VEB couplets: Two for the Price of One

Report:

Sinus rhythm 78/min

VEBs, frequent, some in couplets (pairs)

Poor R wave progression

Nonspecific ST/T changes

Comment:

The VEBs have typical qRR’ morphology, with left rabbit ear taller than the right; the pauses are fully compensatory. The latter are occupied by either a single VEB or a pair. Sometimes a pair can replace only one sinus beat. When this happens, there is usually (as in this case) some prolongation of the next PR interval – concealed retrograde conduction.

A similar trace obtained a little later also shows a run of atrial bigeminy (Fig 224a); one has to look twice to see that the early P’ waves are different from sinus P waves. I must admit my first thoughts were about zebras: sinus extrasystoles or SA 3:2 Wenckebach. There is a triplet VT at the end.

The next example (Fig 224b) shows three for the price of one, in a 69 year old man with large old anterior MI invisible on his ECG, perhaps masked by an incomplete LBBB. His next trace (Fig 224c) is appended because it shows directly the sinus cycle length, and two for the price of one again.