Second-Degree Block (Type I)
Second-Degree Block (Type I)
Regular; P to P is regular, 60 to 100 bpm
R to R intervals tend or decrease progressively; until QRS is dropped. rate is variable
More P waves than QRS complexes
Unchanged unless aberrant conduction due to premature beat or increased rate, but dropped in a cyclic pattern
PR: increase with each beat
QRS: <0.12 sec