Scanning the athletic patient

‘Athlete’s heart’ can be very difficult to distinguish from a pathological condition like early stage dilated cardiomyopathy on a POCUS-style heart scan. This is because, in an athletic dog, the left ventricle and left atrium will look larger than expected, and systolic function will appear to be lower than normal. Telling apart an adaptation to exercise vs a pathological condition on a point-of-care scan is a very tough call to make.

The case of a young farm dog

A young Border Collie saw a local veterinarian due to rapid weight loss. She performed a detailed abdominal ultrasound examination, but could not find anything sinister. No evidence of a foreign body could be found, either.

The veterinarian did a POCUS heart scan, and noted that the heart looked large and impaired. When she relayed this to the owners to get permission for further investigation, they asked for the dog to be put to sleep – they just could not afford any more investigations, and particularly not to have a heart condition in a working farm dog.

The veterinarian was very nervous to put such a young dog to sleep on the basis of a screening-style heart scan, so ownership of the dog was signed over to the veterinary clinic and the vet asked me to take a look at her in my lab, as a charity case. If her heart condition was not too serious, perhaps she could be re-homed.

Assessing systolic function

There are many (overly)complex ways of assessing left ventricular systolic function, and the ‘gold standard’ for a case like this would be to look at global longitudinal strain (GLS). Even before this, though, there is a lot of information available from just the 2D image and conventional Dopplers. What clues can you pick up from the video below?

You might have noticed:

• There is no mitral regurgitation. Although this is neither sensitive nor specific to LV impairment, nonetheless, some degree of functional mitral regurgitation is extremely common in dogs whose closing forces have been disrupted, or with pathologically dilated chambers. Its absence is one piece of evidence that this dog might not have DCM.
• Looking at the aortic traces, stroke volume is normal. In a dog with an impaired left ventricle, I would not expect such a healthy forward flow out of the left ventricle.
• The right ventricle looks normal. Some degree of RV dilatation and impairment frequently accompanies left-sided systolic dysfunction.

Here are a few more clues:

Hopefully, from the mitral inflow, tissue Doppler (TDI) and pulmonary vein Doppler traces, you also agree that diastolic function appears normal. This is almost impossible in a dog with impaired systolic function. Incidentally, the systolic velocities of her myocardium on TDI look good, too.

Thankfully, what we have is not a dog with dilated cardiomyopathy, but a young, fit, working farm dog with an athletic heart. The veterinarian was absolutely correct that systolic function looked low (it does), and that, in the context of her being unwell, this dog warranted further investigation. Her decision to ensure this happened, no matter what, saved this dog’s life.

Happy ending

The referring veterinarian reviewed the echo report and concluded that this dog’s heart was healthy enough that she could safely return to her home and work. Ownership was signed back over to the farmers, and this little Border Collie is now back on her farm in Kent.

Together, we’ll keep an eye on her with annual echocardiograms.

Further learning

If you are confused by any of the images show in this case, or anything else in echocardiography, you can book a call with me or check out the Confidence in Echocardiography programme. This isn’t ‘just a course’ – it includes permanent membership of our growing community, as well as lifelong access to new training videos and materials as they are produced, keeping you are the forefront of best practice and in touch with the latest guidelines. As the programme grows and the cost of entry increases, it won’t affect you; once you’re in, you’re in!