Canine Heart Disease Explained: 2025 Vet Guide to Diagnosis, Treatment & Modern Monitoring 🩺🐶❤️

By Dr. Duncan Houston BVSc

Hello! I’m Dr Duncan Houston, BVSc, veterinarian and founder of Ask A Vet. In this in-depth 2025 guide, we’ll explore the most common heart diseases in dogs—what they are, how they’re diagnosed and treated, and how new technologies, including telehealth, are changing the way we support our canine companions’ hearts.

1. 🫀 What Is Heart Disease in Dogs?

“Heart disease” covers a range of conditions affecting the heart’s valves, muscles, or rhythm, leading to reduced cardiac output, accumulation of fluid (congestive heart failure), abnormal heart rhythms, or decreased lifespan. The most common forms are:

• Degenerative Mitral Valve Disease (MMVD) – Valve deterioration causing blood leakage; typical in small breeds.
• Dilated Cardiomyopathy (DCM) – Thinning and dilation of the heart muscle, mainly in large breeds.
• Congestive Heart Failure (CHF) – The end-stage syndrome where reduced cardiac output leads to fluid buildup in the lungs or abdomen.
• Congenital defects, pericardial disease, and heartworm also contribute to heart disease in dogs.

2. 🐶 Degenerative Mitral Valve Disease (MMVD)

MMVD is the most common heart disease, particularly in Cavalier King Charles Spaniels, Cocker Spaniels, and Dachshunds. As the mitral valve deteriorates, leakage (regurgitation) increases, eventually causing left‑sided CHF.

• Clinical Stages

• A (At-risk): Breed predisposition, no murmur.
• B1: Murmur present, no structural changes.
• B2: Murmur with echocardiographic changes.
• C/D: Symptomatic CHF.

• Treatment by Stage

• B2: Pimobendan delays CHF onset.
• C/D: Diuretics (furosemide), ACE inhibitors, pimobendan, and sometimes spironolactone.
• Advanced: Transcatheter edge-to-edge repair (TEER) is an emerging surgical option.

3. 🐕 Dilated Cardiomyopathy (DCM)

DCM is most common in large breeds like Dobermans, Boxers, and Great Danes. The heart muscle becomes weak and the chambers dilate, leading to poor pump function, arrhythmias, and CHF. Both genetics and diet may contribute.

• Diagnosis

• Echo: Dilated chambers, decreased contractility.
• Holter: Detect dangerous arrhythmias like ventricular tachycardia.
• Genetic testing in predisposed breeds.

• Treatment

• Pimobendan, ACE inhibitors, and diuretics.
• Anti-arrhythmics as needed.
• Monitor and adjust medication with telemedicine.

4. 🏥 Congestive Heart Failure (CHF)

CHF is a syndrome caused by heart disease—either from MMVD or DCM—leading to fluid in the lungs (pulmonary edema) or abdomen (ascites), with clinical signs like coughing, difficulty breathing, fatigue, and swelling.

• Treatment Plan

• Diuretics (furosemide).
• ACE inhibitors, pimobendan, and spironolactone.
• Oxygen therapy and a low-sodium diet.
• Monitor kidney function and electrolytes.

5. 🩺 Diagnosis & Monitoring Tools

• Auditory exam for murmurs and gallops.
• Chest X-rays for heart size and fluid.
• ECG for arrhythmias.
• Echocardiography is the gold standard.
• Blood tests: Complete panel, NT-proBNP.

6. 💊 Medications & Therapies

• Pimobendan: Delays CHF in MMVD; cornerstone treatment.
• ACE Inhibitors: Reduce cardiovascular stress; benefit DCM and MMVD.
• Diuretics: Furosemide to control fluid accumulation.
• Anti-arrhythmics: To manage arrhythmias.
• Emerging therapies: Gene therapy for cardiac repair; longevity drugs (e.g. IGF-1 modulators) show promise.

7. 🏡 Home Monitoring & Lifestyle

• Track breathing rate, coughing, appetite, and energy.
• Maintain moderate exercise; monitor weight.
• Use telehealth for remote ECG uploads, medication reminders, and symptom check-ins.
• Regular veterinary follow-up every 6–12 months, tailored by disease stage.

8. 🌐 Telehealth & Technology in 2025

• Wearable ECG patches for continuous monitoring.
• AI adds real-time flagging of arrhythmias and structural changes.
• Holter data review through tele-neurology platforms.
• Virtual consults to reduce travel and stress.
• Medication and appointment reminders are integrated into pet-care apps.

9. 📈 Prognosis & Research Highlights

• Early pimobendan in MMVD significantly improves survival.
• VetCompass data confirms pimobendan's role in canine longevity.
• Diet-linked DCM cases have spurred FDA review.
• Longevity drugs like IGF-1 modulators may extend meaningful lifespan.

10. 🐾 Breed-Specific Notes

• MMVD: Cavaliers, Cockers, Dachshunds.
• DCM: Dobermans, Boxers, Great Danes.
• Healthy small breeds often develop MMVD; large breeds are more prone to DCM.

11. 💬 FAQs for Pet Parents

Can heart disease be reversed? 

While permanent reversal isn't possible, early meds can halt progression and improve quality of life.

Is my dog at risk? 

Breed and age are key risks. Regular vet exams help with early detection.

How do I know when to go to vet?

Seek care for new cough, difficulty breathing, fainting, or unusual lethargy.

Can diet affect heart disease?

Yes—especially in grain-free diets linked to DCM in some breeds.

12. ❤️ Ask A Vet Telehealth Integration

With Ask A Vet, you can:

• Upload ECG and echo images for remote cardiologist review.
• Get real-time medication reminders and health check prompts.
• Schedule virtual consultations for heart-related symptoms or changes.
• Link wearable monitor data directly into your vet’s dashboard.
• Coordinate care plans with your local vet, plus Ask A Vet specialists.

Download our app to keep your pup’s heart health in check—home-integrated expertise made easy. 🐾❤️

13. 🔚 Summary

Heart disease in dogs encompasses conditions ranging from valve degeneration (MMVD) to heart muscle weakening (DCM), progressing to CHF. With diligent diagnosis, stage-appropriate treatment, and modern tools—especially wearable tech and telehealth—many dogs live full lives in 2025 and beyond. Early detection, medications like pimobendan, ACE inhibitors, lifestyle adjustments, and innovative telemedicine ensure optimal outcomes. Partner with your vet and Ask A Vet to safeguard your dog's most critical organ—every heartbeat matters.

— Dr Duncan Houston, BVSc