sudden cat death

Question
We had a 6 year old siamese cat that appeared perfectly healthy when we left the house a 9 o'clock.  We returned at noon, and found the cat dead on the floor.  No bleeding or marks on the body.  This cat had a history of regurgitating his food, and throwing up hair balls (probably because he was always grooming our other siamese cat).  This was an exceptional cat - affectionate, and funny. We are having a hard time dealing with this loss, and would like to know what killed him.  Can cats this age have heart problems?  Is it possible that he tried to regurgitate, and choked.  Is it possible that the 2 cats were running through the house, and he broke his neck.  He got out of the house for a few minuted the day before he died (in Florida).  Is it possible that he was bit by a spider? Any of your thoughts would be greatly appreciated.

Thank you.  Nicholas and Barbara Celia

Answer
My sincerest sympathies for your loss.  Without being able to examine him it is hard to say for certain what happened, however two of the most common reasons for sudden death would be an undetected heart problem and heartworm disease.

Heartworm is passed by mosquitos and may infect your cat without any signs for quite some time.  The first sign can be when a group of the worms breaks off and travels in the bloodstream  to the lungs or heart leading to pulmonary emboli and/or cardiac blockage.

It is doubtful that he could have died from problematic regurgitation of physical trauma, and a spider bite would likely have shown symptoms earlier.  But without being able to examine him I cannot rule out any cause 100.

Again I am very, very sorry for your loss.