Tip #5 Keep it simple when auscultating the heart

If you do not know what all the differentials for a pansystolic or holosystolic or crescendo-decrescendo murmur are, don’t worry. This stuff is not important in my opinion in the early stages of your career. Those nuances can develop later.

Focus on the big questions:

• Can I hear the heart?
  • Yes – great.
  • No or the heartbeat sounds dulled – is there something in the way like a pleural or pericardial effusion, a mass, or the chest wall of an extremely obese patient?
• What is the heart rate?
• If there is a murmur:
  • Is it systolic, diastolic or continuous?
  • Is it loudest on the left or the right?
  • Is it loudest at the base or the apex?
  • Is it soft, moderate or loud? If possible, grade the murmur on the 1-6 scale, but this is not essential.
• Are there any diastolic gallop sounds?
• Is the heart beat regular, irregular (chaotic beats or tripping in the rhythm), or regularly irregular (i.e. likely respiratory sinus arrhythmia)?
• Is there a femoral pulse for every heartbeat?

With a full cardio-respiratory examination including a thorough auscultation, you can go a long way toward narrowing down your differential list and deciding on what diagnostic steps might be required. Try to do a full cardiac exam in every patient if you can – we need to calibrate what ‘normal’ looks, feels and sounds like in our minds. This way, the abnormalities will become more obvious in contrast and you will learn to trust your ears when something does not sound right.

Tip #6 Look for Sinus Arrhythmia in your physical exam

If the dog has a respiratory sinus arrhythmia (i.e. heart rate increases during inspiration and then decreases during expiration in a cyclical fashion), it highly unlikely to have congestive heart failure. A respiratory sinus arrhythmia can be a normal clinical finding in dogs and signifies normal or high vagal tone.

Alterations in both sympathetic and parasympathetic tone associated with advancing cardiac disease lead to loss of a respiratory sinus arrhythmia, hence the predominant underlying rhythm usually observed in patients with congestive heart failure is sinus rhythm (i.e. regular R-R intervals that do not change with respiration), although arrhythmias such as atrial fibrillation or ventricular premature complexes may also be noted in these cases depending on the underlying pathology.

In contrast, a sinus arrhythmia is an abnormal finding in a cat in an in-clinic environment.

Tip #7 Cats are not small dogs

Cats are not small dogs when it comes to cardiology – be aware of the various species differences in both the normal findings and disease processes.

Tip #8 Take good quality radiographs, but be realistic about what can be achieved in each case.

• Try to get good inspiratory views if xray is indicated – this will make assessment for oedema and cardiomegaly much easier. Obtain right lateral and dorso-ventral views for chests (but remember to take the DV first to avoid atelectasis).
• If judged safe and possible in the case, lightly sedate the patient if you can. The resulting images will be of superior diagnostic quality and this is best practice under ALARA principles.
• Put a wedge under the sternum and draw the forelimbs well forward. – it can make a big difference to the quality of your lateral view.
• If your patient is dyspnoeic and won’t tolerate being in lateral for xrays, then don’t push it – a perfect right lateral xray is not worth causing patient deterioration for. In these cases, consider an alternative diagnostic modality, for example lung ultrasound to assess for the presence of numerous B lines etc.

Do your best to get images of diagnostic quality, but be pragmatic about what is possible in each particular situation. For cats that are too stressed to be handled for xrays, put them in a metal wire cat carrier, with the plate inside the carrier under the cat. Take your xray in this manner with the cat just sitting on the plate, with the lid of the carrier left open. These views will be far from perfect, but are a good initial step for basic assessment of the chest for pulmonary oedema or pleural effusion without causing your patient to get stressed and further decompensate.

Severly compromised dyspnoic patiens need careful handling during diagnostic investigations to avoid further deterioration. In cats, initial radiography may be achieved by allowing the patient to sit on top of the radiographic plate whilst placed inside a wire cage. The exposure is taken in this way with the lid of the cage remaining open, and the patient minimally stressed.

Tip #9 Don’t be afraid to take a hands-off approach with dyspnoeic cardiac emergency cases.

Perform a basic triage examination, give them oxygen, careful sedation, any medication you feel is essential to improve the situation and then give them space to relax. Watch them and then proceed carefully once they have calmed down a little. This is especially important with cats, as they can easily be pushed over the edge in these situations.

For yourself, panic on your part in these cases is also futile – cardiac emergencies can be stressful to begin with, but you still need to be able to think clearly and proceed calmly. Try to take a breath and remain calm, take things slowly with the patient and remember that providing oxygen is never a wrong first step.

Tip #10 Don’t be afraid to ask for help

You don’t need to have all the answers with cardiac cases as a new grad. All you need to recognise is that ‘something is not right with this heart’. Give yourself time to think logically and formulate an initial diagnostic plan based on your physical exam. This may include asking for help or an opinion from a more experienced vet in your practice or advice from your local cardiologist. Referral for additional work-up may be indicated in many cases in order to make a firm diagnosis and to optimise the treatment plan, as many cardiac diseases require additional modalities including echocardiography or ECG/holter monitoring for a firm diagnosis.