Pacemaker Blues

Report:

[Code Blue]

Pacemaker rhythm 72/min 1

QRS 0.36” 2

Pacemaker rhythm 72/min 1

QRS 0.20” 2

AV dissociation 2

Accelerated idioventricular rhythm 78-84/min 2

Comment:

The QRS complex width - in paced beats, bundle branch blocks, or VEBs - generally correlates with myocardial disease. This patient’s QRS width is greatly exaggerated by hyperkalæmia, loss of cardiac output and attendant acidosis and hypoxæmia, as in the agonal Case 35. It almost halved with successful resuscitation.

Note also the increased P wave amplitude with correction of hyperkalæmia.

The pacemaker’s sensing function was obviously retained during the AIVR. A magnet would have converted it to paced rhythm, but it would make little sense in this setting – the AIVR’s faster rate was probably more favourable. In fact, the magnet would best be left over the generator, to produce sustained pacing at 100/min if the unit was so programmed.

If you have any suggestions for or feedback on this report, please let us know.