Go see a specialist, TS.

When I was a little bit younger, I craved adventure and got it into my head to try to join the french foreign legion. I was healthy and supremely fit, but before I left for france, I got myself checked out at a heart specialist in KL. Got an ultrasound of my heart and the doc said it was bigger than normal size. I got alarmed and asked him why so? Was it a disease or abnormality? He smiled and said I had the heart of an athlete and it was functioning fine. Phew! He then turned the monitor to me and i saw my own heart beating on the screen...no blockages, valves working as they should, all ok. It was hella cool to see that.

I believe the test is called an echocardiogram.