Heartbeat (probably flame worthy)

lauren.cus

Okay I know this came up on a post before and the OP was flamed for it, so I'm going out on a limb here. The last u/s I had was at 7 weeks and it wasn't that clear. The past few times I've been listening to the Doppler I've been hearing my heartbeat (70ishbpm), a heartbeat on one side (170bpm) and a hb on the other side (160 bpm). Could this be an echo from the baby's heartbeat even though they're different bpm? I know the placenta can sound like a hb but is it that fast and I thought it sounded more like a swooshing not a hb. Any thoughts?