31.   If it detects an abnormally rapid heartbeat, it sends an electrical surge to a defibrillator coil and jolts the heart back into a normal rhythm.

32.   Tachycardia is an extremely rapid heartbeat.

33.   The injury led to a rapid heartbeat and forced Karpovtsev to sit out the rest of the game.

34.   Watson said they suspect it may have been triggered partly by severe bouts of rapid heartbeat he suffered before the hole in the heart was repaired.