Heart problems

Heart (cardiac) disease in guinea pigs has been documented for years and are known to be predisposed to developing heart issues, especially later in life. It is not fully known why guinea pigs develop heart issues but there is thought to be some genetic factor involved (for example if one guinea pig develops problems then her siblings or young are more at risk) as well as older age becoming a factor.

Guinea pigs are predisposed to two main heart problems, dilated cardiomyopathy (DCM) and pericardial effusion.

DCM is where the muscles of the heart become lax and floppy and become less effective at pushing the blood around the body.

Pericardial effusion is where blood or fluid builds up in the sac which surrounds the heart, it is usually caused by a tumour of the heart.

Many guinea pigs will not show any signs of heart problems early on in the disease process and it is not until they hit a crisis and their heart begins to fail that they begin to show symptoms. Symptoms of potential heart problems in the early stages may include:

• Decreased appetite
• Increased respiratory rate
• Weakness, reluctance to exercise or falling over
• A swollen abdomen (this is due to fluid in the abdominal cavity)

In the later more severe stages where the heart is beginning to fail fluid often builds up in your guinea pigs lungs, if this is the case you are likely to see:

• Open mouth breathing and increase respiratory rate and effort (due to fluid on the lungs)
• Blue tinged or white gums and/or tongue
• A heart murmur may be heard when your vet listens to your guinea pigs heart with a stethoscope
• Collapsing and weakness

If you see any of these symptoms your need to get your guinea pig to a vet immediately, a guinea pig in heart failure is an emergency and if your vet is not open you will need to contact your out of hours vet.

Your vet will give your guinea pig a thorough examination, in some cases your vet may hear a heart murmur (an unnatural sound caused by blood flowing incorrectly in the heart). This is not always the case and they are often very difficult to detect as guinea pigs hearts are very fast.

The only way to confirm diagnosis of heart disease is to ultrasound the heart. Your vet will be able to do this conscious or with a very light sedative if your guinea pig is a little wriggly. They can then take measurements of the heart to confirm if your guinea pigs heart is abnormal. If your guinea pig looks like they are in heart failure your vet is likely to place an ultrasound on their chest to check for fluid build up to confirm diagnosis before commencing emergency treatment.

Sadly heart disease carries a very guarded to poor prognosis in many cases, this is because they are often picked up in much later stages of the disease process. If your guinea pig is suffering from a pericardial effusion, sadly, this carries a very grave prognosis and often your vet will advise that it is kinder to put your guinea pig to sleep. If your guinea pig is suffering from dilated cardio-myopathy then there are some treatment options available.

If your guinea pig is currently in a crisis of heart failure then intensive treatment will be needed to correct this first, your guinea pig will need to stay in hospital for this. Initial emergency treatment for this will include:

• Oxygen
• Diuretics to help remove any fluid build-up
• Pain relief
• In some cases your vet will want to manually remove any fluid in the chest by placing a small needle between the ribs, your guinea pig will need to be sedated for this and it does carry risk

If your guinea pig is stable and not in any degree of respiratory distress or has been successfully stabilised following a heart failure crisis then you may be able to start on a number of different drugs to help keep the symptoms of heart disease at bay. These will need to be carried on for the rest of your pet’s life. Your vet will discuss with you which medications will be best to use and when. The main ones used are:

• Diuretics to help remove any fluid build-up on the chest
• Pimobendan – this makes the heart contract more effectively
• Enalapril – this drug helps reduce the stress placed on the heart via the pressure in the blood vessels

It is important to remember that none of these medications are licensed for use in guinea pigs, but can be used under the cascade system. Your vet may ask that you sign a consent form to say you understand that the medications are being used in this way.

Sadly, as there is very little research into why guinea pigs get heart disease there is no way of stopping your guinea pig from developing problems.

The key to any heart problems is to detect them early on in the process. Ensure that you know your guinea pigs usual routines and personality and if you are concerned about their health have them examined by your vet.