Hypertrophic cardiomyopathy (HCM) is the commonest form of heart disease in cats and it is very common in Maine Coons.Universities Federation for Animal Welfare
Elisa in her article wrote that Leo died of a saddle thrombus. This is a blood clot at the point where the aorta splits into 2 arteries; hence the use of the word ‘saddle’. The aorta is the largest blood vessel in the cat’s body and blood passes into it from the heart’s left ventricle (see diagram).
About 30% of Maine Coons have a genetic (inherited) predisposition to have hypertrophic heart disease (hypertrophic cardiomyopathy). This causes the walls of the heart to thicken.
This leads to an increased risk of the blockage of major blood vessels by blood clots. A thrombus is a blood clot.
It is the underlying tendency of the Maine Coon to develop this heart disease which resulted in Leo’s premature death.
The heart created the blood clot which travelled to the area of the aorta where is splits and this blocked blood flow.
As I understand it death comes from this condition because at the end the heart stops beating causing cardiac output to fall rapidly and death occurs immediately.
Sources: Various veterinary websites.