Overview

Acquired heart disease involves changes in the valves or heart muscle over time and is common in older dogs and cats. The conditions most frequently seen differ between the species.

Myxomatous mitral valve disease (MMVD)

The most common heart disease in older small and medium-sized dogs. The valve between the left atrium and ventricle gradually thickens and allows blood to leak backward. Progression can lead to pulmonary edema, so regular monitoring matters.

MMVD describes degeneration of mitral valve tissue. When this prevents the valve from closing properly and blood flows backward, it causes mitral regurgitation. We assess valve changes, leakage and heart size together.

Dilated cardiomyopathy (DCM)

Seen mainly in large dogs, DCM involves ventricular dilation and thinning of the walls with reduced pumping function. Associations with some diets have been reported, so we also review feeding history.

Hypertrophic cardiomyopathy (HCM)

The most common feline heart disease, HCM involves thickening of the left ventricular wall and impaired relaxation. Early disease may have no obvious signs and may first be detected after sudden breathing difficulty or hindlimb paralysis from a clot.

Restrictive cardiomyopathy (RCM)

A feline condition in which the ventricles do not relax normally, impairing filling. Symptoms and imaging findings can overlap with HCM, making detailed imaging important for differentiation.

A dog relaxing at home
Everyday companionship · K / Pexels

Our diagnostic approach

After reviewing history, examination, auscultation and previous records, we select relevant blood tests, chest X-rays, Echocardiography, abdominal ultrasound, ECG to answer the current clinical question. Not every patient receives the same tests in the same order. We explain the selected items and estimated costs and proceed with your agreement.

Possible tests

Auscultation / Respiratory rate

Assess murmur grade and resting respiratory rate (SRR).

Possible tests

Comprehensive blood tests / Cardiac biomarkers

CBC, serum chemistry, electrolytes, thyroid hormone (T4) and cardiac biomarkers (NT-proBNP and others) assess overall health and cardiac strain.

Possible tests

Digital X-rays

Assess cardiac silhouette size (VHS) and pulmonary edema.

Possible tests

Echocardiography

Quantify valve and ventricular function with Doppler and determine the ACVIM stage.

Possible tests

abdominal ultrasound

Identify effects of reduced cardiac function, such as liver congestion or ascites, and concurrent kidney, liver or adrenal disease common in older pets. Findings directly inform medication choice and dosing.

Possible tests

Electrocardiography (ECG)

Assess rhythm and electrical activity when arrhythmias, unsteadiness or fainting are suspected.

Noninvasive blood pressure measurement and Holter monitoring for 24 hours or longer may be added when needed.

Treatment and management

Treatment varies by stage. We explain options based on ACVIM guidelines and the patient's current stage and condition.

Medication

Stage-appropriate combinations may include diuretics for pulmonary edema, vasodilators and inotropes. Doses are adjusted while monitoring kidney function and electrolytes.

Home monitoring — Resting respiratory rate (SRR)

Recording your pet's breathing rate during sleep can help detect early signs of pulmonary edema. We provide measurement guidance and a record sheet.

Diet / Daily routines

We advise whether sodium restriction is needed, suitable activity levels and medication timing, adapted to your pet and your daily routine.

Managing concurrent conditions

We monitor kidney and liver function during long-term cardiac medication and consider other chronic conditions common in older pets, including endocrine and musculoskeletal disease.

Reference. Abbreviations used here: MMVD, myxomatous mitral valve disease; DCM, dilated cardiomyopathy; HCM, hypertrophic cardiomyopathy; ACVIM, American College of Veterinary Internal Medicine.

FAQs

Does a heart murmur always require medication?
No. We assess echocardiography alongside other indicated imaging and clinical findings, then discuss whether the disease has reached a stage requiring medication.
Will medication be lifelong?
Many acquired heart diseases are progressive and require long-term medication. Drug choices and doses are adjusted as the stage and your pet's condition change.
Does a cat without obvious symptoms need screening?
HCM can occur at any age or in any breed, even with normal auscultation. Echocardiography may be considered for a murmur, gallop, arrhythmia, breathing changes, family history, breeding plans or breed predisposition. Timing and repeat intervals depend on individual risks and previous findings.
How do I measure resting respiratory rate?
When your pet is asleep or resting comfortably, count one rise and fall of the chest as one breath for a full minute. The rate is usually below 30. Repeated readings of 40 or more warrant veterinary assessment.
What are the treatment costs?
The estimate depends on tests and prescriptions. You can refer to our legally required published Fee schedule. We explain the final estimate and other expected costs before proceeding and perform only agreed items.

Read more about each condition

Detailed clinical information on the main acquired heart conditions in this category.