Stay one step ahead with screening for cardiac disease in general practice.

Preclinical cardiac disease is exactly what it says on the tin – although it is sometimes worth stating the obvious! By its very nature, this stage lacks recognisable symptoms that might otherwise warn of a brewing problem.

Gone are the days of hearing a heart murmur and waiting to see if clinical signs appear. We now have robust evidence showing that a proactive approach to cardiac disease can significantly extend both lifespan and quality of life. What pet owner wouldn’t want their beloved family member to stay well for longer – especially with more years free from visible illness?

In today’s increasingly digital world, pet owners are more informed than ever – but not always with the correct information. At the same time, as the cost of living rises, more clients are trying to plan ahead and budget wisely. This creates the perfect opportunity to get even more vets and nurses on board with early education and owner engagement, rooted in evidence-based medicine – not social media scaremongering or questionable internet forums!

Luckily, HeartVets are here to provide you with an overview on the key screening tools you can bring to your clinical practice. This article is a basic outline of the most common diseases, but if you want to dive deeper into detail, keep an eye on our website for upcoming CPD and all our current webinars – we’ve got you covered!

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Who Is Most Likely to Benefit from Cardiac Screening?

At-risk dog breeds

We often think of acquired cardiac disease (affecting middle aged and older patients) in two broad groups: “small dog disease” (DMVD) and “big dog disease” (DCM/ARVC). There is a crossover of breeds that can get both though, so watch out.

Here’s a quick guide:

• Small dogs – Degenerative Mitral Valve Disease (DMVD): Cavalier King Charles Spaniel, Chihuahua, Terrier breeds, Bichon Frise, Whippet, Shih Tzu, Toy Poodle, Miniature Schnauzer (or crossbreeds of any of the above!)
• Large dogs – Dilated Cardiomyopathy (DCM): Doberman, Irish Wolfhound, Deerhound, Rhodesian Ridgeback, Flatcoat Retriever, Standard Poodle, Bulldog, Rottweiler, Great Dane, Newfoundland, Bernese Mountain Dog
• Large dogs – Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): Boxer, Dogue de Bordeaux, Bulldog
• The ones that might catch you out – both DMVD or DCM can be seen in: Spaniels, Labradors, Pointers, Weimaraners, Sighthounds, Golden Retrievers

As with acquired disease, any breed or crossbreed can be born with congenital cardiac disease. Some types of disease are more common in specific breeds, such as:

• Patent ductus arteriosus (PDA): Cockerpoo, Cocker Spaniel, Maltese, German Shepherd
• Pulmonic stenosis (PS): Labrador, English Bulldog, French Bulldog, Miniature Schnauzer
• Aortic stenosis (AS): Boxer, Rottweiler, Bull Terrier, Golden Retriever, Bull Mastiff
• Mitral or tricuspid dysplasia: Labrador, Bull Terrier, Dogue de Bordeaux

At-risk cat breeds

• Hypertrophic Cardiomyopathy (HCM): While most of the cats we see are Domestic Shorthairs, HCM is also seen in: Maine Coon, British Shorthair, Sphynx, Ragdoll

When Should Screening Be Discussed?

Routine appointments

Start the conversation early – especially as pets reach the ‘typical’ age brackets for common acquired disease.

• Small dogs (DMVD): from 6 years old
• Large dogs (DCM/ARVC): from 5 years old
• Cats (HCM): from 6 years old (variable onset)

Planned sedation or anaesthesia 

We recommend screening any patient with abnormal thoracic auscultation (e.g. murmur, arrhythmia, gallop) before procedures. Consider pre-emptive discussion with owners of at-risk breeds undergoing procedures like dentals or imaging, just as you would discuss pre-operative blood tests or blood pressure checks.

Remember: Dogs with early DCM or ARVC in dogs and cats with preclinical HCM may present without a murmur, so consider your ‘at-risk’ patients a little closer.

Concurrent non-cardiac disease

Conditions like hypothyroidism (dogs), hyperthyroidism (cats), or systemic hypertension (both) can cause cardiac changes or worsen existing cardiac disease, making medical management more challenging if left undetected.

Prospective breeding 

Breed schemes exist for some specific breeds in both dogs and cats (details can be found here). Unfortunately, a ‘normal’ heart in earlier breeding ages does not mean acquired disease cannot develop later in life. Screening of patients with notable abnormalities on thoracic auscultation should ideally be screened. However, bear in mind that dogs with early DCM/ARVC or some cats with HCM may not have heart murmurs to rely on.

Familial history

Due to the hereditary nature of many cardiac conditions, dogs and cats with affected relatives or sudden unexplained deaths in the family should be flagged as higher risk.

What Screening Tools Are Available?

Auscultation

• Useful for both congenital and acquired disease
• Only vets or cardiologists on the accredited Breed Scheme panel can sign off official certificates for breed schemes supported by the Veterinary Cardiovascular Society and Kennel Club.

ECG

• Can be a key indicator of cardiac disease in cats with a normal auscultation and those with an abnormal rhythm. 
• Key features in cats:
  • Ventricular arrhythmia is nearly always a sign of underlying myocardial disease (compared to dogs, when systemic disease can cause abnormal rhythms)
  • ST segment changes should raise suspicion for myocardial disease and the possibility of infarction or ischemic change – a very useful prognostic indicator.
• Get a rhythm diagnosis – this can be very informative in both cats and dogs (we can help if you get stuck!)
• Check the rate: extreme high or low rate arrhythmias are more likely to relate to cardiac disease. ‘Slow’ ventricular arrhythmia may indicated abdominal disease. Check our diagnostics page if you aren’t sure. 

Blood Tests – proBNP: elevated where there may be myocardial stretch:

• SNAP test: quick, cost-effective bedside test which will give a ‘normal’ or ‘abnormal’ result. While there are some false negatives, it is still a reliable screening tool which we mostly recommend for cats. Any ‘abnormal’ results should prompt echocardiography. 
• Quantitative analysis: sent to an external lab for a specific proBNP value. This can give more information on the likelihood (or change) of myocardial stretch. It is most useful in dogs to screen for structural changes, particularly when considering DCM in ‘at-risk’ breeds. 

Cardiac Troponin

Not useful as a screen to tell you if there is structural disease, but does give you information if you are looking for evidence of active damage to cardiac myocytes (in active myocarditis or immediately following infarction).

Holter Monitor (24-hour ECG)

• Recommended for patients with suspected of DCM or ARVC 
• Detects intermittent arrhythmias (that may require treatment to reduce the risk of sudden death) that might not be detectable in-clinic, even if there are no significant structural changes

Echocardiography

• The gold standard for diagnosing structural disease
• Supersedes proBNP testing, so if owners are open to echo, go straight to it

Important Reminders

• Some breeds have specific published reference ranges for proBNP – make sure results are interpreted with these in mind. Some breeds have wider ranges than others, so results can be more ambiguous. 
• Cardiac troponin has a short half-life. If it is high, active myocyte damage is likely. If it’s normal, it does not rule out historical damage.
• A negative test doesn’t mean the patient will never get cardiac disease – we suggest annual screening for ‘at-risk’ patients who are not undergoing anaesthesia or assessment for non-cardiac disease. 

How Can HeartVets Support You?

Screening Days

We host regular screening days (auscultation +/- echo) with our Breed Scheme-accredited cardiologists. Get in touch for more information.

Client Handouts

Downloadable information sheets are available on our website – perfect for sharing with clients after consults to consider away from the consult room.

Case Advice

We understand that not everything is as straightforward as the above! For specific case advice, head to our website to get all the answers from one of our cardiologists. 

Contact us for more information and advice