Accelerated Idioventricular Rhythm

Report:

Accelerated idioventricular rhythm 53/min

Probable atrial fibrillation

Probable fusion beats

Comment:

The tracing is of interest, inter alia, for the Cardiologist’s report. The putative RBBB is, indeed, most atypical – the broad 0.16” monophasic R complex in V1 – and it has a changing RAD in the first two beats. The last beat – the most normal looking – ends the shortest cycle. It looks like an early and narrow capture beat – making the others ectopic ventricular. Unless one invokes supernormal conduction!

For sinus rhythm to be diagnosed, one needs constant, identical P waves at a reasonably regular rate. Lead 2 is almost useless for ventricular conduction but it does well for P waves: lead 2 is 1 + 3, arithmetically. There are no P waves there or anywhere else. The bump in front of the QRS complex in V1 as it becomes V4 is wrong shape for the lead and has no equivalents elsewhere.

Then, chronic AF. It rarely reverts to sinus rhythm. The ventricular response is obviously slow, and there is this AIVR. The likely answer is digoxin.

The following trace, 72a, is easier to interpret, by the same Cardiologist. The ventricular response is well spaced out, implying a well-blocked AV node. The QT interval is short. Digoxin. The reporter himself diagnosed one of the two VEBs (that’s why it’s marked with asterix in the report) , the one identical to the AIVR complexes above.