My folks arent as old as yours but genetics came into play and my mum fell victim to heart disease a couple of years back - her side of the family has a long history of cardio problems. She since had bypass and various other scares - fainting in the toilet when no one was home, shortness of breath etc - before I packed up and left the country as well as when I was here. To make things worse, she is a 13-14 hours flight away whilst I am gathering from your post that your folks arent as far away. Believe me, the number of times I've been frustrated because no one in the family told me about the smaller incidents till days later, has got me thinking that I should just pack up, and go home to be closer 'in case anything else happens'.

But..you never know what the future will hold. People grow old and health problems surface. Its the circle of life. Uprooting what you've built here just to go back because your parents are getting older is, like what Longbyt pointed out, rather shortsighted. Its not about shriking responsibilties towards your parents and I am sure, as parents, they will totally understand that you have a life here and wouldnt want you to give it up to be closer to them just because they are getting older. They want you to be happy and successful if it means going to another country to do it (my mum has to take credit for those words). Life throws us curveballs and you can only grab it by the balls and deal with it when it happens.

Just my 2 rappens worth.