Alternating Retrograde Conduction in Accelerated Junctional Rhythm

Report:

Accelerated junctional rhythm 92/min

2:1 retrograde block

Right axis deviation

Lateral infarction, acute or recent

Borderline small voltage in frontal leads

Electrical alternans V1

Comment:

One would be tempted to say that this trace is an example of lead 2 being actually better than V1 for the rhythm strip, clearly showing retrograde P waves almost invisible in V1. The truth is, one should always chose the rhythm strip on the basis of the diagnostic purpose one has in mind. Here lead 3 would be better still.

But lead V1 may still be more useful overall. It is the only lead to show electrical alternans signifying severe LV failure the patient had (and, in fact, died from a few weeks later). Sometimes V1 is the only lead showing alternans36.

Below is another trace, taken a fortnight later, with the same rhythm now conducted completely to the atria (Fig 53a). The infarct pattern has evolved a little (with T inversion in 1 and aVL) but the sinister ST elevation and its reciprocal counterpart in the inferior leads persist. Lead V1 is now definitely useless, an exception to the general rule.

It should be noted that “lateral” infarction is an electrocardiographic convention, far from denoting a localised area of the free wall37. This patient had most of her heart akinetic or severely hypokinetic, with only a little septal movement left.

Her initial ECG, with Wellens’ warning in the precordial leads, and acute anterolateral infarction that followed, are shown below (Fig 53b, Fig 53c).