Answer and Explanation 7

7.  B is the correct answer.  This is a second degree AV block type two.  There is a characteristic lengthening of the PR interval greater than 0.20 seconds until the QRS complex is dropped.  Third degree block is complete AV dissociation.  The P waves have equal distance between them as do the QRS complex.  Second degree AV block type II is when there is no lengthening of the PR interval the the QRS complex just drops.