No atrial impulses are conducted
P waves normal and regular P-P intervals unrelated to slower regular R-R intervals
QRS narrow if block above bundle of His
QRS wide if block below bundle of His
PR variable
Differentiate from AV dissociation without complete heart block
P waves normal and regular P-P intervals unrelated to slower regular R-R intervals
QRS narrow if block above bundle of His
QRS wide if block below bundle of His
PR variable
Third degree AV block
First degree AV block
Second degree AV block type I 
Wide-complex tachycardia
Second degree AV block type II
Left bundle branch block
Narrow-complex tachycardia
AV dissociation without complete heart block