Aortic stenosis is a heart condition that rabbits are typically born with (congenital). It occurs when the aortic valve, which controls blood flow from the heart to the rest of the body, is narrower than normal. This narrowing makes it harder for the heart to pump blood effectively throughout your rabbit's body.

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Some rabbits with aortic stenosis may show no signs at all, which can make this condition challenging to detect. However, other rabbits might display several concerning symptoms. You may notice your rabbit fainting (syncope) or seeming unusually tired and lacking energy (lethargy) or showing general weakness, including falling asleep whilst eating or being “wobbly” when exercising. Some rabbits with this condition don't grow as large as they should. Your rabbit's gums should be pale pink, if you notice they are very pale or if they are blue then it is a sign to contact your veterinarian urgently. In severe cases, this condition can lead to sudden death, which is why regular veterinary check-ups are important, even for rabbits that appear healthy. Your veterinarian may be able to hear a heart abnormality with their stethoscope at a normal check-up and therefore detect the condition early, before symptoms develop.

When a veterinarian suspects aortic stenosis, they will typically use two diagnostic tools. The first is radiography (x-rays), which helps them see the overall size and shape of your rabbit's heart. The second tool is cardiac ultrasound, which uses ultrasound technology to create detailed images of the heart while it's beating. An ultrasound scan is a common and painless procedure that involves placing an ultrasound probe on the skin. The probe is covered in hypoallergenic gel which allows waves to travel from the probe into the body to create a real time grey, black and white image on a screen. The procedure is relatively low risk, however with rabbits that have a heart condition, stress can have fatal consequences and therefore all efforts should be made to reduce the stress involved. This may include you needing to provide details of their usual routine and how often they are handled. The ultrasound scan allows veterinarians to see how well the heart is functioning and measure the severity of the valve narrowing.

Treatment options for rabbits with aortic stenosis are currently limited. Veterinarians can provide palliative medical treatment, which means giving medications to help manage symptoms and make your rabbit more comfortable. While other animal species have benefited from surgical procedures and specialized balloon treatments (called valvuloplasty) to open up the narrowed valve, these procedures haven't been documented in rabbits yet.

The outlook for rabbits with aortic stenosis varies significantly depending on how severe the narrowing is. Rabbits that don't show any symptoms (asymptomatic) generally have a good chance of living a normal life. However, rabbits that show symptoms and have severe narrowing of the valve typically have a more challenging road ahead with a less favorable outlook. If your rabbit has aortic stenosis, it is important that they do not breed. The condition can be passed down to their kits and if they are female (a doe), then it is unlikely they will survive pregnancy and birth due to the extra pressure this will put on their heart.

Contact your veterinarian immediately if your rabbit shows any of these signs:

• Reduced exercise, this includes showing unusual tiredness or reluctance to move.
• Fainting or collapsing.
• Not growing as expected.
• Having difficulty breathing.
• Showing any changes in behavior or energy levels.
• Reduced appetite or stops eating.

Rabbits become stressed easily. Management of stress and pain is just as important as managing their health condition. Stasis/ileus (when the digestive system slows down and can stop entirely) is a serious condition in rabbits, and should be treated as an emergency, so if your rabbit stops eating before or after their diagnosis and treatment, contact your veterinary surgeon immediately.