Friday, October 3, 2014

Practice EKG Strips 334

Identify the following rhythms.


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


a. Sinus arrhythmia
b. NSR with PACs
c. Wandering atrial pacemaker
d. Atrial fibrillation

a. Atrial flutter
b. Atrial paced
c. Atrial fibrillation
d. Atrial tachycardia


a. Atrial paced
b. Biventricular paced
c. Dual paced
d. Ventricular paced


a. Idioventricular rhythm
b. Complete heart block
c. Sinus bradycardia
d. Atrial fib with slow ventricular response


1. c. Second degree block type II. The PR interval on the conducted P waves are consistent, .16 seconds. If you measure out the P - P interval you will see that what looks like a T wave is actually a P wave. So you have a 3:1 block
2. d. Atrial fibrillation.  This is a difficult strip!. It is irregular and fast. So it is not B because the rate is over 100. It can't be C because the rate is over 100. Remember the rate on WAP is below 100 and the rate on MAT is over 100. For it to be sinus arrhythmia, all the P waves would have to be uniform. There are some flutter waves present but they are not really consistent from beat to beat, even when the rate tends to slow down. Look for example between the 7th and 8th complexes, 10th and 11th complexes, 15th and 16th complexes. So most cardiologist would probably call this an atrial fibrillation (with RVR).
3. Atrial flutter. Compare this strip to the atrial fibrillation strip that I posted. In this strip, the flutter waves are easier to distinguish and are uniform when the rate tends to slow down
4. c. Dual paced. The 7th complex in lead II is dual paced. But if you look closely at the V1 lead, you can see some small atrial paced spikes that for some reason are not picked up by the monitor. (You may have to click on the image to open it up in a bigger window). I don't know why they are not detected by the monitor perhaps it has to do with something in the sensitivity settings of the monitor.
5. b. Complete heart block


  1. Thank you for the practice test. Question, if the QRS is greater or equal to .12 do you call it BBB right away even if they are afib or paced?Thank you

    1. I generally do not call a widened QRS a BBB when interpreting strips in a clinical setting. It could be considered making a diagnosis. However, outside of the clinical area, I would want to look at the widened QRS complexes in a couple of other leads. If you have a monophasic R wave in either lead I or V5 or V6 or a negative QRS in V1 then it would suggest a LBBB. If you have an RSR complex in V1 then it suggests a RBBB. Sometimes the conductions system is very messed up and it may not have the characteristics of either a RBBB or LBBB in which case it would be called a non-specific conduction delay. So, it safer just to call it atrial fib with a wide QRS complex. With ventricular paced rhythms, the QRS complexes will be widened because the conduction lies outside the normal conduction system. The lead generally lies in the lower right ventricle so the QRS complex looks like a LBBB in lead V1. In the strip above the slurring of the S wave in lead II is sometimes seen with a RBBB suggests a delay in the activation of the right side of the heart but we would need to actually see lead V1 to make a more definitive interpretation. I hope this helps.