I have read that many people are experiencing the fluttering under the left breast. It could also be described as a vibration if my cell phone was in my lewft pocket. It is not painful, but is concerning because it happens a lot....almost continually. I have AFib and am on xarelto and also am on diovan and metroprolol for HBP. Could anyone comment or tell me if this could me serious. I am about to get on a flight, and am now wondering if I should.