Oh no the heart failure cat! What now?

Presenter: Rachel James – MA VetMB CertSAM DVC MRCVS, Nantwich Veterinary Hospital. Member of the Management Board Committee for the Journal of Small Animal Practice; Guest Editor, Journal of Small Animal Practice, Cardiology Supplement; interests include all aspects of cardiorespiratory medicine.

I was relieved to learn that Rachel James who led last week’s webinar agreed that dyspnoeic cats are some of the most difficult cases to manage and diagnose in practice. This is partly due to the fact that these cats have a tendency to die the moment you try and do anything with them, so any advice on how to diagnose these cases as efficiently and as safely as possible is always welcome.

Rachel’s webinar delivered exactly what was needed to achieve this, offering practical tips on how to make a diagnosis with minimal stress for both cat and vet. For example, Rachel believes thoracic radiology is imperative in diagnosing heart failure, but will ideally only perform x-rays in a stable patient. In the unstable patient Rachel advises performing a brief ultrasound examination, initially with the aim of answering a standard set of questions which are as follows:

  1. Has this cat got an enlarged left atrium?
  2. Has it got a pericardial effusion?
  3. Has it got a pleural effusion?
  4. Has it got a thoracic mass?

If the answer to all of these questions is NO, this cat is unlikely to have heart failure, and depending on the state of the animal, the use of steroids may warrant consideration or a thoracic x-ray is indicated once the cat is made as stable as possible. However if the answer is YES to any of these questions then further treatment can be instigated. For example if there is left atrial enlargement, the affected cat should be treated as appropriate for heart failure. If there is pleural effusion, the chest should be drained. Rachel also reminded us that a pericardial effusion in the cat can be an indicator of heart failure and appropriate treatment should be administered.

Rachel explained that emergency treatment for heart failure usually involves draining any pleural effusion, and initiating treatment with frusemide at a dose on 1-2mg/kg followed by a 1mg/kg dose hourly for 2-3 hours. Rachel warns against using doses of frusemide higher than 2 mg/kg as it may cause cats to become further tachycardic and hypotensive. Pimobendan could be considered for use in hypotensive cats, however if loud murmurs are present there may be left ventricular outflow obstruction meaning this drug should be used with caution in these particular patients.

The diagnosis and management of the emergency dyspnoeic cat in heart failure was not the only element discussed within this webinar. A good understanding of the mechanisms causing heart failure in cats is essential, and were also fully discussed by Rachel who included the many forms of feline cardiomyopathy. She also discussed the importance of obtaining a decent history and performing a thorough physical examination. For example, did you know that a third of cats in heart failure present with vomiting, and most murmurs associated with cardiomyopathies will be most easily auscultated just left or right of the sternum?

Diagnostics such as echocardiography, radiography, blood pressure measurement and the dreaded ECG were also discussed. Apparently left anterior fascicular block seen on an ECG is a very common finding in cats suffering cardiomyopathies and Rachel explained in simple terms that a left anterior fascicular block looks like an ‘upside down’ ECG reading.

Rachel included a number of videos of echoes, ECG examples and heart sound recordings which were invaluable and made this webinar an excellent all round discussion on one of the hardest conditions to diagnose in practice, and for this reason should not be missed.

The Stethoscope (MRCVS)

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