I know heart palpitations are "normal" in pregnancy. Aa friend of mine had to wear a monitor where she had to push a button every time it happened so they could keep track of how often it was going on. Turned out to be fine. But it couldn't hurt to ask your healthcare provider about it. :)
Before I could possibly have known I was pregnant--as in *maybe* 2 days after ovulating--I started having palpitations to the point that I was very close to going to an urgent care center. I started a calcium/magnesium supplement after reading that they can be related to low blood calcium & I did feel a little better. A nurse practitioner friend of mine told me, though, that even if your dietary calcium intake is pretty much zero, your body will leach calcium from your bones, so your blood calcium won't be low unless you have a parathyroid issue. Since I have some strange "regular" thyroid swelling that no one seems to be able to explain, I was kind of freaking out that I had some sort of chronic malady. About a week or so later, I figured out I was pregnant. Once I informed that friend, she was like "DUH" but since she'd also struggled TTC'ing for a long time, her brain didn't make that presumptive leap that others would have.
So yeah, it's normal. But if you're not getting enough calcium, it may help & is generally a good idea, anyway. :P (oh, and calcium citrate is more absorbable than calcium carbonate/Tums. I take those, too, but not for the calcium.)