Digoxin-Induced Wenckebach

Report:

Sinus arrhythmia

Second degree AV block, Möbitz 1

Comment:

The respiratory effect on the QRS size is seen throughout. It may be tempting to assume the first and largest QRS in each sequence is a junctional escape beat, with non-phasic aberrancy; but comparison of escape interval in the top strip with the others below shows the interval to be dependent on the sinus rate alone. There is some (normal) respiratory sinus arrhythmia, but the initial PR interval in each Wenckebach sequence is the same, just under 0.20”. Dissociated junctional escapes would show some variation of that interval.

The concordant T wave inversion with a superiorly oriented QRS vector is very likely abnormal in this lead. It is wise, however, to restrict the commentary to rhythm and conduction only in the rhythm strips.

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