Distinguishing heart failure in dyspnoeic cats

Managing a dyspnoeic cat in practice can be stressful for everyone – not to mention your feline patient! Deciding what to do (and when) without making things worse is a genuine clinical challenge. Fortunately, help is at hand in the form of a practical, first-opinion-friendly triage tool: the RAPID CAT algorithm. Don’t forget, if you need support with your cardiac patient, head to our website for case advice.

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Developed from real-world data in general practice, RAPID CAT is a useful screening tool that can guide urgent stabilisation and streamline your diagnostic pathway with minimal invasiveness, which is key when time and tolerance are short.

In dyspnoeic cats, fast decisions can be life-saving, but it’s easy to hesitate. This clear, practical framework can be used to support initial case management – especially when echocardiography or specialist input isn’t immediately available. And crucially, it’s built around clinical signs you already assess during every physical exam.

What is RAPID CAT?

RAPID CAT was a prospective observational study led by one of our RCVS Recognised Specialists Dave Dickson (Dickson, D., Little, C. J. L., Harris, J., & Rishniw, M. (2018). Rapid assessment with physical examination in dyspnoeic cats: the RAPID CAT study. The Journal of small animal practice, 59 (2), 75–84) involving 90 cats presenting with dyspnoea to first-opinion practice. The aim was to identify physical exam findings that could help differentiate cardiac from non-cardiac causes of dyspnoea at the point of triage – before imaging or bloods.

The following findings were strongly associated with congestive heart failure (CHF):

• Respiratory rate > 80 brpm
• Heart rate > 200 bpm
• Temperature < 37.4ºC
• Gallop sound present

When these clinical findings were used in a diagnostic algorithm, it predicted a cardiac cause for dyspnoea in 80% of cases.

What’s New? RAPID CAT 2

We recently completed the follow-up validation study, which included 185 cats and reaffirmed the utility of the same simple algorithm:

• Respiratory rate > 80 brp
• Heart rate > 200 bpm
• Temperature < 37.5ºC
• Gallop sound present

The accuracy of this combination for identifying CHF as the cause of dyspnoea was 76% – only slightly lower than the previous study but still hugely significant to help differentiate the common differentials. It’s not a diagnostic test, but a screening tool designed to help guide first-line treatment and imaging decisions, not replace definitive diagnosis.

Using the Algorithm in Practice

The RAPID CAT tool offers a calm, evidence-based structure for those high-pressure moments:

If RAPID CAT is positive:

• Consider giving diuretics (e.g. furosemide) as first-line treatment
• Perform thoracic POCUS (point-of-care ultrasound) to look for pericardial effusion, pleural fluid, or left atrial enlargement
• Prioritise stabilisation before attempting thoracic radiography

If RAPID CAT is negative:

• Proceed with thoracic radiography or POCUS to assess for non-cardiac causes (e.g. asthma, effusion, mass)
• Keep cardiac disease on the list if signs persist or evolve – this is a screening aid, not a rule-out

Take-Home Points

• RAPID CAT helps identify cats likely to have cardiac dyspnoea based on physical exam alone
• The key features: gallop sound, tachycardia (>200 bpm), extreme tachypnoea (>80 bpm), low temperature (<37.4–37.5ºC)
• If positive: diuretics and cardiac POCUS are the recommended next steps
• If negative: consider radiography and continue workup for non-cardiac causes
• This is a triage tool, not a diagnosis — use it to guide, not define

Tricky case?

If you’re working up a dyspnoeic cat and not sure which way to go next, we’re happy to help review your findings or advise on further investigation. Whether it’s an urgent case or a second opinion on imaging, we can assist – cats really don’t read the textbook, so we all need guidance at times!

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