“In ancient times cats were worshipped as gods; they have not forgotten this.” 
–Terry Pratchett

Adjust and Customize the Diagnostic Plan as Needed: Balance Patient Safety, Image Quality, and the Need for More Information

Since cats often hide symptoms of illness until disease has progressed, your feline cardiac patients may arrive dyspneic and distressed—which may limit your ability to take a full radiographic study. Ideally, at least three views of the thorax are recommended when evaluating the heart and lungs. But for the initial visit, maybe you can only take a DV shot without risking patient safety, since restraint and stress can lead to death in a cat who’s already having difficulty breathing. Using your clinical judgment, you can decide whether to take all radiographs now, or wait until the patient receives initial treatment so they are more stable. If/when a patient is healthy enough, consider sedation to reduce squirming and twisting, too. This will reduce patient movement and positioning without proper alignment—two things that can complicate x-ray image interpretation.

Evaluate Heart Shape to Look for Cardiac Disease

This may be best appreciated on a VD view. Whereas the normal feline cardiac silhouette is shaped a lot like a football, common feline heart conditions may result in enlargement of the cranial portion of the heart, where the atria are located. This results in widening of the cranial portion of the heart. If severe, it may even take on a “Valentine” shaped heart appearance.

To Detect Early Changes and Look for Blood Clots, Add an Echocardiogram

While the Valentine heart shape described above is an important change to look for, this visible change might not occur until heart disease is severe. 

A large part of the reason for this is that, unlike dogs who commonly get dilated cardiomyopathy, felines are more prone to hypertrophic cardiomyopathy. This means enlargement of the heart muscles and smaller heart chambers, rather than a large, dilated heart. Thankfully, echocardiogram can help to find these changes before they appear on radiographs. Additionally, an ultrasound evaluation of the heart can help to find blood clots in the left atrium and evaluate a cat’s risk for a saddle thrombus. For all these reasons, an ultrasound study is an excellent addition to your radiographic studies of the feline heart.

Become Familiar With Age-Related Changes to the Feline Heart, to Avoid False Positives or Misinterpretations

As cats get older, their hearts may look different on radiographs. For example, the cardiac silhouette may lie in a more horizontal (sternal) orientation, which may look like right-sided heart failure when in reality it’s completely normal. Also, they aorta may appear more pronounced and look like a bulge at the cranial aspect of the heart, which may be easy to confuse with true enlargement of one of the heart chambers. By recognizing and expecting these normal changes—and interpreting them in light of the patient’s history and clinical signs—it will be simpler to tell what’s a normal change and what is a true pathology.

Get an Expert Second Opinion for Peace of Mind

Even specialists say that radiographic interpretation of the feline heart can be tricky. So whether you’re a new practitioner or an experienced veterinarian, it helps to use all the resources you have at your disposal. Specialist consults are a great way to offer your patients excellent medical care and provide your clients with a great customer service experience. Clients are used to radiologists interpreting their own x-rays when they go to the hospital, so they often appreciate this same service being offered to their pets. And it never hurts to get a second set of eyes (from a radiology specialist) for peace of mind, especially on tough to interpret cases.


By adapting the diagnostic plan to each patient’s needs, looking at heart shape, adding an echocardiogram, becoming familiar with age-related changes, and obtaining an expert second opinion, it will be easier to diagnose and treat feline patients with suspected cardiac disease. Veterinarians may find it helpful to use all these tools, for the ability to provide more answers and recommendations to worried clients, and for excellent patient care.

Editors Note:

No matter what a veterinarian’s experience level or degree of confidence interpreting radiographs may be, expert teleradiology consults provide a valuable service! Get peace of mind on your radiographic interpretations, with affordable, rapid results. Learn more, here. Whether you love dogs or cats—or both—many pet owners would argue that cats can be more independent and aloof than dogs. And that holds true when it comes to interpretation of feline cardiac radiographs, which can be trickier to interpret than their canine counterparts. For effective evaluation of the feline heart on radiographs, customize the diagnostic plan for each patient, look at heart shape, add an echocardiogram, become familiar with age-related changes, and seek an expert second opinion for peace of mind.

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