Runs of Aberrant SVT

Report:

Sinus rhythm

Incomplete right bundle branch block

SVEBs, some in couplets, of atrial origin

SVEBs, single, of junctional origin, dissociated

Short runs of atrial tachycardia

Aberrant conduction, RBBB type, variable

Comment:

The QR morphology is presumably predicated on a previous anterior MI ‘amputating’ primary R waves of both incomplete and complete RBBB complexes.

The patient indeed had an intermittent complete RBBB (below, in Fig 48a, entire conduction is of complete RBBB type, regardless of the rate). Note the run of AF at the beginning of the upper strip. It is not surprising for this patient to have AF: the P’ waves are premature enough to trigger it (Killip-Gault rule). Different grades of RBBB are shown here and in Fig 48b.

Whether the aberration is deemed to be phasic or non-phasic, it is perfectly acceptable to report it as rate-dependent (pedants prefer “acceleration-dependent” and “deceleration-dependent” for bradycardia-dependent variety). The longer words are winning nowadays.

48a. Plump RBBB complexes throughout. 48b. A ‘complete’ RBBB can get even more ‘complete’. An early SVEB starts an AF run in the top and the 4th strip. 49. 39 year old woman with history of tetralogy of Fallot repairs many years ago. There was no response to verapamil or sotalol.