First, Second and Third Degree AV Block in the Same Patient

First, Second and Third Degree AV Block
First, Second and Third Degree AV Block


This interesting tracing show combinations of first, second and third degree AV Block in the same patient recorded over the course of a few minutes.

Lead III shows First degree AV Block with PR Interval of 0.28 sec. at a heart rate of 60/min.

In Lead V1 the heart rate increases from 60 to 80/min and Second Degree AV Block supervenes. The end of the strip of lead V1 shows prolonging PR Interval, suggesting that the preceding phenomenon (2:1 av block) was Wenckebach.

The EKG technician sought “advice”, this resulted in apprehension in the patient and caused an increase in the heart rate to 110/min. The compromised AV conduction pathways were unable to conduct the now increased number of impulses and that resulted in Third Degree AV Block seen in Lead II.

The narrow QRS morphology of the escape pacemaker suggests that it arises in the His Bundle.

A pacemaker was inserted, and the patient became asymptomatic.

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