Yeah I have this sometimes as well. It’s actually improved a lot with treatment & diet ( yeah !!!!!
I used to have it a lot , and it was very noticeable when laying in bed. Eaither that or I usually would be laying down when I had it , as those were times I was feeling VERY bad & spending most of my time in bed.
It often came with other symptoms for me. Like headaches, pressure, passing out ( or feeling like it) , dizziness, tinnitus, nausea, hot or cold sensations and others....so those symptoms would cause me to lay down - and then the whole body beating would become really obvious!