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Multifocal Couplet


This strip shows two single PVCs and a multifocal couplet, with sinus rhythm
underlying.  Notice that the two single PVCs and the first beat of the couplet
all look alike.  This indicates a single irritable ventricular focus as the
pacemaker of these three beats.   The second beat of the couplet is shaped
differently, indicating a second irritable ventricular focus (thus the term
multifocal couplet).  This can be cause for alarm: the appearance of multiple
or new irritable ventricular foci may foreshadow V-tach, and treatment with
an antidysrhythmic may be in order.  Also note that the two single PVCs are
followed by compensatory pauses, and that all three of this type of PVC have
retrograde P-waves.  Also note the doubly peaked P-waves of the sinus beats:
this indicates left atrial enlargement.