Echo (Reentry) Beats of Junctional Origin

Report:

Top strip:

Sinus bradycardia, progressive

First degree AV block

PR 0.24”

Junctional escape beats

Retrograde first degree AV block (RP 0.28”)

Reentry (echo) beats of junctional origin

Antegrade PR interval now 0.20”

Incomplete RBBB

Bottom strip:

Junctional rhythm 42/min

1:1 retrograde conduction

Retrograde 1o VA block (RP 0.44”)

Reentry (echo) beats of junctional origin

Antegrade PR interval now 0.40”

Comment:

In the top strip the first impression is that of a birth of escape-capture bigeminy spawned by sinus bradycardia. A closer look at the P waves shows the last two to be mirror images of sinus P waves. The complexes following those are, then, reentry beats, with a tad of aberrancy on top of a pre-existing incomplete RBBB. The PT (Ta) segments are quite elevated, as are the succeeding ST segments, denoting atrial and ventricular infarction or agonal ischæmia.

A similar example, from another patient, is shown in the bottom strip. This patient, with SVC obstruction, had a catastrophic bleed from attempted cricothyroidostomy (by a surgeon) and became brain-dead.

The above are like the end-game in chess. There are only a few pieces left on the board and soon they will all be gone.