dear smedley's mom,
i'm so, so very sorry to read about your loss. i'm still reeling from losing madelynne, the most cursingly tragic and traumatic loss to date (and i deal with much, much loss), and am on this site now many times a day. every loss is different, and for this one i need nearly constant support. my grief journey has taken on epic proportions...
i'm reading many posts. the kinship of the loss of a furred or feathered child on this site has greatly helped to ease my burdens. and so i landed on your story. i nearly held my breath until i read your post about the results that showed heart failure. as soon as i read your first entry, i said to myself: heart failure and there is no way she would have known. i did not read much past your post of this news, as i felt then compelled to write you if for no other reason than to assure you you didn't miss anything and even had you known, there is very little you could have done to prolong his life. your peep was asymptomatic. the reverse snorkeling noises you describe are not cause for racing to the vet. over the last years, i have found out that this is not a rare occurrence, the sudden, unexplained death in cats. having traveled in animal rescue circles for many years, one rescuer started having autopsies performed, esp. for unexplained, unexpected deaths, where nothing remarkable was present. heart failure was at the root cause of most of these. this rescuer has rescued 100s and 100s of cats over the years.
my sweet mackenzie, the reason i started here last july, died of "unknown causes." my vet performed a necropsy and the only thing she could find was that the upper chambers of mackenzie's heart were very small on the inside, i.e., thickened walls. the stress of the surgery no doubt taxed her heart terribly and she could not fully recover, dying in my arms within minutes of bringing her home. none of the extensive presurgical tests indicated there was any issue with her heart. an xray showed a normal heart. had i had an mri done, it would have shown this heart defect she lived with her entire life. but, an mri was not part of the protocol, nor was it indicated since exam and xray showed her heart to be fine. she managed this very well and hid this ailment perfectly. her lifestyle was very calm and sedentary and exclusively indoors. once she passed the wild times of kittenhood, she enjoyed her days slumbering, eating, and finding me for attention. she was only 12 when she died. my vet explained to me that cats dying "unexpectedly," is not uncommon, even very young ones, like during spay surgeries. no one would think a very young peep, 6 months or younger, would die of heart failure. but this happens more than we realize. my vet always does a full exam before any procedure involving anesthesia, and any other tests that are warranted.
this blog by christine kane may be of comfort to you:
http://christinekane.com/on-losing-a-beloved-pet/. this one as well,
http://www.tickld.com/x/old-man-explains-d...eving-young-man.
again, i'm so very, very sorry for your loss.