Complete Heart Block

Report:

Sinus rhythm 72/min

Third degree AV block

Junctional escape rhythm 31/min

Left atrial abnormality (LAA)

Rightward axis, unusual for age

Right bundle branch block

Prolonged QT interval (0.70”)

QTc 0.50”

Comment:

This is a typical complete AV block: the sinus rate is more twice the rate of the junctional escape. There is ample opportunity for conduction, but it does not happen. Because of the block.

The axis is rightward, between +85o and +90o, but not really deviated to the right. Lead 1 is essentially equiphasic. In the presence of RBBB, only the initial 0.06” - the unblocked part of the QRS – counts in frontal axis estimation. There is certainly no posterior hemiblock present and if there were, it would not matter anyway: there is a complete AV block already present.

The QT interval is long, even for this slow rate. The reason in this case remains unknown.

The patient remained unpaced but unchanged for the next 24 hours (Fig 61a). A permanent pacemaker was implanted later.

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