I've found over the years that to ease the heart beating problem I just needed to concentrate on my breathing. The fast beating will occur sometimes out of nowhere is quite frankly pretty scary. What I do is take a big inhaled breath through my mouth then release the air back out very slowly. While doing this, try to focus on what the heart is doing. The change in oxygen seems to be enough to get my heart back to its normal rhythm. It may take a few big breaths to accomplish this, but it definitely works. I have been using this method for many years. I hope this helps.