Hi, and welcome, and I'm SO sorry about your experience! Was that your first bowel obstruction, and do you know what caused it? I assume that it was partial if they didn't operate on it, but given what happened with your heart I'm sure the situation was very complicated (and scary!).
I've had 30+ partial obstructions in my life. This is NOT meant as medical advice, because I know the tube can be very helpful and perhaps life-saving sometimes, but I've always refused them because I've heard how awful the insertion is, and so far I've been lucky because my obstructions usually resolve on their own in about 12-24 hours (but they are horribly painful!).
I now mostly live on very healthy smoothies, soups, juices, and easy-to-digest foods--just in case. I know that if/when I have an obstruction, that will make the whole episode much easier to deal with.
Talk to your Gastro doctor, but don't expect him to have any real solutions. Generally they will just tell you to get to the ER (and they should) if you start getting another one, but no one seems to know how to prevent them.
Read through the posts on this thread about diet strategies, etc., that we've all tried.
I wish you all the best!