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Second Degree Block Type Two example two



This strip is a good example of second degree block type two, with additional interesting features.
Note that the P-R intervals are constant at 0.22 seconds.  The fourth P-wave is not conducted, and a
ventricular escape beat follows.  The fifth P-wave is buried in this VEB.  The sixth P-wave is also not
conducted and a VEB follows here, also.  The seventh P-wave is buried in this VEB.  Notice that the
P-waves march out perfectly through the VEBs.  The eighth P-wave does elicit a ventricular response,
but it is aberrantly conducted.  Notice also the elevated ST segment in lead III: this patient is having
an inferior MI.  Recall that the right coronary artery, which serves the inferior wall of the ventricles,
also serves the AV node and the upper part of the bundle of His.  Occlusion of the RCA, if high enough,
will affect the functioning of the specialized conduction system.