Remy has Cricopharyngeal Disynchrony - which is similiar to Megaesophagus. For a dog to get to be 2 years old, and the owners just begin to think it might be megaesophagus is suspicious.
Remy was eating his meals but not growing as expected, he was not getting the nutrition out of his food. He was very thin and appeared to have a failure to thrive, or chronic muscle wasting. In his case he also had chronic sinus infections. Ultimately he was diagnosed using a barium swallow.
The nature of Remy's disorder is that one muscle of the esophagus pushes the food down, and the other pushes it up. The food ends up coming back out his nose at which point he aspirates it. In the best situation he gets sinus infections, the worst case pneumonia and beyond.
Management of his condition is fairly easy. He eats from a very elevated bowl. Gravity helps the food get to where it needs to be. I also keep him on a regimen of week on/week off of antibiotics in an attempt to avoid an infection. The downside is that his nose is ALWAYS running and he sneezes all over my house. Hey he is more than worth it!
My limited understanding of megaesophagus is that it is often (but not always) manageable. I have seen people who build interesting contraptions for their dog to sit in for 10 minutes after eating to ensure that the food goes down to the tummy. I believe there is also a theory that in some cases an elevated bowl helps.