Failed Pacemaker?

Report:

Sinus tachycardia 104 - 124/min

First degree AV block[!xe "PR interval:long" \t "See AV block, first degree"!]

Second degree AV block, probably Möbitz 2

Third degree AV block

Ventricular standstill

Junctional escape rhythm, ventricular escape beat (last in the bottom strip)

Ventricular conduction delay (QRS 0.14”)

Probable LBBB

Comment:

There is no observable prolongation of the PR interval prior to the completely blocked P wave. In long Wenckebach sequences, however, the prolongation may be minimal toward the end of a period. Presence of LBBB supports - although by no means strongly - Möbitz 2 mechanism. When exactly one decides that second degree AV block has become third degree is a moot point; one could argue that the third degree block sprang directly from the first degree.

The escape rhythm is called junctional because it looks similar, but not identical, to the sinus rhythm conducted with LBBB. A ventricular escape rhythm would have a slurred S descent.

The patient survived the night on her own resources in the CCU, without any action being taken prior to Charge Sister coming to discover the disconnected wire in the morning! The Cardiology Registrar arrived next and wrote: “Note non-capturing of pacing wire last night”. Indeed.

Things happen in a big hospital. Sometimes they don’t. Sometimes this means the same thing.