I'm not sure if I mentioned it earlier, but when I went to my pre-surgery nurse's appointment, she took my blood pressure, height, weight, etc.
Then she listened to my heart beat. For ages. "Are you aware you have a heart murmur?" she says. Um, no. That's a new one for me!
So I duly trotted off to see my GP, to get myself checked. My initial Googling confirmed what the doctor told me: it's very minor, relatively common, and I won't need any treatment. In fact, my doc said that the new definition of a normal heart is someone who has not yet needed an electro-cardiogram!
Funny thing was when he tried to replicate the noise my heart was making "luh, sssssdub" I nearly got the giggles. But it was a good explanation!