Continuing ventricular ectopy, let us start with ventricular couplets.

Two consecutive ventricular ectopics (red highlight).The cycle length between the ectopics may not always be short (red highlight):

Couplets are not always identical but may appear to come from the same focus with different conduction or aberration (red highlight).

The differences with the first example may be related to the underlying bundle branch block.Ventricular interpolation can occur with couplets. For timing purposes, the sinus cycle should be long with the ectopics having a short coupling period (red highlight).

The first ectopic is within the PR interval and the embedded concealed P wave (stippled red arrow) conducts to the ventricle with a very long PR interval.And then there are multifocal ventricular couplets:

Note the position of the embedded concealed sinus P wave (red stippled arrow).Not all multifocal couplets are couplets! Again it is in the timing.

The embedded sinus P wave in the T wave can be seen and conducts to the ventricle with aberration. Thus this is a late interpolated ventricular ectopic rather than a couplet.To summarize:

On the left is an obvious multifocal ventricular couplet with two embedded concealed sinus P waves (red highlight).On the right is an apparent multifocal ventricular couplet, but only one embedded concealed sinus P wave which may have conducted to the ventricle with aberration (red highlight).On occasion ventricular couplets can occur in groups:

This is reversed trigeminy. My technicians have given it a name; unipolar bigemilets, because it is an amalgam of bigeminy and couplets.Obviously, there must be trigemilets.

A triplet is three consecutive ventricular ectopics (red highlight).

Some authorities refer to this as ventricular tachycardia if >100 bpm or a ventricular run if <100 bpm.A ventricular triplet may be multifocal:

A salvo is a run of 3 to 5 ventricular ectopics:

Multifocal salvos look and may be sinister.When the rhythm is slow it is called an idioventricular rhythm (red highlight):

Fusion beats are very common (yellow highlight).Cycle lengths may differ during a salvo:

I will discuss this ECG in more detail in a future presentation.Remember, it’s all in the timingHarry Mond