First Degree Block
Regularity: R-R intervals are regular, overall rhythm is regular.
Rate: The rate depends on the underlying rhythm.
P WAVE: There is one p wave in front of every QRS. The P waves appear uniform.
PRI: Measures more than 0.20 seconds in duration. PRI is consistent.
QRS: Measures less than 0.12 seconds.
*Remember that with a first degree block, you still have to identify the underlying rhythm. A block is additional finding within a rhythm*
