A pause in the cardiac rhythm due to momentary failure of the sinus node to initiate an impulse. This will result in at least one (1) "dropped beat". The pause between normal conducted beats should be at least twice the immediately preceding P-P interval. A differentiating factor between whether it is called Sinus Pause or Sinus Arrest is that in Sinus Pause, the pause is a multiple of the preceding R-R intervals; and in Sinus Arrest the pause is not a multiple of the preceding R-R intervals. The severest form of sinus arrest (the absence of 4 or more beats) is called Asystole.