Heart muscles don't have Pain sensors and when/if they lack oxygen the Pain shows in various other Places. Usually the Upper body back and left arm. Oxygen deprivation by low or no blood flow in the Arteries of the heart kills heart Muscle tissue often resulting in abnormal turbulent blood flow which can cause a clot forming situation to exist, subsequently. Ultra sound will pick this up. The most likely time to bring this on will be when you are exerting yourself a bit more than what you normally do or stressed Mentally or suffering some other illness. Pilots flying in very stressful situations have recorded Heart rates in excess of 200 BPM. Nev