Hi @drumsace, you ask a very good question, and I believe you answered it yourself!
I do not know if your cardiologist is an expert in HCM or HOCM, however, if you feel like getting a second opinion, you should listen to your inner voice. I was misdiagnosed by my own cardiologist four times with four different heart conditions. It took getting a second, followed by a third opinion to be correctly diagnosed with Hypertrophic Cardiomyopathy, and not only that it was obstructed. If I had not listened to my inner voice, I have no idea what may have happened.
It's not uncommon that HCM is missed. I would encourage you to listen to yourself and look for another set of eyes to take a look at your echo. This way you will have more information and that is never a bad thing! Being your own advocate is the most important thing you can do for yourself. Are you near a Center of Excellence (COE)? These are spread throughout the country, with Mayo being one of them and Mayo is a COE for all things hypertrophic cardiomyopathy. Do your research, learn as much as you can, and then being informed make the best decision for your own healthcare. Are you able to find another cardiologist nearby that specializes in HCM?