors (reduce blood pressure), and diuretics (manage fluid retention).
• Lifestyle changes: Moderate exercise and a low-sodium diet tailored to their condition.
• Heartworm treatment: If heartworms are present, eliminating them will be a top priority.
• Surgery: In cases of congenital defects, corrective surgery may be needed.

The goal of treatment is to reduce symptoms, slow progression, and keep your dog comfortable.

It’s important to note that treatment plans are highly individual, and close communication with your vet or a veterinary cardiologist will be key to finding the right approach for your dog.

Does pet insurance cover heart disease?

Yes, Lemonade pet insurance can cover heart disease, as long as it’s not a pre-existing condition. This means that your dog didn’t show signs or symptoms of the condition until after your policy was in effect, and your waiting periods passed.

Managing a long-term heart condition involves regular vet visits, specialist consultations, and medications that add up over time, and having coverage in place means one less thing to worry about. A base accident and illness policy can cover the diagnostics, treatments, and medications for eligible conditions. Plus you can customize your policy to add additional coverage, like Lemonade’s Visit Fee add-on, which means exam fees from follow-up and specialist appointments are covered alongside everything else.

For breeds with a known predisposition, getting coverage in place before any symptoms appear is especially important.

Before we go

A heart disease diagnosis can feel like a lot to take in, but you’re not navigating it alone. Stay close to your vet, ask questions at every stage, and don’t wait on routine checkups. Early detection genuinely makes a difference with heart conditions. Many dogs with heart disease go on to have good quality of life with the right management in place.

Focus on what you can do today, and take it one step at a time.

Frequently Asked Questions

A few quick words, because we <3 our lawyers: This post is general in nature, and any statement in it doesn’t alter the terms, conditions, exclusions, or limitations of the policies issued, which differ according to your state of residence. You’re encouraged to discuss your specific circumstances with your own professional advisors. The purpose of this post is merely to provide you with info and insights you can use to make such discussions more productive! Naturally, all comments by, or references to, third parties represent their own views, and Lemonade assumes no responsibility for them. Coverage may not be available in all states. Please note that statements about coverages, policy management, claims processes, Giveback, and customer support apply to policies underwritten by Lemonade Insurance Company or Metromile Insurance Company, a Lemonade company, sold by Lemonade Insurance Agency, LLC.  The statements do not apply to policies underwritten by other carriers.