Rule of Bigeminy: VEBs & SVEBs

Report:

Sinus rhythm

First degree AV block (PR 0.26”)

Right bundle branch block (QRS 0.14”)

VEBs

SVEBs, junctional

Comment:

All four SVEBs follow, after one cycle, the VEBs and the last VEB in the bottom strip follows a SVEB, perhaps reflecting the ‘rule of bigeminy’. This is different from VEBs or SVEBs following one another immediately, through reentry or sudden change in cycle length.

The SVEBs are dissociated from the preceding sinus P waves, as are the VEBs. The former are traditionally designated as junctional, but may well be bundle of His extrasystoles.

Some of the extrasystoles also have antecedent but unattached (Marriott’s phrase) P waves in front of them. That, at least, precludes atrial origin of the extrasystoles.

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