An Unusual Agonal Alternans

Report:

Sinus bradycardia 46/min

First degree AV block

PR 0.64”

Second degree AV block, 3:2 then 2:1

Left atrial abnormality

Left bundle branch block

QRS 0.42”

T wave alternans

Comment:

The T wave is unaccountably flattened in alternate cycles, permitting sharp definition of the following P waves. Alternate P waves are ‘buried’ in the descent of the larger T waves, but can be just made out when looked for.

The QRS complexes, grotesquely prolonged as they are, do not share in the alternans: if one covers all the trace above the isoelectric line, they cannot be distinguished from one another morphologically.

Below are strips of the agonal rhythm starting (Fig 200a) and stopping (Fig 200b). Remarkably the alternans persisted almost to the very end and the last beat was a conducted sinus one, albeit with 1o and 2o AV and atrial blocks and 0.4” LBBB.

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