Sudden feline death can occur in cats for a number of reasons, including cardiomyopathy. Find out more about what sudden feline death is.
Unfortunately sudden death can occur in cats for a number of reasons, and the most common is cardiomyopathy (or heart disease). As a feline vet I am constantly telling my owners how cats are 'masters of disguise' and rarely show any signs of disease until, often, it is too late.
Heart disease is particularly difficult for an owner to detect in a cat as often the only indication is that they may sleep more - and when cats sleep for 18 hours a day, that's easy to miss! Regular visits to the vet may detect early warning signs but even vet surgeons may not always detect heart disease - heart murmurs can be intermittent and affected by other conditions such as stress or increased temperature and so may not even be associated with heart disease.
The only way of confirming cardiomyopathy is to have specialised diagnostic tests such as an ultrasound of the heart (an echocardiogram), which would confirm structural changes, and possibly an ECG if there were an arrhythmia. However, in early diagnosis of cardiomyopathy there is still debate amongst veterinary cardiologists about when and if to initiate treatment for these cats and regardless of whether they are on treatment, sadly the risk of sudden death from cardiac arrest is still high.
However, heart disease may not have been the cause of death. Poisoning and other systemic conditions (such as Feline infectious peritonitis) are other potential causes for insidious illness leading to death, and again are sometimes difficult to detect due to the secretive nature of the cat. Ultimately, as upsetting as this is for you, you have to try and take comfort from the fact that Freddie was enjoying a happy and fulfilling life and would have known little about his last few moments.
Advice given by vet Nikki Gaut.