Practice EKG Strips 390

Identify the following rhythms.

1.

a. First degree heart block
b. Second degree heart block type I
c. Second degree heart block type II
d. Third degree heart block

2.

a. 1st degree heart block
b. 2nd degree heart block type I
c. 2nd degree heart block type II
d. 3rd degree heart block

3.

a. 1st degree heart block
b. Wenckebach
c. Mobitz II
d. Complete heart block

4.

a. First degree heart block
b. Mobitz I
c. 2nd degree AV block type II
d. Complete heart block

5.

a. 1st degree heart block with a run of VT
b. 2nd degree heart block type I with a run of VT
c. 2nd degree heart block type II with a run of VT
d. 3rd degree heart block with a run of VT



Answers
1. A. First degree block. The rhythm is regular with a rate around 83 bpm. The P waves are upright and paired with a QRS complex. The PR interval is prolonged at .22 sec. The QRS complexes are wide, .12 sec. The QT interval is about .40 seconds. No ectopic beats are seen.

2.  d. 3rd degree heart block.  There is no association or pattern between the P waves and the QRS complexes. In fact on the 2nd, 3rd, and 5th complexes a P wave falls on the T waves. This only happens when there is complete AV dissociation. Now, if this were a type one block then there would be progressive elongation of the PRI over successive beats. When looking at the strip you can see that the PR interval of the 2nd complex is much longer than the PR interval of the 3rd complex. If this were a type II block then all the QRS complexes would be paired with a P wave and the PRI would measure out the same. There would also be some additional non-conducted P waves.

3.  B. Wenckebach pattern.   On the first two complexes there is progressive prolongation of the PR interval over successive beats. This is followed by a dropped beat.   This is followed by a pause and a single beat.  This is not a typical pattern for Wenckebach.  A dropped beat follows the 4th complex.  Then the 2 beat series resumes.

4. C. 2nd degree AV block type II. Two non-conducted P waves are seen at the beginning of the strip. The next three beats are sinus in origin. The PR interval on the couched beats is the same from beat to beat. Two more non-conducted beats finish out the strip. If you were to measure the P - P interval then you would find it to be consistent across the strip

5. A. 1st degree heart block with a run of VT. The underlying rate is around 65 bpm. The P waves are positive and associated with a QRS complex. The PR interval is prolonged at .24 seconds. The QRS complexes are narrow at .08 seconds. The QT interval is around .40 seconds. There is a four beat run of VT.