May 2011 ROM - April Contest Discussion

This is the criteria given

for April’s rhythm contest.

Atria: Rate is 100 bpm

Rhythm is regular

Ventricles: Rate is 50 bpm

Rhythm is regular

QRS Complex: 0.18 seconds

PRI: 0.16 seconds - constant

As you can see by the atrial and ventricular rates, the

atrial rate is twice as fast as the ventricular rate. Both

rhythms are regular. Because there are twice as many P waves as there

are QRS complexes, there is a block resulting in a 2:1 AV conduction ratio.

The QRS complex is wide since it measures 0.18 seconds.

Because we don’t know the reason for the abnormal width

of the QRS complex, that is all we can say, it is wide.

The length of the PRI is normal, and remains constant.

This is a heart block and if you remember the saying:

“Same, Same, Same, Mobitz II is to blame.” Same,

Same, Same is referring to the PRI staying constant.

So putting it all together, the interpretation is:

Second degree Heart Block – Mobitz II, 2:1 AV Conduction

with a wide QRS complex.